## 1. What is Moral Naturalism?



Moral naturalism is the view that moral facts are stance-independent,
natural facts. It can also be characterized as the view that moral
properties are stance-independent, natural properties.



**Fact Naturalism:** Moral facts are natural facts.



**Property Naturalism:** Moral properties are natural
properties.



These two views are subtly different because there are different kinds
of moral facts. Particular facts are instantiations of some property;
particular moral facts are instantiations of some moral property;
particular natural facts are instantiations of some natural property.
So Fact Naturalism entails Property Naturalism: if all moral facts are
natural, then all particular moral facts are instantiations of natural
moral properties. But not all moral facts are particular facts.
General moral facts, like the fact that genocide is wrong, consist in
either patterns of instantiations of moral properties or underlying
lawlike moral principles which explain those patterns of
instantiations. Underlying moral principles do not consist in
instantiations of moral properties; it is possible that genocide is
wrong but never committed, in which case there would be no
instantiation of a moral property of wrongness to correspond to the
principle that genocide is wrong. So while Property Naturalism entails
that all *particular* moral facts are natural facts, Property
Naturalism does not entail Fact Naturalism because it's possible
that moral *principles* are non-natural. For ease of
exposition, I'll mostly ignore this complication in what
follows, and treat Fact Naturalism and Property Naturalism as
interchangeable while focusing on Fact Naturalism as the stronger
thesis. But moral principles will cause trouble at a few points.



A fact is stance-independent just in case it doesn't depend on
the beliefs or attitudes of any agent. Moral realism is the view that
moral principles are stance-independent; this is a more precise way of
capturing the common idea that, for a realist, morality is a matter of
fact rather than a matter of opinion. But what does it mean for a fact
(or property) to be natural? The usual answer is that natural
facts/properties are the kinds of facts/properties that scientific
methods tell us about (see, e.g., Shafer-Landau 2003, Chapter 3; Smith
1994, 17; Copp 2007, 27-28). To say that moral facts are natural
facts, then, is to say that moral facts are part of the naturalistic
picture of the world that is revealed by empirical science.



Moral naturalism is opposed to moral supernaturalism, which holds that
moral facts are a kind of supernatural (typically, divine) facts. It
is also opposed to moral non-naturalism, which holds that moral facts
are neither natural nor supernatural, but are rather their own, third
kind of thing. And as a version of moral realism, moral naturalism is
opposed to all varieties of anti-realist views in metaethics,
including constructivism, relativism, expressivism, and error theory.
While anti-realists are usually naturalists in the sense that they
want to account for morality in naturalistic terms, anti-realists hold
that stance-independent moral facts can't be reconciled with a
naturalistic worldview. Moral naturalists hold that they can be.



For the naturalist, moral facts are the kinds of facts that can be
investigated by (broadly) scientific methods. But what kinds of facts
can be investigated by scientific methods? There is much less
agreement on how to answer this further question. One common view is
that facts can be empirically investigated just in case they are
capable of entering into causal explanations of our experiences, and
thereby be investigated through those experiences (e.g., Bedke 2009;
Enoch 2010; Lutz 2020). And while most (perhaps all) moral naturalists
would say that moral facts can feature in causal explanations, this
may not be a good characterization of natural facts, since
supernatural facts could, perhaps, also feature in causal explanations
(Sturgeon 2009; McPherson 2015). We could try to solve this problem
with brute force, by defining a natural fact as any fact that features
in causal explanations that is not a supernatural fact. But this is ad
hoc; and now we need to characterize supernatural facts. We might also
worry about what it means for a fact to feature in a causal
explanation, which is itself a vexed and controversial issue. Perhaps
it is best, then, to just leave it at "natural facts are facts
that are known scientifically."



But even this minimal characterization faces difficulties. For one
thing, it is extremely controversial which methods count as
"scientific." The "demarcation problem" of
distinguishing science from non-science (or
"pseudoscience") is a perennial puzzle in the philosophy
of science, with many philosophers doubting that there is any general
way of characterizing scientific methodology (Feyerabend 1975). A
second problem is that this is a methodological or epistemological
characterization of the natural; rather say what kinds of facts moral
facts *are*, moral naturalism would be a view about how moral
facts are *known*. This is, in fact, how some characterize
moral naturalism and non-naturalism. In *Moral Realism: A
Defense*, Russ Shafer-Landau affirms a number of metaphysical
theses that are commonly associated with moral naturalism, most
notably saying that moral facts are entirely constituted by more
fundamental natural facts (Shafer-Landau 2003, 74-8). Yet he
still calls himself a non-naturalist, because he thinks that we have
moral knowledge by intuition and reflective equilibrium rather than by
scientific methods (Shafer-Landau 2003, 56-58ff). Some critics
have argued that Shafer-Landau is actually a naturalist in virtue of
his metaphysical commitments (Bedke 2012, fn 1). But if a
methodological characterization of the natural is best, then
Shafer-Landau has labeled his view correctly.



So far, we have characterized moral naturalism in terms of four
claims:



**Moral Realism:** There are stance-independent moral
facts.



**Fact Naturalism:** Moral facts are natural facts.



**Property Naturalism:** Moral properties are natural
properties.



**Methodological Naturalism**: We know about moral claims
in the same way that we know about claims in the natural sciences.



But moral naturalism is sometimes associated with a fifth,
*linguistic* claim, about the nature of moral language. That
claim is:



**Analytic Naturalism**: Our moral claims are
*synonymous* with certain (highly complex) claims in the
natural sciences.



It might be tempting to say that moral naturalism is the conjunction
of these five claims, but there is a strong tension between
Methodological Naturalism and Analytic Naturalism. If Analytic
Naturalism is true, then it should be possible to analyze moral claims
and show what claims in the natural sciences they are synonymous with.
But if this is possible, then substantive moral principles are
knowable not via scientific methods but via a priori conceptual
analysis. Analytic Naturalism therefore seems to entail that
Methodological Naturalism is false, and vice versa. Naturalists who
accept Analytic Naturalism are called, appropriately enough, analytic
naturalists. Naturalists who reject Analytic Naturalism are synthetic
naturalists.



This distinction between analytic naturalism and synthetic naturalism
creates further trouble for our ability to characterize moral
naturalism. If moral naturalism is the view that moral facts are known
by empirical methods, then analytic naturalism is not a version of
naturalism at all (Flanagan, Sarkissian, and Wong 2016). Yet many
would resist the suggestion that analytic naturalists aren't
naturalists, since the term "moral naturalism" was coined
to refer to analytic naturalism; synthetic naturalism is a relatively
recent entrant to the metaethical scene.



Perhaps we can resolve this conflict by recalling the difference
between particular moral facts and moral principles. Analytic
naturalists agree with synthetic naturalists that we should be able to
investigate particular moral facts empirically. An analytic naturalist
who held that 'good' was synonymous with
'pleasurable' (e.g.) would agree that whether or not a
particular action instantiates goodness/pleasure is the sort of thing
we can investigate empirically. And synthetic naturalists agree with
analytic naturalists that certain claims about the relations between
our moral concepts, like "if it is morally required to help
others, then it is not morally forbidden to help others," can be
analytic and knowable a priori (although see Howard and Laskowski
2021). What is primarily at issue in the debate between analytic and
synthetic naturalists is the status of claims about moral principles.
Analytic naturalists hold that these claims are analytic; synthetic
naturalists hold that they are not. So if we define moral naturalism
in terms of Property Naturalism and remain neutral on Fact Naturalism,
this sidesteps the question of the nature of moral principles; perhaps
this can mend the rift between analytic and synthetic naturalists. But
questions about the nature of moral principles seem awfully to the
metaphysics of morality, so perhaps we don't want to sidestep
them. And Property Naturalism doesn't help answer the earlier
worries we had about how to characterize moral naturalism: What
properties are the kinds of properties that can be investigated by
scientific methods, and what methods for investigating those
properties are the scientific ones?



One more characterization of moral naturalism is worth mentioning. It
is increasingly popular to think that appeals to the notion of
"grounding" can help clear up what is at stake in a
variety of metaphysical debates, and so some believe that we can
explain naturalism in terms of grounding:



**Grounded Naturalism**: All moral facts are fully
grounded in non-normative facts (Rosen 2017a).



But it's not clear if this draws the line between naturalism and
non-naturalism in the right place. One problem is that it's
controversial what the relationship between "natural
facts" and "non-normative facts" is (see Section 4.2
below). Another problem is that "grounding" is itself a
highly contested notion. "Grounding" refers to some sort
of asymmetric determination relation which is supposed to be
"almost maximally intimate" (Rosen 2017a, 157). It is
"almost" maximally intimate because the maximally intimate
relation is identity, but grounding is not identity; unlike identity,
grounding is asymmetric. Non-naturalists would reject the idea that
moral facts are identical to non-normative facts. But grounding is
*not* identity; so why *can't* non-naturalists say
that the relationship between the moral and the non-normative is
*almost* maximally intimate? Some self-described
non-naturalists say that moral facts are entirely grounded in
non-normative facts (Moore 1942; Bader 2017; compare Leary ms -
see Other Internet Resources). What's wrong with that? What does
it mean for a relation to be "almost" maximally intimate
in the first place?



Sometimes philosophers clarify the notion of grounding by saying that
the grounded facts are "nothing over and above" the
grounding facts (Rosen 2017a, 157). But putting things this way
threatens to show too much. If moral facts are "nothing over and
above" the non-normative facts, then moral facts would
apparently have to be non-normative facts; normativity seems to count
as something "over and above" non-normativity. But many
moral naturalists say that moral facts are normative (again, see
Section 4.2). Perhaps it is coherent to say that the normative is
"nothing over and above" the non-normative; many good
philosophers speak this way and we shouldn't write them off as
confused. But "nothing over and above" is no more clear
than "almost maximally intimate." So we lack a clear
picture of what grounding consists in, and it's consequently
unclear why non-naturalists can't say that moral facts are fully
grounded in non-normative facts but naturalists can.



We could say that naturalism is the view that moral facts are grounded
in *natural* facts rather than in *non-normative* facts
(Chilovi and Wodak 2022). It's (arguably) clearer why this is
the sort of thing that naturalists would want to say and
non-naturalists wouldn't, but this formulation doesn't
help us understand what natural facts are in the first place.



All moral naturalists will agree with the claim that morality is
natural. But there's depressingly little agreement on how to
understand the "naturalness" of morality. It's all a
bit of a muddle.


## 2. Descriptivism and Reductivism



This section will look at two views closely associated with
naturalism, descriptivism and reductivism. Many philosophers who call
themselves descriptivists or reductivists also call themselves
naturalists (or at least end up taking the same side as self-described
naturalists in many metaethical debates). Perhaps we can usefully
characterize naturalism in terms of either of these views.



**Naturalism as Descriptivism**: Moral facts are natural
facts if and only if (and because) descriptivism is true.



**Naturalism as Reductivism**: Moral facts are natural
facts if and only if (and because) reductivism is true.



More modestly, even if Naturalism as Descriptivism and Naturalism as
Reductivism don't pan out, we might prefer to just focus on
descriptivism or reductivism as interesting views that capture many of
the same ideas that incline philosophers toward naturalism.


### 2.1 Descriptivism



Many philosophers have found it intuitive that there is a distinction
between terms like 'good,' 'bad,'
'right,' 'wrong,' or 'reason,' on
the one hand and terms like 'pink,' 'shiny,'
'bigger than a bread box,' or 'pleasurable' on
the other. The terms on the first list are called *normative
terms* while the terms in the second list are *descriptive
terms*. It is (mostly) uncontroversial that moral terms are
normative terms; so, if we refer to moral properties using moral terms
(contra some expressivists and some error theorists), some normative
terms refer to moral properties. *Moral descriptivism* is the
view that some descriptive terms refer to moral properties as well
(Heathwood 2009).



Moral descriptivism is closely related to moral naturalism. Let us
assume, as seems plausible, that the things that scientists
investigate are things that can be referred to with descriptive
language. Good science doesn't moralize, it just says how things
are. If this assumption is correct, then analytic naturalism entails
descriptivism. If moral claims are synonymous with scientific claims
and scientific claims are made using descriptive language, then moral
claims are synonymous with descriptive claims. Moral terms refer to
moral properties; any synonymous terms would refer to those same
properties; therefore, there are descriptive terms that refer to moral
properties.



Synthetic naturalists can be descriptivists, too. According to
synthetic descriptivism, there are descriptive terms that refer to
moral properties, but this is not so in virtue of any analytic
relation between normative and descriptive terminology. Rather, the
synthetic descriptivist argues for the existence of synthetic property
identity claims. The paradigm synthetic property identity is
"water is H2O." 'Water' and
'H2O' are just two different labels for the
same thing. But 'H2O' is not the definition of
'water;' that water is H2O was not, and could
not have been, discovered by pure conceptual analysis. It is a
synthetic truth known a posteriori. Synthetic descriptivists hold that
descriptive terms which refer to moral properties reveal synthetic
property identities, just as in the case of water and
H2O.



However, even though analytic naturalism entails descriptivism and
synthetic naturalism is consistent with descriptivism, Naturalism as
Descriptivism is false. The first problem is that many supernatural
terms are descriptive. So it's possible that moral properties
are supernatural (e.g. divine) properties and descriptive terms refer
to those moral, supernatural properties. In this case, descriptivism
would be true and naturalism false (Sturgeon 2009).



Another serious problem for Naturalism as Descriptivism is that, while
analytic naturalism entails descriptivism, synthetic naturalism
doesn't. There's no reason why facts that can be
empirically investigated and fit comfortably with a scientific
worldview must be referred to with descriptive terminology. A
naturalist can say that goodness is a natural property that is known
via empirical methods and features in causal explanations, and the
only term that refers to goodness is 'goodness.' Jonathan
Dancy calls this non-descriptivist naturalism "one-term
naturalism," since one-term naturalists say that there is only
one term - a moral term - that refers to moral properties
(Dancy 2006).



Incidentally, because naturalism doesn't entail descriptivism,
one common challenge to naturalism fails: "You say that goodness
(e.g.) is a natural property, but which natural property is it?"
For a naturalist may reply: "Goodness is a natural property. The
only natural property that goodness is identical to is itself:
goodness." This is a coherent and complete answer to the
challenge (Sturgeon 2003). The challenger seems to be demanding that
the naturalist pick out the property of goodness using descriptive
terminology. This is an apt challenge to descriptivism but not to
naturalism. One-term naturalists are not descriptivists (Vayrynen
2021).



But while Naturalism as Descriptivism seems like a non-starter,
perhaps descriptivism is an interesting view in its own right. We
might even prefer to talk about descriptivism rather than naturalism
in light of our difficulties with characterizing naturalism.
Unfortunately, there are also problems with characterizing
descriptivism.



One problem is that it's actually rather easy to refer to moral
properties with descriptive terminology. Goodness was the primary
subject of G.E. Moore's *Principia Ethica*. So the phrase
'the subject of *Principia Ethica*' refers to
goodness, and that phrase uses only descriptive terminology. But this
isn't a proof of descriptivism; descriptivists want some
stronger relation between descriptive language and moral properties.
But it's hard to say what that stronger relation might be.



A second problem is the existence of "thick" normative
terminology, which apparently expresses both descriptive and normative
concepts, or perhaps concepts that are both descriptive and normative.
Common examples include 'brave' (and other virtue terms),
'cruel,' or even, perhaps, 'pleasurable'
(Roberts 2017, 212). Frank Jackson (1998) proposes that thick
terminology, and any other terminology about which there could be
doubt as to classification, should be considered normative. Perhaps
that solves the problem.



A third problem concerns our method for characterizing normative and
descriptive terminology. We started out with two contrasting lists of
terminology, saying that one of the lists was a list of normative
terminology and the other list, the "everything else"
list, was a list of descriptive terminology. But our list of normative
terminology was incomplete. Normative terminology includes everything
on that list and all other terminology that is similar. But what does
all this normative terminology have in common in the first place? What
makes a term normative? One way of characterizing normative
terminology is broadly functional: normative terminology expresses
thoughts which regulate our actions in certain ways. But embracing a
functional account of normative terminology cedes much ground to
expressivists, who hold that the meaning of normative terminology just
is to express action-regulating states. And characterizing normative
terminology in functional terms also deprives moral realists (and thus
moral naturalists) of one of their main arguments for realism, since
the existence of moral facts may no longer be read directly off of the
semantics of moral terms (Eklund 2017). For that reason, some realists
prefer to characterize normative terminology in referential terms:
normative terminology is terminology that refers to normative
properties (Hernandez and Laskowski 2021). But if we give a
referential characterization of normative terminology, it's no
longer obvious how to draw our distinction between normative and
descriptive terminology. If a bit of terminology that we would
intuitively put on the list of descriptive terminology ends up
referring to a moral property (which happens, according to
descriptivists!), then that terminology is ipso facto normative. So on
a referential account, which terms count as normative and which count
as descriptive is not discoverable by simple reflection on the
meanings of the terms, but must instead involve substantial ethical
and metaethical theorizing. A referential account of normative
terminology would also threaten to render descriptivism incoherent,
since any terminology which referred to a moral property would be
normative rather than descriptive.


### 2.2 Reductivism



Another view that is often closely associated with naturalism is
"reductivism." The reductivist says that moral properties
reduce to some other kind of property. Again, we might be interested
either in Naturalism as Reductivism as an ambitious attempt to
characterize moral naturalism, or just in reductivism as an
interesting view in its own right. Unfortunately, it is unclear what
it means for one property to reduce to another. 'Reduce'
is a philosopher's term of art, but it is used in very different
ways by different philosophers. We're in for another muddle; but
let's try to clear things up a bit.



We should note at the outset that there is a paradigm example of a
reductive view, which is used almost every time a metaethicist
discussing reductivism needs a toy example to play with. That paradigm
is the hedonic reduction: that goodness *is* pleasure and
therefore *reduces to* pleasure. This introduces a key
desideratum of any account of reduction: that it should count the
hedonic reduction as a reductive view.



That said, let's begin with one of the clearest things written
about reduction. Here's Nicholas Sturgeon:



> 
> 
> Naturalism is in one clear sense a 'reductionist' doctrine
> of course, for it holds that moral facts are nothing but natural
> facts. What I deny, however, is that from this metaphysical doctrine
> about what sort of facts moral facts are, anything follows about the
> possibility of reduction in another sense (to which I shall henceforth
> confine the term) more familiar from the philosophical literature:
> that is, about whether moral expressions can be given reductive
> definitions in some distinctive nonmoral vocabulary, in which any
> plausible moral explanations could then be recast (Sturgeon 1988,
> 239-240).
> 
> 
> 



Sturgeon here distinguishes two distinct senses of the term
'reduction.' One is linguistic. A term can be reduced to
another term just in case the first term can be defined in terms of
the second. In this sense, reductivism is just another name for
analytic naturalism. In later work, Sturgeon mentions the possibility
of "synthetic reductions" (Sturgeon 2009), so I think
it's more accurate to say that Sturgeon's reductivism is
another name for descriptivism. Note that the hedonic reduction is a
descriptivist view since it states that the descriptive term
'pleasure' refers to the moral property of goodness. So
the linguistic sense of 'reduction' as another name for
descriptivism satisfies our key desideratum.



Let's pause for a second to clear up another perennial source of
confusion about how metaethical terminology is used. Sturgeon and the
other Cornell realists (see Section 6) call themselves
"non-reductive" naturalists; but when they say this, they
aren't describing any distinctive metaphysical commitments of
their view. They are simply rejecting descriptivism. Sturgeon, at
least, is perfectly clear about this in the above quote. There are
metaphysical doctrines associated with Cornell realism, of course,
(again, see Section 6). But as the Cornell realists used that term,
"non-reductive" naturalism is just naturalism without
descriptivism, i.e. one-term naturalism.



If we understand 'reduction' in its linguistic sense,
reductivism is synonymous with descriptivism, and so we have a
redundant bit of terminology. That's a good reason to understand
reductivism as a distinct, metaphysical doctrine. So: what is a
metaphysical reduction? We might look to general metaphysics for help
here. Unfortunately, metaphysicians use the term 'reduce'
in lots of different ways; there is no one standard account for us to
borrow (Stoljar 2010, 161-162; McPherson 2015). But perhaps we
can get a sense of the general idea. In recent years, there has been a
proliferation of terms within metaphysics that all seem to be aimed at
capturing the same idea: we can say what something is composed of, or
what it is grounded in, or what it reduces to, or what the real
definition of a thing is, and all of those locutions seem to be aimed
at capturing the same thought (Rosen 2015). All of these locutions are
ways of articulating *what it is to be* some thing by saying
*what it is made of* (compare Schroeder 2005; Schroeder 2016).
One key idea here is that if A reduces to B, then A is less
fundamental than B (Laskowski 2020). Let's call this the
Fundamentality Platitude.



If we understand reductivism as a metaphysical thesis about
fundamentality, per the Fundamentality Platitude, we can make a
plausible case for Naturalism as Reductivism. Any naturalist will say
that the fundamental entities are the sorts of objects and properties
that are the subject matter of fundamental physics: bosons and leptons
(etc.) with their spin and mass (etc.). Goodness is not one of those
fundamental physical properties; goodness is a higher-level property
which is ultimately composed of fundamental physical properties, the
same as any other natural property. Naturalists are, in this way,
metaphysical reductivists. And because non-naturalists deny that moral
properties are natural, their account of the nature of moral
properties is not constrained by the physicist's account of
fundamental properties. A non-naturalist might well say that some
moral properties are metaphysically fundamental. So naturalists say,
whereas non-naturalists may deny, that all moral properties reduce to
non-moral, physical properties. That's Naturalism as
Reductivism..



However, there are problems with this argument. First, supernatural
properties cause trouble again. If moral properties are reducible to
supernatural properties, then reductivism is true and naturalism false
(Sturgeon 2009). As before, we could try to finesse this by talking
about "reductive naturalism," the view that moral
properties reduce to natural properties, in particular. Many
philosophers do speak this way. But we can't characterize
naturalism as the view that moral properties reduce to natural
properties unless we already know what natural properties are. So talk
of reductive naturalism means giving up on Naturalism as
Reductivism.



So let's set aside the more ambitious Naturalism as Reductivism
and just focus on reductivism as a potentially interesting and
important view in its own right. Unfortunately, there are problems
with giving a useful metaphysical characterization of reductivism.
Consider the hedonic reduction: that goodness reduces to pleasure in
virtue of being identical to pleasure. Some philosophers defend the
idea that pleasure is metaphysically fundamental. If we combine
pleasure fundamentalism with the hedonic reduction, we end up with the
view that goodness is both reducible and fundamental (McPherson and
Plunkett forthcoming). So depending on what we say about the
metaphysics of pleasure, the hedonic reduction may not be consistent
with the Fundamentality Platitude..



There's a larger problem lurking here. We've characterized
two different ideas as key to contemporary discussions of reduction in
metaethics: the Fundamentality Platitude and the hedonic reduction.
The hedonic reduction counts as a reductive view because of another
platitude about reduction: that identity entails reduction. Call that
the Identity Platitude. Here's Graham Oddie:



> 
> 
> Exactly what is reduction? Take two kinds of entities, Type-A entities
> and Type-B entities. Although reduction is a contested notion, here is
> an undeniably *sufficient* condition for the reducibility of
> type-A entities to type-B entities: every type-A entity is
> *identical* to some type-B entity. (Oddie 2005, 15, italics in
> original)
> 
> 
> 



The larger problem is that the Identity Platitude and the
Fundamentality Platitude are inconsistent. Identity is a symmetric
relation, but being-less-fundamental-than is an asymmetric relation,
so nothing can satisfy both of those platitudes. If reduction is
asymmetric, then reduction is not entailed by identity, and so the
Identity Platitude is false. If reduction is not asymmetric, then the
fact that A reduces to B doesn't entail that A is less
fundamental than B, and so the Fundamentality Platitude is false.



Here's another way to demonstrate the point. Consider a close
cousin of the hedonic reduction, the view that rightness is identical
to conducing-to-pleasure. Conducing-to-pleasure is a complex property,
composed of pleasure, conducing, and perhaps some abstract structural
elements. On this view, rightness is identical to
conducing-to-pleasure, and rightness is composed of and less
fundamental than conducing and pleasure. So rightness stands in a
different relation to the complex conducing-to-pleasure than it does
to the simpler elements. Which of those two relations is the reduction
relation? 'Reduction' is a term of art; it means whatever
philosophers mean by it. And, unfortunately, philosophers use the term
'reduction' to refer to both of those relations. So not
only is 'reduction' ambiguous between a linguistic and a
metaphysical concept, there's a further ambiguity in the
metaphysical use of the term.



Let's sum up the discussion thus far. We were looking for an apt
characterization of moral naturalism, and had a hard time finding one.
We then looked at two ways of characterizing naturalism in terms of
other theses associated with naturalism: descriptivism and
reductivism. We found that there are substantial problems with
characterizing naturalism in terms of either descriptivism or
reductivism, and that there are further problems with trying to
characterize descriptivism and reductivism themselves. So while
philosophers frequently use the terms 'naturalism,'
'descriptivism,' and 'reductivism' when
describing various metaethical views, there's no way to define
those terms that isn't highly controversial. In light of this
depressing and distressing realization, there's only one thing
to be done: ignore all of this and press on as though we know what
we're talking about when we use these terms. That is,
unfortunately, what philosophers in this area tend to do. So even
though there's little agreement about what naturalism is,
let's see what philosophers have said about naturalism.


## 3. Why be a Moral Naturalist?



Moral naturalism is a very popular view (although it might be more
accurate to say that "moral naturalism" is a popular
label...). That's because moral naturalism is the
conjunction of two views that are themselves very popular. The first
is naturalism: that everything which exists is natural. The second is
moral realism: that stance-independent moral facts exist. Combine
these two, and we get the conclusion that moral facts (exist and) are
stance-independent natural facts. Thus:



**The Basic Argument for Moral Naturalism**

1.
Naturalism
2.
Moral Realism
3.
Therefore, Moral Naturalism



We'll look at more technical arguments for moral naturalism
shortly, but the Basic Argument is the reason why so many
metaethicists have a default sympathy for moral naturalism. It's
a popular conjunction of two popular views. Naturalism has proven to
be the most successful project, ever, for advancing human knowledge
and understanding. The success of naturalism doesn't entail that
that nothing exists which can't be accounted for
naturalistically, nor does it entail that there are no other projects
that could successfully advance human knowledge and understanding. But
many philosophers suspect that empirical methods have been so
dramatically successful in shedding light on so many different areas
of inquiry because some version of naturalism is correct.
(Non-naturalists disagree, of course!)



Similarly, moral realism is a popular view. There are many different
moral claims - that rape and murder are wrong, for instance, or
that helping others in need is good - that have the status of
common sense. We treat these common sense moral claims, at least
implicitly, as accurately describing reality and not being mere
matters of opinion. Moral realism is popular precisely because it
promises to do justice to this common attitude towards our moral
commitments. (Anti-realists disagree, of course!)


### 3.1 Arguments from Supervenience



Let's turn to the more technical arguments for naturalism. There
are two distinct arguments for moral naturalism that begin from the
premise that the moral supervenes on the natural.



**Supervenience**: There are no two metaphysically
possible worlds where the natural facts are the same but the moral
facts are different.



As we saw in Section 1, any two worlds that are identical with respect
to the moral facts are identical with respect to both moral principles
and instantiations of moral properties. So Supervenience entails the
related claim that no two metaphysically possible worlds have the same
distribution of natural properties and a different distribution of
moral properties.



The first argument, the Direct Argument, comes from Frank Jackson
(Jackson 1998, 118ff. See also Streumer 2008; Brown 2011; Clarke
2019). Supervenience is the first premise of the Direct Argument. The
second is



**Intensionalism**: If it is metaphysically necessary
that something has property *F* if and only if it has property
*G*, then *F* and *G* are the same property.



Intensionalism and Supervenience together entail naturalism. Consider
the moral property of wrongness. Every wrong action has some natural
features; call the features of a given wrong action \(N\_1\).
Supervenience entails that any action with \(N\_1\) is necessarily
wrong. Of course, there is more than one action that is wrong, but the
argument generalizes. Call the natural features of a second wrong
action \(N\_2\). Supervenience entails that any action with \(N\_2\) is
necessarily wrong. And so on, for all natural features of wrong
actions \(N\_1 \ldots N\_n\). Now consider the disjunctive property
(\(N\_1\) or \(N\_2\) or ... \(N\_n\)). Let's call that
disjunctive property \(N\). Because \(N\) is a disjunction of natural
properties, it is itself a natural property. Any action that has \(N\)
is necessarily wrong. And because \(N\) is the disjunction of the
natural features of all morally wrong actions, any action that is
wrong necessarily has \(N\). So, necessarily, an action is wrong if
and only if it has \(N\). Therefore, by Intensionalism, wrongness is
identical to \(N\). And because \(N\) is a natural property, wrongness
is a natural property. QED.



The most obvious way to object to the Direct Argument is to reject
Intensionalism (see, e.g., Bader 2017). A common example in the debate
over Intensionalism is the pair of properties *being
triangular* and *being trilateral*. Necessarily, anything
that has one property has the other: if a figure has three angles, it
also has three sides (Bealer 1982). Enemies of Intensionalism say the
two properties aren't the same: one property is a property
figures have in virtue of the number of angles they possess, while the
other is a property figures have in virtue of the number of sides they
possess. Defenders of Intensionalism say that these are the same
property: there's no difference between being three-sided and
being three-angled, and that's precisely because those
properties are necessarily co-instantiated. This is an ongoing debate
in metaphysics.



The Direct Argument also relies on the assumption that disjunctions of
natural properties are natural properties, but that's a dubious
assumption. Many would claim that disjunctions of properties
aren't properties at all, or at least not the right kind of
properties (Kim 1993; Majors 2005; McPherson 2015; Klocksiem 2019).
For other criticisms of the Direct Argument, see Wedgwood (2007, Ch.
9) and Dunaway (2015).



The second argument from Supervenience is the Explanatory Argument.
This argument was developed by RM Hare and Simon Blackburn (Hare 1952;
Blackburn 1993), but the contemporary canonical formulation comes from
Tristram McPherson (2011). According to the Explanatory Argument,
supervenience is a striking phenomenon that must be explained. An
inability to explain supervenience counts strongly against a view.
Naturalists are well-positioned to explain supervenience: if moral
facts are natural facts, then, trivially, there can be no difference
in the moral facts without a difference in the natural facts. But
it's not clear how other views - particularly
non-naturalism, but perhaps also quasi-realist expressivism (Sturgeon
2009; Dreier 2015) - can explain supervenience.



The most obvious way to respond to the Explanatory Argument is to
offer an explanation of supervenience that doesn't trade on
naturalist assumptions. For example, Russ Shafer-Landau (2003, Ch 4)
and David Enoch (2011, Ch 6) have argued that supervenience can be
explained by the fact that there are moral laws. Ralf Bader (2017)
argues that there is a distinct sort of normative grounding relation
which both explains supervenience and doesn't entail property
identity (but see Morton (2020)). And Stephanie Leary (2017) has
argued that there are hybrid normative properties whose essences
explain supervenience (but see Faraci (2017); Toppinen (2018)).



A bolder response denies supervenience altogether. Supervenience is
widely accepted, but not uncontroversial (Roberts 2018). Sturgeon
(2009) accepts supervenience, but his reasons for doing so are
"parochial:" he is a naturalist and naturalism entails
supervenience. But Sturgeon sees no reason why anyone who's not
a naturalist should accept the doctrine. Several non-naturalists,
including, most notably, Gideon Rosen (2017b) and Kit Fine (2002),
have shared this assessment of the dialectical situation and rejected
Supervenience. Fine and Rosen argue that moral principles are not
*metaphysically* necessary but are, instead,
*normatively* necessary, where normative necessity is weaker
than metaphysical necessity but still quite strong. It's easy
for non-naturalists to explain the normative necessity of moral
principles, so non-naturalists can explain everything that needs to be
explained. If Supervenience is false, then both the Direct Argument
and the Explanatory Argument fail.


### 3.2 Arguments from Anti-Skepticism



A second family of arguments for naturalism are epistemic. Scientific
methods (broadly construed) are very powerful tools for coming to have
knowledge of the world so, if moral facts are the kinds of facts that
we can know about by scientific methods, then we have powerful tools
for obtaining moral knowledge. Non-naturalists, by contrast, say that
we know about moral facts via non-empirical methods, typically
intuition. This seems like a much less firm footing for our moral
knowledge than the scientific method. This is controversial, of
course. Intuitionist moral epistemology is popular (Huemer 2005;
Chudnoff 2013; Bengson, Cuneo, and Shafer-Landau 2020). And it's
not clear how we can use empirical methods to learn about moral facts
(although we'll look at some proposals in Sections 5-7)
(Shafer-Landau 2003, Ch 3). But it's widely believed that moral
naturalists have an easier time answering moral skeptics than
non-naturalists, and that's a reason to be a moral
naturalist.



Let's sharpen this point by looking at one influential family of
skeptical challenges: explanationist challenges. Explanationist
challenges begin from the premise that our moral beliefs are explained
by something other than the moral facts. What else? Different versions
of the explanationist challenge focus on different things. According
to the traditional version of the challenge from Gilbert Harman, our
moral beliefs are explained by our personal psychological attitudes
(Harman 1977, Ch 1). Other versions of the explanationist challenge
focus on more distant causes of our moral beliefs. Disagreement
arguments note that moral beliefs tend to cluster along cultural
lines, which suggests that our moral beliefs are explained by cultural
pressures (Mackie 1977, 37). Evolutionary debunking arguments posit
that our moral beliefs are ultimately explained by evolutionary
pressures (Joyce 2006; Street 2006). The common thought is that our
moral beliefs are not explained by the moral facts; they're
explained by a tangle of other naturalistic factors. Exactly why this
would lead to a skeptical conclusion is controversial, but many
philosophers think that explanationist challenges make a strong case
for skepticism. (For critical discussion, see, e.g., Enoch 2009;
FitzPatrick 2015; Vavova 2015; Schechter 2017).



Naturalists have an easy way to answer explanationist challenges. The
naturalist claims our moral beliefs are indeed explained by a tangle
of naturalist facts, but they hold that some of those natural facts
are the moral facts. For instance, Sturgeon argues that we think
Hitler was evil because Hitler was evil. Hitler's evil is a
natural feature of his character, and that feature both explains why
Hitler did the things that he did and why we judge him harshly as a
result (Sturgeon 1988). Similarly, David Copp argues that to be good
just is to be conducive to social cooperation. So when the
evolutionary debunker claims that we are naturally inclined, by
evolution, to think that things which are conducive to social
cooperation are good, this just amounts to the observation that we
judge that things are good because they're good (Copp 2008).
This is a compelling enough response that many advocates of
explanationist challenges construe them as challenges for
non-naturalists, but not for naturalists (Joyce 2006; Bedke 2009; Lutz
2018).


## 4. Objections to Naturalism



We've just seen that there is some reason to think that, if
there are any moral properties, those properties are natural. In this
section, we'll look at the most prominent objections to moral
naturalism.


### 4.1 The Open Question Argument



I said at the beginning of the article that contemporary metaethics
began with G.E. Moore's rejection of moral naturalism. The
argument that he deployed against naturalism is known as the Open
Question Argument (OQA). The OQA is perhaps the most influential
argument in metaethics, although today it is widely held to have
crippling flaws. Inevitably, this has inspired many critics of
naturalism to find ways to fix up or extend Moore's argument in
one way or another.



Explaining Moore's argument is complicated by the fact that his
original statement of the argument, in Sections 5-15
(particularly 13-14) of *Principia Ethica*, is famously
unclear. Moore himself admitted as much, in an unfinished forward to a
second edition (Sinclair 2019). I won't engage in Moore exegesis
here. I'll just give a version of the OQA that most contemporary
metaethicists would recognize as "the Open Question
Argument."



Moore's OQA takes aim at theories of the form "Everything
that is *N* is good," where '*N*' is a
bit of descriptive terminology that refers to a natural property, and
where claims like this are true in virtue of the meanings of
'good' and '*N*.' Moore is concerned
with goodness because he regards goodness as the most fundamental
moral concept, and holds that all moral inquiry is, in the end,
inquiry into what sorts of things are good. And he's concerned
with theories that are true in virtue of meaning because he believes
that there are true claims of the form "Everything that is
*N* is good" (for some potentially rather complicated
*N*). He just denies that it is analytic that being *N*
is the same thing as being good. "If I am right, then nobody can
foist upon us such an axiom as that 'Pleasure is the only
good' or that 'The good is the desired' on the
pretense that 'this is the very meaning of the
word.'" (Moore 1903, Sec 6.)



The OQA relies on a test for theories of the form "All
*A*s are *B*s." The first step is to turn the
statement of the theory into a question: "All *A*s are
*B*s" becomes "Given that *x* is *A*,
is *x* also *B*?" Some questions of this kind are
closed questions: one can know the answer simply by understanding the
question. "Given that *x* is a bachelor, is *x*
unmarried?" is a closed question. Anyone who understands the
meanings of 'bachelor' and 'unmarried' is in a
position to see that the answer to that question must be yes. Anyone
who expressed doubt about that question must be incompetent with
either the concept of *bachelor* or of *unmarried*. So
"All bachelors are unmarried" passes the test. That claim
is true in virtue of the meanings of 'bachelor' and
'unmarried,' and so being unmarried is part of the essence
of what it is to be a bachelor. Now consider the theory that pleasure
is goodness. We can ask "Granted that *x* is pleasurable,
is *x* good?" And this question is open. Someone can
understand it perfectly and still reasonably doubt the answer. So the
theory that pleasure is goodness fails the open question test;
pleasure cannot be identical to goodness. The argument generalizes:
For any natural property *N* and any moral property *M*,
"Granted that *x* is *N*, is *x*
*M*?" will be an open question. Therefore, no moral
property *M* is identical to any natural property
*N*.



The most obvious problem with this argument is that it's not
really an argument against naturalism at all. It is, instead, an
argument against analytic descriptivism. That is, it's an
argument against the claim that there is some descriptive term
'*N*' that necessarily refers to a moral property
*M* in virtue of the fact that there is a normative term
'*M*' that refers to *M*, and
'*N*' follows from a conceptual analysis of
'*M*' (Feldman 2005; Vessel 2020). But as we saw in
Section 2.1, analytic descriptivism is not the same thing as
naturalism. Some naturalists are synthetic descriptivists, who hold
that '*N*' necessarily refers to *M*, but
that this is established empirically rather than by conceptual
analysis (Brink 1989, Ch 6; Brink 2001). And one-term naturalists hold
that there is no descriptive term that necessarily refers to any moral
property (Sturgeon 2003; Vayrynen 2021). The OQA has no force
against either of these views. For these reasons, the common verdict
today among metaethicists is that - unless it can be
substantially modified or extended in some way - the OQA has no
force against naturalism.



In Moore's defense, even though he overlooked the possibility of
synthetic descriptivism and one-term naturalism, those views were not
yet developed at the time he first outlined the OQA. Indeed, they were
developed by naturalist philosophers who recognized the force of the
OQA against analytic descriptivism and so set out looking for other
naturalistic views that could evade the OQA. Rather than thinking of
these other naturalistic views as an oversight of Moore's, we
could just as easily give him credit for pointing others in their
direction.



Most philosophers think that the OQA does succeed in refuting analytic
descriptivism, yet analytic descriptivists have developed several
responses to the OQA. One traditional response, from William Frankena
(1939), says that the OQA begs the question. To an analytic
descriptivist who sincerely holds that, e.g., pleasure is the
definition of goodness, the question "Given that X is
pleasurable, is it good?" will seem closed. So whether that
question is open or closed is precisely what is at issue, so Moore
shouldn't claim that it is open without further argument.
Another traditional response appeals to the idea of the Paradox of
Analysis: if all analytic claims are obvious, then it's
impossible for there to be an interesting, informative conceptual
analysis. Since some conceptual analyses are interesting and
informative (we philosophers tell ourselves, desperately), not all
analytic claims are obvious. The OQA is a test of obvious analyticity,
but the correct definitions of moral terms might just be non-obvious
(Smith 1994, 37-39). Another response begins from the
observation that Moore gives only a handful of examples of
naturalistic analyses and generalizes to the conclusion that any
proposed analysis of moral terms must be wrong. That's an
awfully hasty generalization. It's not clear that this worry can
be addressed by providing any finite number of additional failed
analyses. If 'goodness' (e.g.) can be analyzed, it can
presumably be analyzed in one correct way, and all of the infinite
other possible analyses are false. So the hypothesis that
'goodness' can be analyzed predicts that there are an
infinite number of incorrect analyses of 'goodness.' A
hypothesis can't be refuted by data that it predicts, so even an
infinite number of incorrect analyses doesn't refute analytic
descriptivism (Finlay 2014, Ch 1).


### 4.2 The Normativity and Triviality Objections



Although Moore's version of the Open Question Argument today has
few defenders, there have been a number of recent attempts to
refashion it into a more compelling form. One popular version of the
Open Question Argument, called the Normativity Objection (see, e.g.,
Parfit 2011; Scanlon 2014), sidesteps questions about the cognitive
significance of moral and descriptive terminology and appeals to
considerations regarding the natures of natural and normative facts.
Moral facts are normative. They concern what is good and what we have
reasons or obligations to do. Natural facts - the kinds of facts
that scientists study - are facts about the innate physical
structure of the universe and the causal principles that govern the
interaction of matter. Those are obviously just two different kinds of
facts; moral facts are normative but natural facts are not. In trying
to give a naturalistic account of morality, naturalists forgot the
most important thing: that moral facts aren't purely facts about
the way the world *is*; they are facts about what
*matters*.



There are, generally, two ways in which a naturalist might respond to
this objection. First, a naturalist could say that moral facts
aren't essentially normative; it may be the case that we
typically have reasons to act morally, but reason-giving force is not
part of the essence of moral facts. That suggestion might have the
feeling of an absurdity - of course moral facts are the kinds of
things that provide reasons; if an action is morally required,
that's a good reason to do it! But according to some
"reforming definitions" of morality (Brandt 1979; Railton
1986), this thought is a defect in our conception of morality. It
would be more accurate and fruitful to define moral facts in terms
that are *typically* reason-providing but not
*necessarily* reason-providing.



The biggest problem for reforming definitions is that reason-giving
normativity *is* (arguably) essential to morality. As Joyce
(2000, Ch. 1) argues, normativity is a non-negotiable commitment of
our moral discourse. If the only kinds of facts that exist are
natural, and natural facts are not a source of reasons for everyone,
then this amounts to a proof that moral facts don't exist (see
also Luco 2016). Reformers may respond by calling into question
Joyce's notion of "non-negotiable" commitments. It
is controversial whether any of our concepts have commitments that are
non-negotiable in this way (compare Prinzing 2017). Reformers may also
reply by pointing out that they're not entirely giving up on
normativity. If moral facts are the kinds of facts that we typically
have reason to care about, and there are strong forces in human
society and psychology that lead us to care about moral facts, then
they're normative enough for all practical purposes.



The second way to respond to the Normativity Objection is to say that
normativity is itself a natural phenomenon. The most popular strategy
for substantiating natural normativity proceeds in two steps. First,
show that all normative concepts can be analyzed in terms of one,
fundamental normative concept. Second, show that that fundamental
normative concept picks out a natural property. There are a number of
ways that such an account could proceed: here are two recent,
influential examples:


* Mark Schroeder (2005; 2007) accepts the "buck-passing"
or "reasons first" account of normativity (Scanlon 1998),
which says that all normative concepts can be analyzed in terms of the
concept of a reason. Schroeder also accepts the "Humean"
theory of reasons (as a substantive, synthetic truth), which says
that, roughly, S has a reason to Ph just in case Ph-ing will
promote the satisfaction of one of S's desires. If the Humean
theory is correct, then being a reason is a natural property. And, if
all other moral facts are to be analyzed in terms of reasons, then all
moral facts are natural facts.
* Phillipa Foot (2001) accepts a "value first" account
of normativity, which says that goodness is the fundamental normative
concept. She also accepts a neo-Aristotelian account of goodness (see
Section 5 below for more on neo-Aristotelianism.) If
neo-Aristotelianism is correct, goodness is a natural property. And if
all moral facts are to be analyzed in terms of goodness, then all
moral facts are natural facts.



This two-step strategy is popular but controversial. Those moved by
the Open Question Argument and the Normativity Objection are skeptical
that the second step of the naturalizing strategy could ever be
completed. Non-naturalists doubt that it could ever be shown that the
fundamental normative concept picks out some natural property because
normative properties and natural properties just seem to obviously be
different kinds of properties. Wittgenstein claimed to "see
clearly, as it were in a flash of light, not only that no description
that I can think of would do to describe what I mean by absolute
value, but that I would reject every significant description that
anybody could possibly suggest, ab initio, on the ground of its
significance" (Wittgenstein 1965). David Enoch (2011) is more
pithy, saying simply that natural properties and normative properties
are *just too different* for any natural account of a
fundamental normative property to be satisfying.



But it's unclear what this "just too different"
intuition amounts to (Laskowski 2019). In what sense are the natural
and the normative "just too different?" Schroeder thinks
that the intuition has force only if there is "a perfectly
general single truth about which any reductive view would be forced
into error" (Schroeder 2005, 14). The existence of such a truth
would be the proof that the natural and normative are just too
different; without such a truth, the non-naturalist hasn't
really offered an argument against naturalism. But because all
normative claims conceptually reduce to claims about reasons, argues
Schroeder, there will be no such truth, provided that we have a
coherent account of the foundational notion of a reason. So a coherent
account of normative reasons can explain all normative claims. These
fundamental normative facts about reasons are themselves explained by
the natural facts to which reasons reduce. But because this reduction
of reasons will take the form of a synthetic reduction, there end up
being no conceptual connections between the normative and the natural.
This general lack of conceptual connections between the normative and
the natural is what explains the "just too different"
intuition, and it is fully compatible with moral naturalism as a
synthetic metaphysical truth (see also Copp 2020).



Schroeder's response may succeed in providing a
naturalist-friendly explanation of the "just too
different" intuition, but it seems strange to say that the
existence of numerous analytic relations between different normative
concepts, combined with a lack of analytic relations between normative
and natural concepts, supports the thesis that the normative is
natural. The lack of conceptual connections between the natural and
normative may be better explained by non-naturalism (Enoch 2011).



Derek Parfit's Triviality Objection (Parfit 2011) is another
contemporary extension of the Open Question Argument. If moral
naturalism is true, says Parfit, then it will be possible to make
moral claims and natural claims and have those two claims be about the
same fact. Parfit worries that if the two claims are about the same
fact, then those two claims must contain all the same information. And
a statement of equivalence between any two claims that contain the
same information must be trivial. But moral claims that describe the
relationships between moral facts and natural facts are not trivial at
all - they are highly substantive.



Derek Parfit's Triviality Objection (Parfit 2011) is another
contemporary extension of the Open Question Argument. If moral
naturalism is true, says Parfit, then it will be possible to make
moral claims and natural claims and have those two claims contain all
the same information. And a statement of equivalence between any two
claims that contain the same information must be trivial. But moral
claims that describe the relationships between moral facts and natural
facts are not trivial at all - they are highly substantive. So
moral naturalism is false. However, it is not clear that this
Triviality Objection is any more forceful than the Open Question
Argument. Parfit's central motivating thoughts are that
natural-moral identity claims are substantive rather than trivial, and
therefore moral claims concern a different kind of fact than natural
claims. These are exactly the central thoughts behind Moore's
Open Question Argument, and so naturalists to respond to this
objection in largely the same way that they respond to the Open
Question Argument. Naturalists typically respond by adopting a version
of synthetic naturalism, and arguing that moral-natural identities are
informative in the same way that other synthetic property identity
claims (like water = H2O) are (Copp 2017).



Having discussed moral naturalism in general terms, we'll now
examine three of the most popular naturalistic metaethical views in
detail. As we go, it will be worth keeping the normativity objection
in mind. A version of the normativity objection will end up being one
of the most pressing objections to all of these views.


## 5. Neo-Aristotelian Naturalism



Aristotelianism has had adherents since... well, since Aristotle.
Even in the dark times of the mid-20th century, when naturalism was in
disrepute, post-Moore, Aristotelians like Elizabeth Anscombe kept the
flame alive (Anscombe 1958). Neo-Aristotelianism has both ethical and
metaethical commitments. We'll primarily be looking at the
metaethical aspects of neo-Aristotelian naturalism, but first-order
ethics will make an appearance as well.



We can characterize Aristotelian naturalism by four major ideas. The
first is that there is no one property of goodness. The goodness of a
good toaster is different from the goodness of a good movie, which is
different from the goodness of a good time to dance, which is
different from the goodness of a good person. To be a good thing is to
be a good thing of its kind. The second is that this fact is mirrored
in our language. The semantics for goodness is attributive rather than
predicative (more on this shortly). The third is that the most
fundamental ethical concept is the concept of a good person. Good
actions are the actions a good person will do, good things are the
things that good people will desire or pursue, and good practical
reasoning is reasoning in the way that good people reason. And the
fourth is that the standards that make something good are derivable
from the nature of the kind of thing it is. So what makes someone a
good person is derivable from the kind of thing a human person is.
This implies that morality is derivable from biology - although
this biological conception of human goodness is quite controversial,
even among Aristotelians.



Let's start by looking what Aristotelians say about the
semantics of 'good.' Contemporary Aristotelians follow
Peter Geach (1956) in distinguishing between two different kinds of
adjective: attributive and predicative. The difference between the two
comes from whether they validate the following inference pattern:


1. *X* is an *F* *G*.
2. *X* is an *H*.
3. Therefore, *X* is an *F* *H*.



If *F* is a predicative adjective, that inference will be
valid. If *F* is an attributive adjective, then it won't.
To make this concrete, consider the following instances of this
schema:


4. Jerry is a brown mouse.
5. Jerry is an animal.
6. Therefore, Jerry is a brown animal.



4-6 is valid. If Jerry is a brown mouse, then he's a brown
animal. Therefore, 'brown' is a predicative adjective.
Predicative adjectives refer to the same property in all contexts.
Compare this to:


7. Jerry is a large mouse.
8. Jerry is an animal.
9. Therefore, Jerry is a large animal.



7-9 is not valid. A large mouse is still a very small animal.
Therefore, 'large' is an attributive adjective. The
meaning of an attributive adjective in any given context is determined
by the noun that it is modifying. "Large mouse" means
(something like) "Large for a mouse."



With this in mind, consider the following argument:


10. Frank is a good tennis player.
11. Frank is a husband and father.
12. Frank is a good husband and father.



This is clearly invalid. Frank might have a powerful serve and a
wicked backhand, yet neglect his family. This indicates that
'good' is attributive (although see Szabo 2001).
'Good' does not refer to the same property of goodness in
all contexts. Instead, 'good K' means something like
'good-for-a-K.'



Judith Jarvis Thomson has influentially expanded on Geach's
basic idea. According to Thomson, there is a property of being a good
*K* only if *K* is a goodness-fixing kind (Thomson 2008,
21). For instance, "knife" is a goodness-fixing kind;
thus, there is the property of being a good knife. Goodness need not
always be understood in terms of goodness-fixing kinds. Things can be
good in other respects, such as "good for use in making
cheesecake" or "good for Alfred" (Thomson 1997,
278). Thomson calls things that are good in this way
"good-modified." There is no such thing as "a good
smudge," full stop, because "smudge" is not a
goodness-fixing kind in the way "knife" is. But there
might be a smudge that is good for using in a Rorschach test, because
"being used in a Rorschach test" is a way that smudges can
be good-modified (Thomson 2008, 21-22).



Thomson holds that it makes no sense to ask whether an act is good or
not, because "act", like "smudge", is not a
goodness-fixing kind. Accordingly, acts can only be good-modified;
they can be good in some respect - e.g., a moral respect. Acts
are morally good when they spring from an agent's morally
virtuous traits. A moral virtue is any trait such that an individual
of a kind K is as morally good as a K can be only if it has that trait
(and it's possible for to either have or lack that trait)
(Thomson 2008, 79).



So what makes a person as good as a person can be? The fourth major
Aristotelian idea is that the standards of goodness for a thing are
determined by the kind of thing it is. But how can a thing's
*kind* determine the standards for that thing? The traditional
answer, from Aristotle, says that kinds of things have a particular
form, or shape. The form of hammers is just their hammer-shape. The
form of a thing determines its function: the function of a hammer is
to hammer because hammers are shaped in a way that makes them good for
hammering. And function thus determines the *telos* (purpose or
end) of the thing: hammers are for hammering, and a good hammer is one
that hammers well. All of this can be understood in unmysterious,
naturalistic terms. We can apply this same model to human beings. The
form of a human determines what the specific human function is. And a
good person is, therefore, someone who performs that function well by
satisfying the characteristic ends of human life. 



The most influential account of human ends comes from Rosalind
Hursthouse. Hursthouse says that human life is characterized by four
ends: survival, reproduction, characteristic enjoyment and freedom
from pain, and the good functioning of the group. Survival and
reproduction are common to all living things, including plants. But
the manner in which these ends should be pursued are characteristic of
the species. Penguins have one characteristic way of reproducing and
lions have another (Hursthouse 1999, Ch 9). The characteristically
human way of pursuing these four human ends is by the use of
rationality. Humans alone among the animals act not from mere
instinct, but from a rational capacity of deliberation and choice. So
good, "flourishing" humans are those who pursue the four
ends in accordance with reason. Like many other neo-Aristotelians,
Hursthouse uses the word "flourishing" as an English
translation of Aristotle's *eudaimonia,* since it nicely
captures the analogy with other kinds of living organism that is
central to Aristotelian naturalism. But 'flourishing'
might not be the best word, since it may misleadingly imply an
untroubled life (Foot 2001, Ch 6).



A common objection at this point is that the notion of an end or
*telos*, while central to Aristotle's conception of
biology, is much more controversial in a Darwinian biological paradigm
(Millum 2006; compare Moosavi 2022a). This is particularly true if we
are talking about the *telos* of an organism as a whole; many
philosophers of biology will still be happy to say that the purpose of
the heart is to pump blood, but it's not clear that it makes
sense to talk about the purpose of a human being. For this reason,
many neo-Aristotelians prefer to avoid (or at least de-emphasize) the
idea of a human *telos* and instead talk in terms of what
Michael Thompson has called "Aristotelian categoricals"
(Thompson 2008, Ch 4). These are claims like like "Oak trees
have deep, sturdy roots" or "Humans have 32 teeth."
Aristotelian categoricals are not necessarily true of all, or even
most, members of a species; most humans have less than 32 teeth
(Anscombe 1958). Rather, they describe something important about the
*nature*, or the characteristic form of life, of different
kinds of living things (McDowell 1998). They say what
"should" be the case for a member of a species, or what
will be true of an organism insofar as it is flourishing. In this way,
Aristotelian categoricals are both descriptive biological claims but
also, in a way, evaluative.



Aristotelian categoricals allow us to evaluate organisms in a
straightforwardly naturalistic way. An oak tree with deep, sturdy
roots is (at least in this respect) flourishing, while one without
deep, sturdy roots is defective. Similarly, then, a good person is
flourishing insofar as they participate in characteristically human
ways of life, and bad people are defective in the same sense that an
oak without deep, sturdy roots is defective. "A bad tree."
The only difference is that humans and oak trees participate in very
different ways of life. The aptness of the comparison is better
illustrated by looking at other social animals, like wolves. Wolves
hunt in packs; that is their characteristic way of life. A wolf that
hunts in a pack flourishes, while a wolf that hunts by itself is
defective. A good life for a wolf is partly a matter of cooperating
with others of its kind to achieve further ends which are constitutive
of a flourishing life (Foot 2001, 16). So, too, with humans. The
characteristic ways of life for any given thing are what we might call
the virtues of that thing; deep, sturdy roots are virtues in an oak.
The distinctively human virtues are the virtues that are particular to
human life, which is a social life governed by rational deliberation.
And those are just the traditional virtues of moral philosophy:
courage, humility, generosity, and so on (Foot 2001, Ch 5). Humans
with those virtues are, in that respect, flourishing. Those that lack
the virtues are defective.



Let's turn to some objections. First, consider the
Aristotelian's claim that goodness is an attributive adjective.
It's quite plausible that goodness functions like an attributive
adjective sometimes: a good tennis player might be a bad father. But
there might also be a predicative use of the word 'good.'
For instance, consider the idea of a "good state of
affairs." It is hard to give the 'good' in
"good state of affairs" an attributive reading: states of
affairs aren't what Thomson calls a good-fixing kind. Thomson
argues that this means that it's incoherent to say that there
could be such a thing as a good state of affairs; she takes this to be
a strong challenge to consequentialism (Thomson 2008, 62). But if the
notion of a good state of affairs is intelligible, perhaps
"good" sometimes serves as a predicative adjective that
refers to a property of (moral) goodness (Sturgeon 2010).



Second, whether we evaluate human organisms in terms of a
*telos* or a characteristic form of life, it's not clear
how these kinds of evaluations are relevant to ethics. Even if there
is a characteristic way of human life, why should we live that way
ourselves? What is *normative* about "natural
goodness" (Prinz 2009)? Living a characteristic human life might
be a very bad way to live. There are some characteristic ways of human
life that seem to be quite bad: for example, destroying the
environment, fighting ideological wars, and having a sense of altruism
that is limited to a relatively small circle of family and friends.
Neo-Aristotelians seem to assume a rather rosy picture of human nature
that's hard to square with a serious study of history or
sociology (Williams 1972; Millgram 2009).



Neo-Aristotelians typically answer this worry by appealing to the role
of reason (Hacker-Wright 2009; Lott 2012; Jordan 2020). The supreme
human virtue that characterizes a flourishing human life is
*phronesis*, the virtue of being able to reason well about how
to act (Hursthouse 1999, Ch 4). So fighting ideological wars is not
characteristic of human life because it's not reasonable to
fight ideological wars; that's not how a good person, one with
*phronesis*, would act. This way of operationalizing
Aristotelianism throws out the idea that discerning natural goodness
is a matter of applied biology (Hursthouse 1999, 178-191). The
characteristic form of human life is defined ethically, not
biologically (Nussbaum 1995).



One might well worry that this abandons the naturalistic character of
Aristotelianism. Aristotelians typically reply that to be a good
person is just to be a certain sort of human organism with certain
mental characteristics (which amounts to having a brain that is
functionally organized in a certain way). So (recalling our
distinctions from Section 1), while neo-Aristotelians accept Property
Naturalism and most accept Fact Naturalism, many end up rejecting
Methodological Naturalism (Hursthouse 1999, Ch 10; Moosavi 2022b). But
John McDowell has argued that the human virtues are
"natural" only insofar as they relate to the
"nature" of human beings, and human nature is not a
subject for scientific investigation (McDowell 1998). Micah Lott has
argued that neo-Aristotelians should give up on pretensions to
naturalism (Lott 2020).



Three further problems linger. First, appealing to practical reason to
solve the problem of normativity seems to undermine the core
Aristotelian idea that we can define a good person in terms of what is
distinctive of human life. Kant argued that Aristotle was wrong to
ground ethics in the form of a human life, since what matters for
ethics is the form of pure practical reason. Contemporary
Aristotelianism seems to concede this point to Kant (Woodcock 2018;
but see Jordan 2020 or McKracken 2021). Second, neo-Aristotelianism
looks circular. One of the main ideas of Aristotelianism is that the
goodness of a good person is the fundamental moral concept, but if we
define a good person in ethical terms, we've gone in a circle.
Brown (2016) responds that a good person is defined in teleological
rather than ethical terms, but this just raises the question of how we
define teleology. Biological definitions seem inadequate, but
normative definitions make the account circular once again. Third,
even if the circularity concerns can be answered, we might worry that
a larger epistemological problem remains. How can we identify virtuous
agents? Abandoning Methodological Naturalism might create more
problems than it solves (but see Jordan 2016).


## 6. Cornell Realism



If moral naturalism is the view that moral facts are the kinds of
facts that can be investigated in a broadly scientific way, then no
view captures the spirit of naturalism better than Cornell realism.
Cornell realism was developed in the 1980s by Richard Boyd (1988),
David Brink (1986), Nicholas Sturgeon (1985), and Peter Railton
(1986a; 1986b); the view gets its name from the fact that Boyd, Brink,
and Sturgeon were working or studying at Cornell University at the
time. It is a comprehensive metaethical system, with interrelated
linguistic, metaphysical, and epistemological commitments, that
deliberately mirrors scientific methodology in ethics as closely as
possible.



It might seem odd to suggest that we can know things about morality by
using scientific methodology. Scientific methods are all, ultimately,
grounded in an epistemology of observation. And as Gilbert Harman
(1977, Ch. 1) famously argued, it does not seem that we can observe
moral facts in anything like the same way that we can observe other
kinds of natural facts. It's rather obvious how we can have
empirical knowledge of natural properties such as redness or
roundness; they are directly observable. But goodness doesn't
seem to be directly observable, and that looks like an important
disanalogy between moral properties and natural properties.



But not all natural properties are directly observable. Some kinds of
natural properties are complex, and knowable only through the
functional role they occupy. Consider, for instance, the property of
being healthy. Being healthy isn't like being red; there's
no one way that healthy people look. Of course, there may be some
characteristic visual signs of healthiness - rosy cheeks, a
spring in one's step - but these visual signs are neither
necessary nor sufficient for healthiness. These directly observable
properties are only indications of healthiness. Healthiness is a
complex natural property, wholly constituted by an organism's
body being in the "proper" configuration, with a robust
causal profile. There are many things that can cause or impede health
by their presence or absence: food, water, disease, etc. And there are
many things that will result from health in typical circumstances:
energy, long life, etc. Rosy cheeks and a spring in one's step
are indications of healthiness because these are properties that are
- typically - caused by health. Our awareness of the
causal profile of healthiness thus gives us a way of figuring out
which things have or do not have the complex property of
healthiness.



Cornell realists hold that goodness is exactly like healthiness in all
of these ways (Boyd 1988). Like healthiness, goodness is a complex
natural property that is not directly observable, but nonetheless has
a robust causal profile. Like "healthiness,"
"goodness" is not synonymous with any simpler empirical
description. Instead, "goodness" describes the
functionally complex natural property that is the effect of certain
characteristic causes, and the cause of certain characteristic
effects. Many different things contribute to or detract from goodness
- things like pleasure or pain, honesty or untruthfulness
- and there are many things that will result from goodness in
typical circumstances - things like human flourishing, or
political peace. Because goodness is a natural property with a complex
causal profile, the property of goodness can enter into explanatory
relations. Thus, contra Harman, it is possible for goodness to explain
our observations (Sturgeon 1985). We can, accordingly, observe whether
something is good by looking for indications of goodness. This is
exactly the same way that we observe whether something is healthy.



Another way that goodness is like healthiness is that both are
multiply realizable. We could, perhaps, give a more or less complete
description of what it takes for a human body to be healthy, although
such a description might be quite long and complicated. But it's
also possible that aliens with a very different biology exist, and for
those aliens to be healthy, even though a healthy alien body is
nothing like a healthy human body. But despite their radical physical
differences, both a healthy alien and a healthy human are healthy. The
same might be true of goodness, or other moral properties. As a
natural property, any particular instance of goodness is fully
constituted by a complex of more fundamental physical properties. But
goodness might be constituted by an indefinitely large number of
radically distinct physical configurations: the goodness of a promise
kept is quite different from the goodness of a delicious and
nutritious meal. This motivates the Cornell realists to call
themselves non-reductive naturalists (by which they mean that they are
one-term naturalists rather than descriptivists). Goodness is
realizable in too many physical structures to give a usable definition
of morality in descriptive terms.



The great asset of Cornell realism is that it directly adopts widely
accepted views about the nature of natural properties and scientific
knowledge in order to answer the foundational questions of moral
metaphysics and moral epistemology. What are moral properties? Highly
complex natural properties, multiply realizable in more fundamental
structures, and individuated by their causal profiles. Are there,
generally, properties like this? Yes; these are known as
"homeostatic cluster properties." Healthiness is one;
moral properties are properties like that. How do we know about moral
properties? By looking for directly observable properties that are
characteristically functionally upstream or downstream from the moral
property that we are interested in (provided that we have justified
background beliefs about the functional roles of moral properties). Do
we, generally, have knowledge like this? Yes: this is how we have
scientific knowledge; moral knowledge is knowledge like that. In this
way, the theoretical resources of scientific realism also turn out to
support moral realism (Boyd 1988).



A skeptic might object that it's impossible to have justified
background beliefs about the functional profile of moral properties.
But this objection would prove too much. We are entitled to rely on
background beliefs in moral theory development because we're
entitled to do so in science, generally (Boyd 1988, 189-191).
Our theories and background beliefs are justified together, by their
overall coherence and empirical adequacy, in both science and
ethics.



It is not essential to Cornell realism that goodness be identified
with any particular complex natural property - different Cornell
realists have different first-order normative commitments. The most
influential of these accounts is due to Railton (1986a; 1986b).
Railton, like Thomson, holds that moral goodness is defined in terms
of what is non-morally good for agents. Whereas Thomson, as a
neo-Aristotelian, defines what is good for a human in terms of human
biology, Railton defines non-moral goodness for an agent as what a
fully-informed counterpart would advise us to desire, or, (perhaps)
equivalently, what a fully-informed counterpart of ourselves would
desire if they were in our actual position (see also Brandt 1979;
Smith 1994). To illustrate, Railton asks us to imagine a traveler,
Lonnie, who feels terrible because he is badly dehydrated. Lonnie does
not know that he is dehydrated, and so is not taking appropriate steps
to make himself feel better. But imagine a fully-informed version of
Lonnie - "Lonnie-Plus" - who knows about his
dehydration and knows that drinking clear liquids will make him feel
better. Lonnie-Plus, who (like Lonnie) desires to feel better but who
(unlike Lonnie) knows the best means to that end, would recommend that
Lonnie drink clear fluids, and would drink clear fluids himself if he
were in Lonnie's position. The fact that Lonnie-Plus would
advise Lonnie to want to to drink clear fluids means that drinking
clear fluids is good for Lonnie. This is not a relativist view of
goodness, because the fact that Lonnie-Plus would choose to drink
clear liquids is determined by Lonnie's circumstances and
constitution, and facts about Lonnie's circumstances and
constitution are objective facts. In general: the complex natural
property of being good for an agent is identical to the complex
natural property that agent's fully-informed counterpart would
choose. This makes goodness "objective, though relational"
(Railton 1986b, 167).



This account is highly controversial. Railton's case of
Lonnie-Plus presents a counterpart who knows just a few more salient
bits of information than Lonnie. But a counterpart who is truly
*fully-*informed will know *vastly* more than we
ourselves do, and would, accordingly, be quite different from us. A
fully-informed counterpart might be suicidally depressed, or made
neurotic by their full awareness of all the oddities and dangers in
the world, or might in some other way have been driven quite mad by
the process of becoming omniscient. It's far from clear what a
fully informed person would desire, and, given that fully-informed
individuals are so radically different from ourselves, it's not
clear why we should think that the advice of such an agent would have
anything to do with our own personal well-being (Loeb 1995). It might
also be impossible to be fully-informed in this way. It's
plausible that our knowledge affects the nature of our experiences,
and so a "fully-informed" agent would be incapable of
knowing what it is like to have experiences in a condition of
ignorance, and thus could not be truly fully informed (Sobel 1994;
Rosati 1995). We might also worry that full information accounts get
things backwards; advice attends to our interests, our interests
don't attend to advice, even ideal advice (see Risberg 2018 and
citations therein). Railton heads off this objection by denying that
personal good *depends on* an ideal advisor's advice:
"the existence of an individual's objective interest can
explain why his ideally informed self would pick out for his
less-informed self a given objectified subjective interest, but not
*vice versa*" (Railton 1986b, fn 17). This answers the
worry, but leaves us somewhat adrift. If the advice of a
fully-informed counterpart doesn't make a certain complex of
natural properties count as good for an agent, what *does*?



With this account of personal, non-moral goodness in hand, Railton
then defines a moral standard as a standard that takes all
agents' interests equally into account. To act rightly is to act
in accordance with this standard. Railton's moral standard is
"consequentialist, aggregative, and maximizing, [but it] is not
equivalent to classical utilitarianism," since Railton does not
assume that personal, non-moral goodness consists in happiness
(Railton 1986, fn. 31). This moral standard has explanatory power; for
instance, if a society does not take the interests of all into
account, it might be more prone to revolution, and so a revolution in
an immoral society might be explained by that immorality. Because the
moral standard is one that takes the interests of all into account,
the right thing for an agent to do may fail to serve her interests.
Assuming that practical reasons are grounded solely in self-interest
(as Railton does), people who don't care about the moral
standard might have no reason to act morally. As we saw in Section
4.2, Railton accepts a "reforming definition" of morality
that sacrifices the intrinsic normativity of moral standards. As we
also saw in Section 4.2, many consider this to be an unacceptable
consequence of the view.



There may, in practice, be substantial overlap between the
metaphysical commitments of neo-Aristotelianism and Cornell realism.
Cornell realists say that the good is a certain higher-order natural
property. Neo-Aristotelians say that goodness has something to do with
human flourishing, which is also a higher-order natural property. Both
Cornell realists (Boyd) and neo-Aristotelians (Thomson) have found the
analogy with healthiness illuminating when explaining the nature of
moral properties (see also Bloomfield 2001). So Cornell realists and
neo-Aristotelians do tend to be similar in the way that they conceive
of normative properties. But they differ with respect to what they say
about language.



While neo-Aristotelians favor an attributive semantics for
'good,' Cornell realists accept causal regulation
semantics for moral terms, which is the view that moral terms refer to
whatever property causally regulates their use. Adopting causal
regulation semantics is a sensible thing for the Cornell realists to
do, for two reasons. First, it continues their foundational commitment
to treating moral properties as natural properties that we know and
talk about in the same way that we know and talk about other natural
properties. Causal regulation semantics are the standard semantic
account for natural kind terms. And second, it helps them evade the
Open Question Argument (Brink 2001). According to causal regulation
semantics, moral terms cannot be defined in any verbal way. They
simply refer to the (complex higher-order natural) property that
causally regulates their use. This makes Cornell realism a form of
synthetic naturalism. As we saw in 1.2, Moore's Open Question
Argument shows, at most, that analytic descriptivism is false.



But the Cornell realist's semantics is also the source of the
most influential objection to Cornell realism. According to this
objection - Horgan and Timmons's Moral Twin Earth
Objection (Horgan and Timmons 1991) - we do not use moral terms
in the way that the Cornell realist predicts. To understand the Moral
Twin Earth Objection, we need to first understand how causal
regulation semantics are supposed to work. The following thought
experiment, from Putnam (1975), has been highly influential: Imagine a
world - Twin Earth - where there is no H2O, but
there is another substance called XYZ. This substance XYZ, while
distinct from H2O, fills the rivers and lakes, is clear and
tasteless, etc. XYZ even has the property of being called
'water' - when residents of Twin Earth fill up a
glass with XYZ from the tap, they will say "I have a cup of
water." Yet for all this, we would not say that Twin Earth is a
planet where water is XYZ. We would say that this is a planet where
there is no water. There is, instead, another substance - XYZ
- that plays the same functional role. Yet when the person on
Twin Earth fills a cup from the tap and declares "I have a cup
of water", we shouldn't say they're mistaken. What
could account for that? Putnam argues that the word
'water' just means something different on Twin Earth than
it does in the actual world. In the actual world, 'water'
means H2O because, in the actual world, H2O is
the stuff that causally regulates our use of the term
'water.' But on Twin Earth, 'water' means XYZ
because, on Twin Earth, it is XYZ that causally regulates Twin
Earthlings use of the term 'water.' That is why the word
'water' literally means something different on Twin Earth
than it does on Earth.



According to the Moral Twin Earth Objection, things don't work
this way for moral terms. Imagine a world - Moral Twin Earth
- that is exactly like the actual world, except on Moral Twin
Earth, people's use of moral terminology is causally regulated
by different properties from those in the actual world. People use
moral terminology to praise and blame and to guide action, but they
take different kinds of actions to be worthy of praise or blame and
they guide their actions in different ways. Thus, if causal regulation
semantics is true for moral terms, the word 'right'
literally means something different on Moral Twin Earth than it does
in the real world - this is the intuition that drives
Putnam's original Twin Earth case. But we do not have the same
judgment about how people use moral language on Moral Twin Earth! If
people on Moral Twin Earth take different actions to be worthy of
praise or blame, we don't conclude that our words
'right' and 'wrong' mean different things. We
conclude that there is a substantive moral disagreement between the
denizens of Moral Twin Earth and the people in our world, and that
such disagreement is possible only because we and the Twin Earthers
mean the same thing by our moral terms. Horgan and Timmons argue that
this proves that moral terms like 'right' and
'wrong' do not refer to whatever it is that causally
regulates their use. So much the worse for Cornell realism. See Copp
(2000), Dowell (2016), Dunaway and McPherson (2016), and Vayrynen
(2018) for recent criticisms of this argument. Wisdom (2021)
criticizes the whole debate on the grounds that our intuitions about
Twin Earth and Moral Twin Earth are not stable enough to draw any
meaningful conclusions one way or the other.



The deep problem here is that causal regulation semantics implies a
kind of relativism. Indeed, some relativists, like Prinz (2007) and
Wong (2006), have argued that their view follows from the Cornell
realists' empirical methodology and moral semantics. If words
refer to whatever causally regulates their use, and the same word is
regulated by different things in different communities, then that word
refers to different things in different communities. So if
'wrong' refers to whatever causally regulates its use, and
if two communities have a word 'wrong' that is causally
regulated by different things, then 'wrong' means
different things in those communities. This saddles Cornell realists
with a classical problem for relativism. If 'wrong' just
means something like 'whatever my community disapproves
of,' as the relativist says, then "My community
disapproves of this act, but they shouldn't, because
there's nothing wrong with it at all" is
self-contradictory. But that's not self-contradictory; so much
the worse for relativism (see, e.g., Schroeder 2010, Ch 1). Similarly,
if words refer to whatever causally regulates their use within a
community, then "This action regulates the use of the term
'wrong' in my community, but it shouldn't, since
there's nothing wrong about that action" would be
self-contradictory. But that's not self-contradictory; so much
the worse for Cornell realism (Sinhababu 2019).



One might think that Cornell realists can respond by offering a new
account of moral language. But this response faces difficulties on two
fronts. First, causal regulation semantics is the Cornell
realists' way of avoiding a commitment to analytic naturalism
and the accompanying Open Question Argument. If the causal reference
theory is false for moral terms, the naturalist may be forced to
accept a theory of moral semantics that would re-introduce the Open
Question Argument. Second, the causal reference theory for moral
language is essential to the Cornell realists' methodological
and epistemological commitments. If moral goodness is the thing that
regulates our use of moral terminology, then the terms of our
empirical investigation are simple: we just investigate what regulates
the use of our moral language. But if the moral facts are not
(necessarily) the facts that regulate the use of our moral language,
then we need a new methodology for moral investigation.



Because of this, the Moral Twin Earth objection is often presented as
a kind of extension of Moore's Open Question Argument. The Open
Question Argument is, in Moore's formulation, an attack on the
idea that there can be analytic natural-normative property identity
claims. But in a larger sense, the Open Question Argument picks out a
kind of epistemic shortcoming for moral naturalists. Moral naturalists
are committed to the idea that moral facts are a kind of natural fact
- but which natural facts are the moral facts? More simply, how
do we know good from bad? If moral claims are synonymous with certain
natural claims, we can know by conceptual analysis which things are
good. And if moral facts are the facts that causally regulate our use
of moral terminology, that provides us with another way of
investigating which facts are the moral facts. But if neither of those
stories is available, it seems that we have no way of identifying
which natural facts are the moral ones (Huemer 2005, chapter 4; Bedke
2012). This would be a serious methodological problem for moral
naturalists, and would also mark a critical disanalogy between moral
epistemology and scientific epistemology. This disanalogy would be
crippling to Cornell realists, who hold that there is no such
disanalogy.


## 7. Jackson's Analytic Functionalism



The final version of naturalism that we'll look at is Frank
Jackson's moral functionalism. Jackson is an analytic
descriptivist. While his is not the only contemporary version of
analytic descriptivism (see Smith 1994; Finlay 2014; Rawlette 2020),
it is the most influential. This view is typically described as
Jackson's, and the canonical statement of the view comes from
his book *From Metaphysics to Ethics*, though many of the ideas
in that book were developed with Philip Pettit (Jackson and Pettit
1995).



As we saw in Section 3.1, Jackson endorses the Direct Argument from
supervenience to naturalism. Because moral facts supervene on natural
facts, they are identical to natural facts. (Jackson talks about
"descriptive" facts rather than "natural"
facts, but I'll continue to use "natural" for the
sake of consistency.) The problem now is to say which natural facts
the moral facts supervene on and are therefore identical to. Jackson
calls this the "location problem." The location problem
isn't unique to ethics. Jackson expresses sympathy for
physicalism, the view that we could, in principle, give a complete
account of everything that exists in terms of the kinds of things that
physics does (or could) tell us about. Everything else that exists
supervenes on (and is therefore identical to) complexes of these
fundamental physical things. But which complexes of fundamental
physical things are the various non-fundamental things identical to?
Location problems abound. Solving them is the task of "serious
metaphysics" (Jackson 1998, 1-8).



So how can we solve location problems? What is the method of serious
metaphysics? The first step is conceptual analysis. If we want to know
what the Fs are, we need to have some idea of what we're talking
about when we're talking about "the Fs," and this
understanding will frame our subsequent investigation. The first step
in figuring out that water is H2O was understanding that
water is the clear, tasteless stuff that fills the rivers and lakes
and falls from the sky as rain, rather than the intoxicating stuff
found in beer, wine, and liquor. If you thought that water was the
intoxicating stuff in wine, you'd end up drawing a very
different - and incorrect - conclusion about the
composition of water (Jackson 1998, 28-31ff).



But wait! Putnam's Twin Earth thought experiment is supposed to
show that we can't discover the meaning of 'water'
by a process of conceptual analysis; the people on Twin Earth have the
same concept of 'water' as we do, but their word means
something different. Jackson responds that Putnam and his followers
have drawn the wrong lesson from the Twin Earth case. The Twin Earth
thought experiment doesn't show us that the concept of water
can't be analyzed; it shows that the concept can be analyzed,
since the Twin Earth thought experiment is itself a nice bit of
conceptual analysis. Twin Earth - and all other thought
experiments - are nothing more than ways to elicit intuitions
about how to deploy our concepts in a variety of counterfactual
circumstances. The intuitions that we elicit from thought experiments
are the stuff that conceptual analyses are made of. Putnam's
conclusion that 'water' refers to whatever causally
regulates the use of the term 'water' within a linguistic
community is itself a partial analysis of the concept of water
(Jackson 1998, 39-79). Of course, merely having a conceptual
analysis like this in hand is not the end of our investigation. Now
that we know what we're looking for, empirical investigation
takes over and we investigate what the stuff is that causally
regulates the use of the term 'water' within our
linguistic community. It turns out that that stuff is H2O.
That's how we solved the location problem for
'water.'



Now we have a general outline for how to solve location problems.
First, consider cases where we would, on reflection, deploy some
concept (e.g. 'water.') The result of this reflection will
be some set of platitudes about that concept. Next, we turn this set
of platitudes into a "Ramsay sentence." Take every
instance of the word 'water' (or whatever), and replace it
with a variable, X. So instead of "Water falls from the sky as
rain," we will have a collection of sentences that say things
like "X falls from the sky as rain." This collection of
Ramsay sentences is a description of a functional role; in this case,
the water-role. Finally, we empirically investigate what, if anything,
fulfills that role. We know that water is H2O because we
found, through empirical investigation, that H2O is the
stuff that satisfies the water-role. In general, we know what Fs are
by using conceptual analysis to figure out what the F-role is, and
then empirically investigating what, if anything, satisfies the F-role
(Jackson 1998, Ch 2-3).



We can perform this process to solve the location problem in ethics.
Begin with some moral concept, say "goodness." Then
consider a variety of cases where we would judge that something is
good. The result will be some set of platitudes about goodness. We can
then take those platitudes about goodness and turn them into a Ramsay
sentence which describes the goodness-role. Finally, we investigate
what, if anything, satisfies the goodness-role. That thing is goodness
(Jackson 1998, Ch 5-6).



What about multiple realizability? Jackson is attempting to provide a
conceptual analysis of our moral concepts, but the Cornell realists
thought that no such analysis is possible in part because goodness
(e.g.) is realizable in a large number of very different things.
Jackson is unconcerned by this. If goodness supervenes on a large
number of different descriptive properties, then goodness is identical
to the disjunction of all of those descriptive properties on which it
supervenes. Goodness might be identical to a disjunction -
perhaps an infinitely large disjunction! - of other natural
properties (see also Sinhababu 2018).



Many have found the suggestion that goodness is identical to an
infinite disjunction of natural properties to be metaphysically and
epistemologically suspicious. Can an infinite disjunction of natural
properties really be a property? And how could we have knowledge of an
ugly gerrymandered property? Jackson replies that *excessively*
disjunctive properties are suspect, because they cannot play a causal
role (Jackson 1998, 106). But not all disjunctive properties -
even infinitely disjunctive properties - are excessively
disjunctive. Consider the property of baldness. Baldness supervenes on
(and is therefore identical to) having a certain distribution of hair
on one's head. Well-known vagueness concerns about the predicate
'bald' may prevent us from giving a more compact
description of what it takes for someone to be bald. But there is some
large - perhaps infinitely large - set of hair
distributions which we would, on reflection, definitely consider to be
bald. Baldness is therefore identical to an infinitely large
disjunction of hair distributions. But that doesn't mean that
there's anything metaphysically or epistemically weird about
being bald. Many people are bald, many claims to the effect that
someone is bald are true, and in most cases it is not particularly
difficult to ascertain whether or not someone is bald. Jackson urges
us to say precisely the same thing about moral properties (124).



A second worry: When we assemble the platitudes about our concept of
"goodness," we will find that many of them implicate other
moral concepts. "If something is good, then you have a reason to
pursue it." "Virtuous character traits are good."
And so on. So we can't analyze the concept of goodness into
platitudes and then investigate what satisfies those platitudes, since
many of those platitudes will concern moral concepts that are equally
in need of analysis. Jackson's solution to this problem is to
analyze all of the moral concepts together. Take all of the platitudes
concerning goodness or value or wrongness or virtue, etc. Replace
every instance of "good" with a variable (g), replace
every instance of "value" with another variable (v),
replace every instance of "wrong" with another variable
(w), etc. The result is the functional role description of the
*network* of our moral concepts. Goodness and value and
wrongness are then the g, the v, and the w (etc.) that satisfy all of
the platitudes concerning g, v, and w (etc.).



A final worry: Which platitudes are we to select as the platitudes
that appear in our analysis? The ones that we endorse on reflection?
But who is the "we" who would endorse these platitudes on
reflection? How much reflection must we undergo? Jackson answers this
worry by appeal to the concept of a *mature folk morality*. A
folk morality is "the network of moral opinions, intuitions,
principles and concepts whose mastery is part and parcel of having a
sense of what is right and wrong, and of being able to engage in
meaningful debate about what ought to be done" (130). This folk
morality is then revised by hunting out inconsistencies within
one's moral commitments and engaging in moral discussion with
others, identifying disagreements, and hammering out any differences.
The resulting mature moral theory will be both individually and
interpersonally coherent. That's the final statement of the
view: The moral properties are whatever satisfies the network analysis
of the platitudes that make up mature folk morality.



Jackson's appeal to a mature folk morality is his main ward
against the Open Question Argument. To ask "*X* is
pleasurable, but is *X* good?" is, in effect, to ask
whether "Pleasure is good" is one of the platitudes that
will feature in our mature folk morality. But we don't have a
mature folk morality yet - we may not have one for a very long
time - and we have no way of knowing at this point what
platitudes will feature in it. Of course the question remains
open.



The fact that we don't know what the mature folk morality looks
like also shows that Jackson's idea of an infinitely disjunctive
property isn't a core commitment of the view. If our mature folk
morality is a vast, heterogeneous collection of principles and cases,
then only an infinitely disjunctive property could satisfy it. But our
mature folk morality could well be simple and compact. Whether we end
up with a compact formulation or an infinite disjunction depends on
the outcome of a process we have not yet seen the end of.



Now to some harder objections. One objection holds that
Jackson's view isn't really a version of analytic
naturalism, because the process of refining our mature folk morality
will be the result of not just moral discussion and reflection, but
also our observations of the real world (Lane 2018). Relatedly, one
might worry whether the platitudes of mature folk morality are really
conceptual truths. Someone might disagree with a mature consensus not
as a result of conceptual confusion but as a matter of genuine moral
disagreement (Zangwill 2000).



A second objection concerns how we should understand
"mature" folk morality. We don't want any endpoint
of moral theorizing to count as "mature;" if mature folk
morality is just the theory we end up with in the future, whatever
that might be, then why should we care about it? Maybe people in the
future will have the wrong moral beliefs! But if we define maturity in
normative terms, as the outcome of a good process of deliberation (or
something similar), Jackson hasn't really succeeded in providing
the reductive naturalistic account of normativity that he was hoping
for (Yablo 2000).



We might also worry that no mature folk morality will ever emerge. If
moral disagreement persists into the indefinite future, just as it has
persisted throughout human history, there is no mature folk morality
and thus no set of platitudes that determines the moral facts. Jackson
concedes that this is a real problem: if there is no convergence in
moral attitudes, his methodology would imply moral relativism. He can
only offer hope that convergence will occur some day (137-8).
And so Jackson's ambitious metaethical project turns out to rest
on an appeal to optimism.