## 1. The Naturalistic Fallacy




Moore famously claimed that naturalists were guilty of what he called
the "naturalistic fallacy." In particular, Moore accused
anyone who infers that *X* is good from any proposition
about *X*'s natural properties of having committed the
naturalistic fallacy. Assuming that being pleasant is a natural
property, for example, someone who infers that drinking beer is good
from the premise that drinking beer is pleasant is supposed to have
committed the naturalistic fallacy. The intuitive idea is that
evaluative conclusions require at least one evaluative
premise--purely factual premises about the naturalistic features
of things do not entail or even support evaluative conclusions. Moore
himself focused on goodness, but if the argument works for goodness
then it seems likely to generalize to other moral properties.




Somewhat surprisingly, Moore in effect also argues that most forms
of non-naturalism are also guilty of what he calls the naturalistic
fallacy. In particular, he argues that so-called "metaphysical ethics,"
according to which goodness is a non-natural property existing in
"supersensible reality" also are guilty of the naturalistic fallacy.
So, for example, a view according to which goodness is the property of
being commanded by God where God is understood as existing outside of
Nature is also charged with having committed the naturalistic fallacy.
This suggests that the naturalistic fallacy is not well named in that
it is not specifically a problem for naturalists, and Moore admits as
much. If the point were purely terminological then it would be trifling
but an important philosophical point is at stake here. The real force
of Moore's argument is supposed to be that attempts to reduce moral
properties to anything else are doomed to fail. This is why Moore's own
view of goodness as *sui generis* and irreducible is supposed to
avoid the naturalistic fallacy. Since the
reductionist/anti-reductionist distinction cuts across the
naturalist/non-naturalist distinction (properly understood), this
suggests that the real target of Moore's argument is reductionism
rather than naturalism. Admittedly, if Moore is right then at least
reductionist forms of naturalism fall prey to the naturalistic fallacy
and it is therefore still relevant to the debate over naturalism and
non-naturalism. However, the non-naturalist will need a separate
argument against those naturalists who hold that moral properties
natural but irreducible. As noted in the Introduction, Moore seems to
have ignored the distinction between naturalism and reductionism and
this is one important case in which that mistake seems important.




The naturalistic fallacy is very poorly named indeed (a point also
made by Bernard Williams; see Williams 1985: 121-122). For not
only is it not especially a problem for naturalists, it is also not
really a fallacy even if Moore is right that it embodies a mistake of
some kind. For it is highly uncharitable to charge anyone who
advances the sorts of arguments to which Moore alludes as having
committed a logical fallacy. Rather, charity demands that we interpret
such arguments as enthymematic, and usually this is easy enough. For
example, we should understand '*X* is pleasant,
therefore *X* is good' as an enthymeme whose suppressed
premise is 'Whatever is pleasant is good'. Nor must the
non-naturalist even quarrel with such a suppressed premise. One can
allow that goodness is itself a non-natural property but grant that
all pleasant things necessarily have that non-natural property. What
the non-naturalist must reject is the thesis that such suppressed
premises are true in virtue of the identity of goodness with the
natural property in question (being pleasant, in this case). So the
so-called naturalistic fallacy is no fallacy at all. Rather, if Moore
is right then the so-called naturalistic fallacy actually embodies a
mistaken belief about the reducibility of goodness, perhaps the belief
that 'good' just means 'pleasant' (or
whatever). However, to suppose that whenever someone is metaphysically
or semantically confused he is guilty of a 'fallacy' robs
the term of its more standard and useful meaning. This point was made
very clearly by W.K. Frankena in a landmark article published
in *Mind* (Frankena 1939).




Finally, as Frankena also nicely pointed out, it cannot be assumed
at the outset that what Moore calls the naturalistic fallacy really is
a mistake of any kind. For certain naturalists could then reasonably
complain that the central question has been begged. The naturalist
proposes a certain kind of definition of some moral term and the
non-naturalist then simply asserts that anyone who thinks such
definitions are possible is mistaken. If we want to find a
non-question-begging argument against naturalism then we must look
beyond the so-called "naturalistic fallacy."


## 2. The Open Question Argument




Moore's "Open Question Argument" for the conclusion that goodness is a
non-natural property is closely related to his worries about the
naturalistic fallacy. Consider any proposed naturalistic analysis *N* of
a moral predicate *M*. The Open Question Argument maintains that it will
always be possible for someone competent with moral discourse without
conceptual confusion to grant that something is *N* but still wonder
whether it is really *M*. Whether goodness is co-instantiated with any
natural property or set of natural properties is in this sense always
a conceptually open question. If, however, *N* really was an accurate
analysis of *M* then the question, "I know it is *N* but is it *M*?" would
not be open in this way for a conceptually competent judge any more
than the question, "I know he is a bachelor but is he unmarried?" can
be an open one. Moore himself used the Open Question Argument to
defend a non-naturalist account of goodness but held that rightness
was reducible to goodness. Moore held that it was true by definition
that right actions maximize goodness, though he later came to the
conclusion that this definition of rightness was also vulnerable to an
Open Question Argument. A very similar argument was used by Sidgwick
to establish that certain moral notions are irreducible (see Sidgwick
1907: Book I, Chapter 3) and Moore credits Sidgwick with the idea
(Moore 1903: 17). More recently, some philosophers have argued that
naturalism cannot capture the normativity of moral properties, and
these arguments also seem to be very similar to the Open Question
Argument. The idea seems to be that for any naturalistic reduction one
offers of some seemingly normative notion one can, without betraying
any conceptual incompetence, admit that something has the property
specified by the reductive account but hold that this lacks
normativity--does not provide any reasons for action (see Dancy
1996: 180-183). 




On its face, the Open Question Argument seems to beg the question
against the naturalist just as much as the charge of a naturalistic
fallacy. For if the naturalist holds that a given moral predicate *M* is
equivalent in meaning to some definition *N* couched entirely in
non-moral predicates then she is obviously committed to holding that
the relevant questions are not open and the naturalist might therefore
simply deny the main premise of Moore's argument. However, the Open
Question Argument can be given a non-question-begging interpretation.
The crucial move is to understand the argument as an argument to the
best explanation. On this interpretation, the main premise of the
argument is not that the relevant questions are conceptually open, but
the much more modest premise that they at least seem conceptually open
to competent users of moral terms. The argument then proceeds to claim
that the best explanation of its seeming to competent users of the
terms that these questions are open is that they really are open. That
is, after all, a relatively simple and direct explanation of the
phenomenon and the sort of explanation that we seem to accept by
default when considering conceptual questions in general. This argument
does not beg the question insofar as the opponent of non-naturalism can
grant that the relevant questions do *seem* open without thereby
contradicting their position--the main premise of this argument does
not directly entail non-naturalism.




Once again, however, the scope of the argument is not as great as
Moore supposed. For anti-reductionist forms of naturalism (like Sturgeon's) seem as invulnerable to the argument as Moore's
non-naturalist account. Still, if the argument were to defeat all
reductionist forms of naturalism that would be of substantial interest
and might well be part of larger argument for non-naturalism when
combined with an independent argument against anti-reductionist forms
of naturalism (for further discussion, see Ball 1988, Ball 1991 and
Baldwin 1990: 87-89).




Perhaps unsurprisingly, the Open Question Argument so understood
still faces an impressive battery of objections. Perhaps the meaning of
a predicate is not as transparent to competent users of the predicate
as Moore implicitly assumes. For example, some have argued that
competence with a predicate consists in being disposed (for the most
part) to use the predicate only in ways that are consistent with
certain "platitudes" in which the predicate figures (see, e.g. Jackson
and Pettit 1995). A correct definition of the term might then be
understood as one that best explains those platitudes. On this sort of
account a competent user of moral terms might respect the platitudes
but not recognize the theory that best explicates those platitudes even
if presented with it. An analogy with grammar illustrates the point.
Let us suppose that competent speakers are ones who are disposed (for
the most part) to follow certain grammatical rules but they might not
recognize those rules as valid when presented with them. The question,
"I know the sentence violates this rule but is it ungrammatical?" might
therefore seem to them to be an open one and there need be no mystery
in this. The same might be true in the moral case. The non-naturalist
might respond to this by arguing that if the proposed "platitudes" are
substantial enough to fix the reference of moral terms to some natural
property then the platitudes themselves are vulnerable to an Open
Question Argument. The analogy with grammar might seem to break down at
just this point. For there seems to be much more room for intelligible
moral disagreement amongst competent judges in spite of agreement about
everything else than there is for grammatical disagreement amongst
competent judges in spite of agreement about everything else.




Alternatively, perhaps the best explanation of the apparent
"openness" of the relevant questions to competent users is that the
predicates do not refer to properties at all. For it might be held that
moral predicates do purport to refer to non-natural properties but fail
to refer precisely because those properties would have to be so queer.
This would be to defend a kind of error theory, as defended by John
Mackie (see Mackie 1977 and Joyce 2001). In effect, this would be to
grant that the non-naturalist is right about the semantics (moral
predicates do purport to refer to non-natural properties) but wrong
about the metaphysics (the non-naturalist is wrong to suppose moral
predicates refer to anything).




Even more radically, it might be maintained that moral predicates do
not even purport to refer to properties and that this explains why the
relevant questions seem open. In particular, it has been argued that a
non-cognitivist analysis of moral discourse can explain why the
relevant questions seem open. The question, "I know its pleasant but is
it good?" seems open on this account because one can admit that
something is pleasant (or has whatever natural property you like)
without having decided to approve (or disapprove) of the thing in
question. It is easy enough to see why this would also block the
inference to non-naturalism. For on a non-cognitivist account, as
traditionally understood, moral predicates do not even purport to refer
to properties but rather serve to express speakers' pro- and
con-attitudes. Hence, the non-cognitivist concludes, moral predicates
do not refer to properties at all, much less non-natural ones (see,
e.g., Ayer 1952). In fact, it is fair to say that non-cognitivists
eventually gained at least as much mileage from the Open Question
Argument as non-naturalists.




Finally, more sophisticated forms of reductionist naturalism hold
that while moral predicates do refer to natural properties, they do not
so refer in virtue of any sort of analytic equivalence between moral
predicates and non-moral predicates. The analogy here is with certain
theories of reference borrowed from the discussion of proper names and
natural kinds (see, e.g., Boyd 1988). Some philosophers have held that
identifications of natural kinds like 'water=H2O' are
necessarily true but not analytic. Rather, they are a posteriori
necessary truths that hold in virtue of 'water' bearing the
right causal relation (it has not been easy to say what causal
relations are of the right kind) to H2O. Water and H2O may well be the
same property but a competent user of 'water' need not know
this. Indeed, before the discovery of modern chemistry most users of
'water' did not know this and it is not obvious that the
meaning of the word changed in light of this discovery. If this is a
plausible semantic theory and if a similar theory is true of moral
predicates (a thesis that requires further argument) then the Open
Question Argument is in trouble. For given this semantic theory, just
as a competent user of 'water' and 'H2O' could
without confusion say, "I know it is H2O but is it water?" a competent
user of 'good' and 'pleasant' could say, "I
know it is pleasant but is it good?" without confusion. Whether this
sort of causal theory of reference is plausible in the case of moral
vocabulary is more controversial, but the defender of the Open Question
Argument needs some reason to reject the analogy.


## 3. Intuitionism




How can we come to know anything about non-natural properties? The
question is a reasonable one on any of the myriad ways in which
non-natural properties have been conceived. On many characterizations,
non-natural properties by definition elude scientific investigation
which many take to be the most reliable form of knowledge available to
us. On other characterizations, non-natural properties are causally
inert which makes it hard to see how we could reliably detect them.




At least two kinds of questions are relevant here. First, once we
have a particular property in mind how can we know it is a moral one?
Second, how do we come to know anything about moral properties apart
from knowing they are moral? The first question might seem more
difficult for the naturalist than for some non-naturalists; if goodness
really is a *sui generis* non-natural property then perhaps
being directly acquainted with it is sufficient for recognizing it as
moral. The second question, though, is easier for the naturalist than
the non-naturalist. Since the naturalist holds that moral properties
are either identical to or reducible to some subset of natural
properties there need be no mystery about how we come to have some
knowledge of those properties even if there is some residual mystery as
to how we discover that they are the moral ones. Or, at least, a
commitment to naturalism in meta-ethics introduces no new problems
about how we come to know anything about these properties. For given
naturalism, the moral properties might well be identical to or
reducible to familiar properties like the property of promoting
happiness or the property of being truthful. In general we learn about
such natural properties through observation and scientific inquiry and
the naturalist can "piggy back" on whatever more general
epistemological theory explains our ability to come to know anything
about those properties. We learn, for example, what kinds of upbringing
promote honesty through empirical observation and theorizing.
Non-naturalism can be understood in many different ways, but none seems
to make the task of explaining the possibility of moral knowledge as
straightforward as it seems to be for the naturalist.




The non-naturalist's standard move here is to defend some form of
"intuitionism." In its most straightforward form, intuitionism holds
that we come to know about moral properties through direct observation
of those properties. Just as we can learn that cat is on the mat
through direct observation we can also learn that kicking the cat on
the mat is wrong through direct observation. If we have the appropriate
moral sensibilities and just look carefully enough at a given situation
then we should be able to discern the relevant moral properties as such
quite directly. It is worth noting that this move is in principle
available to naturalists as well as non-naturalists. In some cases this
will be easy; if you watch a bully beat up a defenseless child for fun
then it should be easy enough to see the cruelty and wrongness of his
action. In other cases, discerning the moral facts will be much more
difficult. However, the difficulty of such cases is compatible with
intuitionism. Familiarity with aesthetes makes it clear that perceiving
certain properties can be very subtle and require considerable training
and attention. Plausibly, an intuitionist epistemology fits better
with some versions of non-naturalism than others. If, for example, we
understand non-natural properties as properties we can know only a
priori then the idea that we come to know them through perception seems
problematic. In any event, if intuitionism is defensible then it
provides the non-naturalist with an answer to both of the questions
raised above. Plausibly, if we directly perceive moral properties (at
least partly answering the second question) then we also directly
perceive that they are moral (answering the first question).




Sometimes the intuitionist's perceptual characterization of moral
knowledge is metaphorical. The idea is that moral knowledge is not
literally perceptual in the first instance but is somehow very much
like perceptual knowledge. This approach has its advantages. In trying
to make sense of the idea of moral perception of non-natural
properties, some intuitionists have maintained that our ability to have
veridical experiences of the moral properties is in virtue of our
having a special faculty of mind whose function is to detect such
properties. This raises a number of questions about the origin and
functioning of such a faculty. An account that claims only that moral
knowledge is somehow like perceptual knowledge need not face these
difficulties. Of course, such accounts run the risk of being too vague
to be helpful unless some less metaphorical account of moral knowledge
is forthcoming. Even those who take the idea or perceptual moral
knowledge literally are not thereby committed to belief in such special
faculties. Perhaps moral perception is continuous with other ordinary
forms of perception even if it is literally the perception of a
non-natural property. If non-natural properties are by definition
causally inert then this position seems problematic. On other ways of
understanding non-natural properties, though, whether there is a
problem will depend on further controversial philosophical questions.
For example, if non-natural properties are understood as properties
that would not figure in the best scientific account of reality then
the issue obviously concerns the authority of science to determine the
answers to all ontological questions. Non-naturalists sometimes accuse
their opponents of crude scientism for assuming that science has such
authority and this brings out some deeper methodological differences
between naturalists and non-naturalists (see below, "Methodology").


 One interesting objection to the non-naturalist's deployment of
intuitionism is that this combination of views makes it a
"cosmic coincidence" that our intuitions would reliably
track the moral facts (see Bedke 2009). The force of the worry
derives from the fact that non-natural properties, on some construals,
are causally inert, whereas our intuitions are psychological states
and hence part of the natural world. It is simply not clear how our
intuitions could reliably track such facts, given that they are
causally isolated from them. An obvious contrast is with the way in
which our knowledge of the empirical world plausibly does depend on
reliability secured through suitable causal connections. This is
obviously related to other worries about the way in which the origins
of our moral intuitions does not cohere well with their reliability,
given non-naturalism - e.g. worries which focus more on the Darwinian
influences on human moral judgment (see also Street 2006; for a reply
to such worries, see Vavova forthcoming). Interestingly, some
non-naturalists have tried to give a Darwinian argument for a kind of
non-theological pre-established harmony between our moral intuitions
and the moral facts (see especially Enoch 2011).


 An even more fundamental worry arising out of the causal inertness
of moral properties, given non-naturalism, is how our words and
concepts manage so much as to be about those properties. Certainly on
a causal theory of reference it would be very hard indeed to explain
how our moral words and concepts could refer to such sui generis moral
properties. This worry about what is sometimes called "semantic
access" has only recently started to get the attention it
deserves - see Wedgwood 2009 and Enoch 2011. Matti Eklund develops this worry about reference determination in an especially powerful way (Eklund 2017). He argues that a constraint on a plausible theory of reference determination must ensure that what he calls the "normative role" (roughly, the practical role played by normative predicates in our deliberations about what to do) must be sufficient to determine a unique non-natural referent. Otherwise, it will be possible for there to be other communities to use apparently normative predicates to refer to different non-natural properties. This constraint is very far from trivial to satisfy; Eklund suggests that Wedgwood's theory is unique in trying to meet it. By contrast, a form of non-naturalism like the one defended by Cuneo and Shafer-Landau (Cuneo and Shafer Landau 2014) seems ill-suited to meeting this constraint. On their view, the reference of moral terms and concepts is fixed, in part by more substantive "fixed points" which would seem to go beyond the mere normative role that Eklund has in mind. Although Eklund admits the worry he has is in some ways ineffable, it seems like there ought to be some way in which the properties picked out by our normative predicates are the "right" ones to care about. The reason Eklund's worry is perhaps ineffable is that we presumably must index "right" in "right ones to care about" either to what we mean by "right" or by what some deviant possible community means by "right," but neither seems to capture the intended worry. Eklund notes the obvious analogies with the "Moral Twin Earth" objection to naturalism. 


## 4. Explanatory Impotence




Developing a plausible epistemology (intuitionist or otherwise) is
also essential to meet some of the most pressing objections to
non-naturalism. One such objection begins with the premise that
non-natural properties do not figure in the best explanations of our
experiences and observations. Gilbert Harman famously argues that prima
facie there is a sharp contrast between moral beliefs and scientific
beliefs on this score. The best explanation of scientific beliefs often
seems to entail the truth of those beliefs--Harman gives the example
of a scientist's belief that a proton is in a cloud chamber which seems
to be best explained, in part, by the actual presence of a proton in
the chamber. By contrast, this does not seem to be true of our moral
beliefs. Rather, people's moral beliefs can be explained more elegantly
and plausibly in terms of their upbringing and psychology without
reference to any mysterious non-natural moral properties. This
contrast, combined with the epistemological principle that we should
believe in a property only if it figures in the best explanations of
our experiences entails that non-naturalism should be rejected. Indeed,
Harman's argument would, if sound, also apply to anti-reductionist
forms of naturalism. However, the anti-reductionist naturalist can try
to avoid this line of argument by maintaining that the natural
properties constituting moral properties do figure in the best
explanations of our experiences. Nicholas Sturgeon, for example, argues
that reference to the moral property of being oppressive figures in the
best explanation of the growth of the anti-slavery movement in the
United States between the Revolutionary War and the Civil War (see
Sturgeon 1988: 245; see also Railton 1986), and this is but one of a range of examples
discussed by Sturgeon (for a reply, see Blackburn 1990). However, this
strategy is unavailable to the non-naturalist on many interpretations
of what it is for a property to be a non-natural one. For example, if
it is part of the definition of non-natural properties that they are
not invoked in scientific explanations then this defense is
unavailable. However, on some interpretations of non-naturalism this
move is available. If, for example, non-natural properties are simply
understood as properties that do not figure in similarity relations
then the non-naturalist might argue that often the best explanation of
our moral judgements actually does advert to moral properties.
Intuitionism and its plausibility are likely to be relevant here. The
non-naturalist might argue that people's clear and distinct experiences
of moral properties can be explained only as hallucinations of some
kind in a naturalistic framework, and that this does not do justice to
the clarity and ubiquity of such perceptions.




Alternatively, the non-naturalist might point out that the charge of
explanatory impotence itself must refer to evaluative properties (see
Sayre-McCord 1988b). For the naturalist's objection must be that the
*best* explanation of our experiences does not presuppose the
existence of moral properties of the sort the non-naturalist has in
mind. After all, if any old explanation you like would do then the
non-naturalist could no doubt provide some mediocre explanations of our
experiences that made reference to non-natural moral properties. Once
the naturalist allows that there are non-moral evaluative properties
that are relevant to the assessment of theories there is room for the
non-naturalist to argue that moral evaluative properties need not be
all that different (metaphysically and epistemologically) and hence no
more problematic than the evaluative properties presupposed by the
objection. Moreover, this line of argument suggests that there is
something self-defeating about the naturalist's epistemological
principle. It requires that we believe in properties only if they
figure in the best explanation of our experiences. However, it is not
clear that the property of being a good explanation itself figures in
the best explanation of our experiences. In which case, the
epistemological principle seems to recommend its own rejection. The
problem here is very similar to a problem facing verificationist
theories of meaning which seemed to entail their own meaninglessness.
Presumably the naturalist's best strategy is to argue that the values
she has in mind are purely naturalistic ones that we do have
independent reason to accept because they figure in the best
explanations of our experiences. Whether this strategy is plausible
will depend on the details of the naturalistic theory on offer.





Yet another reply to the objection is to argue that belief in moral
properties (or, more broadly, normative properties) construed in terms
of non-naturalism, is indispensable to our deliberation. The idea
behind this strategy is to argue that there is no reason we should
privilege explanatory indispensability over deliberative
indispensability (see Enoch 2011). One worry about this strategy is
that it is not clear that it helps support belief in specifically
moral properties, but once we embrace non-naturalist realism about
other normative properties there may be no further ontological costs
to accepting the appearances about moral properties too. Like all
transcendental arguments, this defense of non-naturalism is subject to
worries about why the indispensability of some belief to our
deliberation speaks in favor of its truth. Finally, it is not
entirely clear why one must believe in normative properties as
construed by non-naturalism in order to deliberate. A lot of the work
of this argument consists in debunking naturalist and expressivist
conceptions of moral belief as inadequate for our deliberative
purposes. See both Enoch 2011 and Fitzpatrick 2011 for relevant
discussion of this last point. 


## 5. Motivation




It is often held that moral goodness has a kind of "magnetism."
Intuitively, the recognition of moral properties like goodness bears
some sort of intimate connection to motivation--not in the sense of
being sufficiently motivated by such recognition that one actually does the relevant thing
but in the sense of being motivated to some degree to do it. The
general idea that there is some intimate connection between moral
judgement and motivation is usually referred to as "judgement
internalism." (see Darwall 1983: 54). It is not obvious how the
non-naturalist can explain how the recognition of moral properties can
motivate. Mackie famously argues that the defender of objective values
must implausibly maintain that moral properties have a kind of special
causal power to motivate people simply in virtue of their recognition
of them. He argues that the recognition of moral properties must have a
sort of direct influence on the will so that anyone who recognizes them
is thereby motivated. Since a property with this sort of causal power
would be unlike anything else with which we are familiar and fits
poorly into our scientific conception of the world, Mackie argues that
we should not believe in such properties. Mackie's official target is
the thesis that moral properties are objective, but it is clear from
his discussion that non-naturalist interpretations of moral properties
are supposed to be especially vulnerable to his line of argument.
Indeed, Mackie's argument seems to have two stages. First, he in effect
argues that any plausible interpretation of our pre-theoretical beliefs
about morality will presuppose non-naturalism. Second, he argues that
non-naturalism is itself untenable.


 The non-naturalist has a number of possible replies to Mackie's
objection. First, the non-naturalist might simply deny that moral
properties are motivating in Mackie's sense. Mackie's argument seems
to "load up" the concept of a moral property with a lot of
baggage that the non-naturalist need not accept. After all, some
people seem to make perfectly sound moral judgements but remain
unmoved to action by them. Some people care about morality and other
people do not; one need not ascribe any mysterious motivational power
to moral properties to explain why moral properties motivate when they
do (see, e.g., Savavarsdottir 1999). This reply is fair enough so far
as Mackie's initial challenge goes, but it does suggest another
related problem. For now we need some account of why some people care
about morality and other people do not, since it is clear enough that
this depends in some way on the person's environment and
constitution. The non-naturalist may well be able to give such an
account but neither will this be a trivial task.




Second, the non-naturalist might argue that the motivating power of
moral judgements is a trifling semantic truth rather than a deep
metaphysical one. On this account, moral judgements are individuated
not just in terms of their content but in terms of the motivations of
the person making the judgement (see Tresan 2006, though he develops this approach on behalf of naturalism). So on this account someone who
recognizes the property of goodness but is completely unmoved by it
does not thereby have a moral belief. Only when the person has the
appropriate motivations does the belief count as moral. It is unclear,
however, whether this account adequately meets the objection insofar
as it leaves it a mystery why we should individuate moral beliefs in
just this way. Intuitively, it is something about the special nature
of the content of moral judgement that explains why they are
action-guiding, but on this account the content need not play any role
whatsoever in the explanation.




A third reply to Mackie is similar to the second one but tries to
improve on it by offering an explanation of the relationship between
the content of a moral judgement and the appropriate motivation. The
general idea is that moral properties can be recognized only by someone
with certain motivations. It might be held that one cannot recognize
something as cruel, for example, unless one disapproves of it (at least
a little bit) and that cruelty is a non-natural moral property. This
proposal differs from the second one in that it holds that moral
judgements are individuated entirely in terms of their content and not
even partly in terms of their motivational context. It just claims that
judgements with certain contents cannot be made without certain
motivational states (see, e.g., McDowell 1998). Whereas the second
suggestion was semantic ("motivation on the cheap," one might say),
this reply is in part metaphysical and requires substantial work in the
philosophy of mind. In adopting this strategy, the non-naturalist takes
on the burden of explaining why judgements with a distinctively moral
content require appropriate motivations and this is likely to be no
easy task. Cruelty, for example, presumably is a moral concept but
intuitively someone can believe that an action would be cruel and
simply not give a damn. Indeed, intuitively it seems possible for
someone to take the cruelty of an action to be an attractive feature or
a reason to perform the action--schoolyard bullies nicely illustrate
this possibility (a similar point is made in Blackburn 1998: 100) . Nor
does the thesis that cruelty is a non-natural property make the defense
of this view in the philosophy of mind any easier.




Mackie's objection relies on the highly controversial premise that
moral judgements necessarily are motivating and as we have seen the
non-naturalist might reasonably just deny that premise (that was the
first of the three replies discussed above). However, one might instead
appeal to the much more modest premise that if an agent judges that
some possible action of hers is morally required then she will be
motivated to perform that action *unless she is practically
irrational*. Michael Smith refers to this as the "practicality
requirement on moral judgement" (see Smith 1994: 61). This requirement
seems plausible because the recognition that an action is right
plausibly is the recognition that the action is well-supported (perhaps
conclusively supported) by justifying moral reasons for action, and
such a recognition should motivate someone unless the agent is
practically irrational. For present purposes, the point is that even if
Mackie's challenge can be bypassed or met in one of the three ways just
discussed, a further challenge concerning motivation still faces the
non-naturalist. For if the practicality requirement on moral judgement
is correct then the non-naturalist needs to provide some account of why
an agent's recognition that one of the actions available to her has the
non-natural property of rightness is such that her recognition of this
fact rationally requires that she be motivated to perform the
action. In particular, some account of why judging that something is well supported by reasons (understood in non-naturalist terms) is appropriately connected to motivation.




If either of the last two replies to Mackie's objection works then
it can be redeployed against this objection. For if either of those
replies works then the non-naturalist can explain why the relevant
moral judgements necessarily are motivating, which trivially entails
that anyone who makes the relevant moral judgements either is
appropriately motivated or is practically irrational. If, for example,
it is an analytic truth that a judgment does not count as moral unless
it is appropriately motivating then it trivially follows that anyone
who accepts a moral judgment is appropriately motivated or is
practically irrational simply because it follows that anyone who
accepts such a judgment is appropriately motivated. However, these
strategies are problematic in part for just the reason that Mackie's
version of internalism is problematic--both seem to make a certain
kind of practical irrationality impossible by asserting that making a
moral judgment guarantees appropriate motivation. In particular, it
seems possible, though irrational, for an agent to judge that he is
required to do something and yet not be motivated at all to do it. So
perhaps non-naturalists should instead either try to accommodate
Smith's practicality requirement on moral judgement without committing
themselves to a form of judgement internalism as strong as the one
Mackie seemed to have in mind or argue against the practicality
requirement. Of course, if Smith's practicality requirement on moral
judgement is sound then accommodating it is a challenge faced by every
meta-ethical theory, but consideration of how the requirement might be
accommodated suggests that the problem is especially pronounced for the
non-naturalist.




The non-naturalist could simply deny the practicality requirement on
moral judgement (this would be similar to the first reply to Mackie's
objection). This is considerably more controversial than denying the
very strong link between motivation and moral judgement presupposed by
Mackie's objection, but may nonetheless be defensible. The idea would
be that an agent can judge that she is morally required to do something
and not be motivated accordingly without being guilty of any kind of
irrationality. One might hold this on the grounds that the belief that
one is morally required to do something does not commit one to the
belief that there is conclusive reason to do it or on the grounds that
the belief that there is conclusive reason for one to do something
simply does not commit one to being motivated to do it on pain of
irrationality. Unfortunately, a full discussion of the issues
surrounding the truth of the practicality requirement on moral
judgement goes beyond the present scope. For useful discussion, see
Brink 1986, Foot 1972 and Smith 1994.




Alternatively, the non-naturalist might maintain that the
practicality requirement on motivation is a trifling semantic truth.
The idea would be that to be fully rational in part just *means*
doing what one believes to be right. However, this move differs from
the second reply considered above in that it is a clear attempt to
define a normative notion (rationality) in purely naturalistic terms.
This last claim assumes we can give a naturalistic account of
rationality, which is not obviously correct given non-naturalism about
rightness, but neither is it obviously incorrect. In any event, such an
analysis of rationality sits poorly with the non-naturalist's standard
appeal to the Open Question Argument. For if the Open Question Argument
is sound for moral predicates like 'morally required' then
one might have thought that analogous arguments would go through for
'rational' and 'irrational'. After all,
rationality is plausibly a normative notion and on some accounts (see above) it is the idea of
normativity that gives the Open Question Argument its force. This is
one reason the practicality requirement on moral judgement is
especially a problem for non-naturalists, since naturalists are not
committed to accepting the soundness of the Open Question Argument in
the moral case.




Finally, a more recent reply to such objections form motivation is that they misunderstand the role of the relevant non-natural properties in the motivational economy of a virtuous agent. On this view (defended in Chappell 2019), the virtuous agent is not motivated by some simple non-natural property like goodness. That, on this view, would be a sort of fetishism. Rather, the virtuous agent is motivated by the purely natural facts that make the action morally right, e.g. that it spares someone emotional distress. The role of the relevant non-natural property, here the property of being a reason for a given action, is to mark the relevant properties as the ones it is correct to be motivated by. One reply to this argument is suggested by Max Hayward (Hayward 2019). Hayward argues that our commitment to e.g. the value of our partner should not be conditional on the existence and distribution of non-natural properties. Yet non-naturalist moral realism is committed to the view that all value is contingent on the existence of such properties. Transposed to Chappell's emphasis on normative properties as markers of our reasons, Hayward's argument would imply the correctness of treating the relevant facts as reasons should not depend on the sort of obscure metaphysics posited by non-naturalist moral realists.


## 6. Explaining Supervenience




Non-naturalism has trouble explaining the necessary dependence of
the moral facts on the natural facts. So long as our characterization
of natural properties is broad enough to include both all of the mental
properties and all of the properties that would figure in the best
physical theory, it is very plausible to suppose that the moral
supervenes on the natural in the following sense: there can be no moral
difference between two situations or entire possible worlds without
some natural difference but not vice-versa (there can be non-moral
differences without moral differences). On some ways of understanding
the natural properties, of course, it is unclear whether mental
properties are natural ones and this is an important point. Perhaps
mental properties elude scientific investigation but are real
nonetheless. If we characterize the non-natural properties as ones that
elude scientific investigation then mental properties will be
non-natural ones. This is very important since it is not nearly so
plausible that the moral supervenes on a set of facts that does not
include the mental facts--as if the wrongness of an action could
float independently of facts about pain, intentions and beliefs. For
purposes of the present discussion I shall simply assume that the
natural properties include the mental properties.




However, suitably formulated theses concerning the supervenience of
the moral on the natural are plausible enough that some philosophers
have held them to be analytic. Global supervenience theses are perhaps
the most plausible ones, claiming merely that two entire possible
worlds cannot differ *only* in their moral properties without
also differing in some of their natural properties. To deny this thesis
would be to allow that it could have been the case that the world was
*exactly* like the actual world in all of its naturalistic
features but in that world what Hitler did was not wrong. Since all the
natural facts are the same in this possible world it will still be true
that Hitler killed the same people, had the same intentions, etc. Such
bare moral differences seem inconceivable. Very plausibly, the moral
facts are in some way entirely fixed by the natural facts. The problem
for the non-naturalist is that non-naturalism seems unable to explain
this supervenience. For if moral properties and natural properties
really are, in Hume's terms, "distinct existences" then it is hard to
see why it should be impossible for the former to differ with no
difference in the latter and since the natural properties are non-moral
ones (given non-naturalism) this makes supervenience seem problematic.
Non-naturalism's apparent inability to explain such a basic platitude
as global supervenience poses a serious problem (see Mackie 1977,
Blackburn 1984, and Blackburn 1988).




Naturalists of course can explain supervenience much more easily.
For given naturalism, the moral properties just *are* certain
natural properties, and the supervenience of the moral follows
trivially from this (every property supervenes on itself). It is much
less obvious, however, that the naturalist can explain a slightly
different supervenience thesis. For it seems at least as plausible to
suppose that the moral properties supervene on the non-moral ones as it
is to suppose that they supervene on the natural properties. Indeed,
the moral/non-moral supervenience thesis is probably more obviously
correct than moral/natural supervenience theses because of the
obscurity of the natural/non-natural distinction. Once we divide the
natural properties into the moral and the non-moral, it becomes unclear
why the moral properties should supervene on all the *other*
natural properties (the non-moral ones). Perhaps the naturalist's
dialectical advantage is more modest than one would have thought. For
if neither naturalists nor non-naturalists can explain the
supervenience of the moral on the non-moral and if that supervenience
thesis is less controversial than moral/natural supervenience theses
then the fact that the naturalist can explain the latter looks less
impressive.


 Perhaps non-cognitivists (or "quasi-realists," in
Blackburn's favored terminology; see Blackburn 1984) and error
theorists reap the greatest dialectical dividends from reflection on
how we might explain supervenience. The standard view is that the
non-cognitivist's explanatory task differs from the explanatory task
facing both naturalist and non-naturalist forms of cognitivism.
Whereas the naturalist and non-naturalist must explain a metaphysical
relationship between two potentially distinct sets of properties the
non-cognitivist instead needs only to explain the sensibility of a
practice of moralizing governed by a supervenience constraint. Since
one of the main points of moral discourse is to recommend options on
the basis of their natural properties it is easy enough to see why
such a constraint is sensible. To abandon that constraint would be to
abandon the project of moralizing so understood. For if our practice
of moralizing were not to include such a constraint then you could
evaluate options differently even if they were identical in all their
natural properties and this would make it hard to see in what sense
options were being recommended on the basis of their natural
properties. Since for the non-cognitivist there are no moral
properties (from the perspective of serious metaphysics, anyway; but
we can still "speak with the vulgar" as if there were such
properties) we can in the same way derive that our moralizing must not
allow that two items identical in their non-moral properties might
still differ morally. For the point of moralizing is to recommend
options on the basis of their natural properties and all the natural
properties are non-moral according to the non-cognitivist. One worry
about this line of argument is that quasi-realist expressivism, if
successful, allows us to make all of the original and seemingly
metaphysically problematic claims about moral reality in the only
sense in which those claims can be understood. In that case, it
is not entirely obvious why the quasi-realist does not, at the end of
the day, face exactly the same explanatory burden as the
non-naturalist realist (see Street 2011). Perhaps quasi-realists can
avoid this specific worry about self-defeat by holding that moral
properties are, after all, natural properties on their view. The view
can remain expressivist so long as it also maintains that taking a
view about just which natural property is identical to a given moral
property is constituted by adopting suitable non-cognitive
attitudes.




Like the non-cognitivist, the error theorist denies that there any
moral properties, but unlike the non-cognitivist maintains that the
legitimacy of moral discourse presupposes that there are such
properties. This trivially entails that whenever there is a moral
difference there must be some non-moral difference for the simple
reason that there never can be any moral differences between cases
given the error theory. Typically, the error theorist agrees with the
non-naturalist (implicitly, anyway) about the semantics of moral
predicates but holds that moral predicates do not refer precisely
because moral properties to which they purport to refer would have to
be so queer (see Mackie 1977). One aspect of the putative queerness of
moral properties is the idea that they necessarily supervene on the
natural (and non-moral) properties without being reducible to those
properties.




How might non-naturalists respond to the charge that they cannot
explain supervenience? They might argue that the objection must be
unsound because it would prove too much. For the form of the argument
seems to generalize into an argument that no class of properties can
supervene on another class of properties unless the former are
reducible to the latter in some way. It might seem in some of the cases
not involving moral properties that this cannot be correct. The
supervenience of the property of being a chair on all of the properties
of microphysics seems unlikely to be explained in some reductive way
but seems obviously correct nonetheless. Non-naturalist's critics can
either accept this implication of their argument but try to argue that
it is not so implausible or try to block the implication in some way. A
discussion of the former strategy raises very general questions that go
well beyond the scope of the present article. So I shall here focus on
the question of whether the moral case is in some way unique even
though the more promising strategy here might be to argue that in these
other cases some sort of reductive (albeit perhaps non-analytic)
account is available after all.




Arguably the moral case is different from these other cases of
supervenience without reduction because the supervenience of the moral
on the natural (and non-moral) is analytic. Plausibly, someone who
thinks two things could differ morally but be identical in all other
respects does not fully grasp the meanings of moral predicates. This is
not nearly so plausible in other cases in which we seem to have
supervenience without reduction. Cartesian dualists can deny
supervenience and their view does not seem conceptually incoherent
however mistaken it may be. As Blackburn argues, if this sort of error
is a conceptual one then "whole cultures have been prone to denial of
an analytic truth" (Blackburn 1985: 59) which at best seems unlikely.
The idea here seems to be that the only way a realist could explain
supervenience qua analytic truth would be to hold that the moral is
analytically identical to some property that can also be characterized
in purely naturalistic terms. The non-naturalist, of course, is
committed to rejecting any such analyses so if this is the only way to
explain the analyticity of supervenience then non-naturalists cannot
explain it. In which case, the appeal to analyticity might seem to
block the 'proves too much objection'.




However, this would be too quick. Blackburn's appeal to the
analyticity of supervenience in the moral case notwithstanding, the
'proves to much' objection can be reinstated against Blackburn's
original argument that non-naturalists (and moral realists more
generally) cannot explain supervenience. For the non-naturalist might
instead hold that the analyticity of supervenience simply falls out of
the conventions governing our use of moral vocabulary. It is simply an
empirical fact that those we take to be competent users of moral
language do respect supervenience constraints and would think anyone
who did not respect those constraints must be conceptually confused. As
Thomas Baldwin argues, "The realist can maintain that it is a
conceptual truth that there are necessary connections between the
ethical and the non-ethical, even though the particular connections
themselves are not analytically necessary." (Baldwin 1990: 99) In which
case, the appeal to analyticity seems not to help block the objection
that the argument from supervenience proves too much. One might
buttress this defense of non-naturalism by pointing out that it does
seem analytic that moral properties are "resultant" ones in Jonathan
Dancy's sense--the instantiation of a moral property must always be
explained by the instantiation of certain particular non-moral
properties.




Nonetheless, Baldwin is mistaken to suppose that this entirely
disarms the argument from supervenience. Baldwin might well show that
Blackburn cannot escape the charge of proving too much simply by
appealing to the thesis that supervenience in the moral case is a
priori. Showing that Blackburn's move does not explain why the argument
would not prove too much still does not provide a satisfactory defense
of non-naturalism, though. For if the non-naturalist simply appeals to
conventional and linguistic facts then they might well explain why it
is analytic that *if there are any moral properties* then they
must supervene on the natural (and non-moral) ones. The original
objection, though, was a metaphysical one rather than a semantic one.
The problem for the non-naturalist now becomes one of explaining how
the non-natural properties in question could satisfy the relevant
supervenience constraints and hence count as moral in the first place.
The challenge is to provide a metaphysical account of how there could
be properties like the properties to which the non-naturalist maintains
our moral vocabulary purports to refer. Otherwise we are left either
with the error-theoretic conclusion that there are no moral properties
or the non-cognitivist conclusion that moral vocabulary does not even
purport to refer (in the sense of 'refer' in play when one
does serious metaphysics, anyway; again, the non-cognitivist will allow
that we can 'speak with the vulgar' here). So there is
still a problem for the non-naturalist. Nonetheless, Baldwin seems
right in that the appeal to analyticity seems not to have done the work
for which it was invoked by Blackburn. For it again seems as if the
argument from supervenience generalizes to other cases of supervenience
without reduction. Perhaps the non-naturalist's critics should simply
embrace this implication but argue that the prospects for reduction in
these other cases are much brighter than the non-naturalist suggests
they are.




A more promising approach for the non-naturalist would be to offer a
positive explanation of supervenience in explicitly non-naturalist
terms. In his systematic defence of non-naturalist moral realism,
Russ Shafer-Landau takes just this strategy. There he argues that
although each moral property is distinct from any natural property or
properties, still each instantiation of a moral property is fully
constituted (or, as he sometimes puts it, 'realized') by some
concatenation of natural properties (see Shafer-Landau 2003: 76-78).
In effect, the idea is to distinguish types from tokens, and argue
that the constitution of every token moral property by some
concatenation of natural properties is consistent with the
non-identity of that moral property with any natural property or
combination of natural properties. Shafer-Landau suggests that this
strategy is the most plausible one for explaining supervenience
without reduction in the philosophy of mind, and that this should make
us optimistic about the prospects of an analogous strategy in the
moral case.




As I have argued elsewhere, it is not at all clear that the appeal to
token constitution can do the needed work. Moreover, even if this
appeal could somehow explain supervenience, it would have further
unfortunate consequences for the non-naturalist. Since I have
discussed these objections at length elsewhere (Ridge 2007), I shall
be brief here and simply summarize the main worries. First,
Shafer-Landau's constitution thesis by itself does not entail
supervenience. A full explanation of supervenience will require some
auxiliary premises, and Shafer-Landau does not tell us what these
premises are. Fortunately, his appeal to an analogy with the
philosophy of mind helps us fill in the blanks. For the closest
analogue there seems to be David Robb's attempt to explain
supervenience without reduction in the philosophy of mind in terms of
tropes, where tropes just are property instantiations. Trying to
carry out the Robb strategy (which I shall not try to summarize here;
for details, see Robb 1997), the needed premise for Shafer-Landau would
seem to be that if a given natural trope constitutes a moral trope,
then it necessarily constitutes that trope. This, plus
Shafer-Landau's thesis that necessarily, every moral trope is fully
constituted by some set of natural tropes, would indeed entail
supervenience, so this does seem like an interesting way to fill out
the details of his strategy.




Why, though, should we suppose that this necessitation thesis (that if
one trope is fully constituted by another trope, then it necessarily
is) is true? Robb's own thesis was actually about trope identity
rather than trope constitution, and this gives Robb's thesis more
immediate plausibility, as identity does seem to be necessary.
Shafer-Landau, however, wants to appeal to constitution rather than
identity (this is a departure from Robb), and this makes it very
unclear why we should accept the analogous necessitation thesis.




A second possible worry about Shafer-Landau's strategy is that it does
rely on a metaphysics which quantifies over tropes (Shafer-Landau
prefers to speak of 'property instantiations' but this is
really a merely nominal difference). This is itself a controversial
metaphysical commitment. Moreover, Shafer-Landau seems committed to
meta-tropes--tropes of tropes. For he needs this thesis to explain
how a fact (which for Shafer-Landau just is a property instantiation)
can itself have the property of being a reason. While this is of
course a metaphysical commitment that can perhaps be defended, it does
give some dialectical hostages to fortune.




Third, Shafer-Landau's approach seems to have the very odd consequence
that certain forms of first-order monism are ruled out. Shafer-Landau
himself explicitly claims that his theory can be neutral on this
front, and it would be unfortunate if his theory did have such
striking implications for first-order theory. Why do I say that
Shafer-Landau's theory seems to lead very quickly to the rejection of
certain forms of monism? Because on a standard view of tropes, a
property (that is, a type) just is a resembling set of tropes. In
this context, whether a given property is moral or natural will depend
upon whether the relevant sort of resemblance is one which is
especially salient from the point of view of moral theory, on the one
hand, or from the point of view of one of the natural sciences. It
could be relevant from the point of view of both such perspectives,
but this would be for naturalism to be true, which, of course, is
inconsistent with non-naturalism! The main point is that for any
naturalist view which holds that something is good if and only if it
instantiates some particular single natural property (pleasantness,
say), it would follow that the relevant sort of resemblance would be
salient from the perspective of one of the natural sciences. For all
pleasantness tropes do resemble one another in a way which would be
salient from the point of view of psychology (or possibly
biology)--or at least, insofar as pleasantness is a natural
property this is likely to be so. In which case, a standard view of
tropes would entail that the property itself is a natural one. In
which case, we would have a form of reductive naturalism. So for this
strategy to work, it seems that any form of first-order monism which
holds that things are good if and only if they instantiate some single
natural property, must be rejected. Otherwise we end up with a form
of naturalism, rather than non-naturalism. Insofar as the
non-naturalist (quite rightly) aspires to remain neutral on such
first-order questions, this is a theoretical vice of the proposed
explanation.




Obviously there is a lot more that can be said by both parties to this
debate. For example, for useful more recent discussion of the more
general issue of whether there can be necessary connections between
distinct existences, see Wilson 2010. In any event, it is good that
non-naturalists in moral philosophy are not merely relying on the
appeal to companions in guilt, but are also actually offering positive
explanations of supervenience. Shafer-Landau offers an ambitious
explanation of supervenience in non-naturalist terms. Even if his
initial strategy fails for some of the reasons discussed above, it at
least is a step in the right direction, and it might be possible to
refine his strategy in a way to avoid some or all of the worries
raised above. It is early days for this approach to supervenience in
the case of moral philosophy, and it will be interesting to see how
this debate plays out. For further discussion of Shafer-Landau's
strategy here, see also Mabrito 2005, Shafer-Landau 2005, Wedgwood
2009 and McPherson 2012. Useful discussion can also be found in Dreier 2019, Gert 2019, and Moberger 2019. 


## 7. Methodology




The debate over non-naturalism is difficult to resolve in part
because the issues often hinge on fundamentally different
methodological starting points. Advocates of non-naturalism tend to be
less concerned with finding a place for value and obligation in the
world as revealed by science and more interested in taking our common
sense conception of morality as given and seeing what it implicitly
presupposes. Non-naturalism's opponents, by contrast, put a great deal
of weight on explaining our moral practices in a way that fits well
with a properly scientific view of the world and are happy to reject
the presuppositions of common sense if they conflict with that
conception. So non-naturalists tend to be more interested than their
opponents in respecting our pre-theoretical intuitions about morality
and moral judgement. Hence non-naturalists often give substantial
weight to the intuitive force of the Open Question Argument. They also
are less willing to revise common-sense moral beliefs about particular
cases for the sake of aligning those beliefs with some ambitious
naturalistic moral theory. It is no coincidence that so-called moral
particularists, who deny that morality can adequately be captured by
any set of principles linking natural features to moral ones, tend to
favor some form of non-naturalism. Naturalists, by contrast, are more
likely to emphasize the importance of rejecting beliefs that fit poorly
with our best scientific account of reality; if common sense commits us
to properties that do not fit well into that account then so much the
worse for common sense. Given these deep methodological differences,
the only apparent way avoid philosophical stalemate would be to develop
an argument for one of the two positions whose plausibility does not
depend on the controversial methodological assumptions associated with
that position. The best candidate for such an argument considered here
might well be the argument that non-naturalists cannot explain
supervenience. For the supervenience of the moral on the non-moral
seems to fall out of common sense rather than out of our scientific
world-view. Since the methodology associated with non-naturalism itself
puts great weight on common sense, the argument from supervenience
seems like a promising one. At the very least, the argument from
supervenience seems uniquely well situated to undermine non-naturalism
without begging any central methodological questions.