## 1. Varieties of Naturalism: Methodological and Substantive



Different philosophical doctrines travel under the heading of
"naturalism." We can usefully distinguish two broad and
important categories: *methodological* naturalism (or
M-naturalism) and *substantive* naturalism (or
S-naturalism) (Leiter 1998; cf. Railton 1990 and Goldman 1994).
Naturalism in philosophy is most often a *methodological* view
to the effect that philosophical theorizing should be continuous with
empirical inquiry in the sciences. Such a view need not presuppose a
solution to the so-called "demarcation
problem"--i.e., the problem of what demarcates genuine
science from pseudo-science--as long as there remain clear,
paradigmatic cases of successful sciences. Some M-naturalists want
"continuity with" only the *hard* or
*physical* sciences; others seek "continuity with"
any successful science, natural or social. The latter is probably the
dominant strand in philosophy today.



For M-naturalists, "continuity with" the sciences
includes, in the first instance, the Quinean repudiation of a
"first philosophy"--that is, philosophical inquiry
that proceeds entirely *a priori* and without the benefit
of empirical evidence. (Most M-naturalists do not go as far as Quine,
however, in repudiating *any* role for *a priori*
conceptual analysis: see, e.g., Goldman 1986 for a more typical
M-naturalist approach.) Beyond hostility to methods that are
exclusively *a priori*, M-naturalists require continuity with
the sciences in two more precise senses, which we may call
"Results Continuity" and "Methods
Continuity."



Results Continuity requires that the substantive claims of
philosophical theories be supported or justified by the results of the
sciences. For example, epistemologists like Goldman look to the
results of psychology and cognitive science to find out how the human
cognitive apparatus really works; only with that information in hand
can the epistemologist construct norms for how humans *ought*
to form beliefs (Goldman 1978, 1986). Similarly, moral philosophers
like Allan Gibbard and Peter Railton, despite profound substantive
disagreements, both think that a satisfactory account of
morality's nature and function must be supported by the results
of evolutionary biology, our best going theory for how we got to be
the way we are (Gibbard 1990; Railton 1986). A philosophical account
of morality that explains its nature and function in ways that would
be impossible according to evolutionary theory would not, by
naturalistic scruples, be an acceptable philosophical theory.



"Methods Continuity," by contrast, demands only that
philosophical theories emulate the methods of inquiry of
successful sciences. "Methods" should be construed broadly
here to encompass not only, say, the experimental method, but also the
styles of explanation (e.g., identification of causes that determine,
*ceteris paribus*, their effects) employed in the sciences.
Such a view does not presuppose the methodological *unity* of
the various sciences, only that successful sciences have some
methodological *uniqueness*, even if this is not exactly the
same across all the sciences. Historically, Methods Continuity has
constituted the most important type of naturalism in philosophy; it
is found in writers like Spinoza, Hume, and Nietzsche. (However,
unlike the contemporary M-naturalists who draw on the actual
*results* of established sciences, many historical
M-naturalists drawn to Methods Continuity simply try to
*emulate* a scientific way of understanding the world in
developing their philosophical theories.)



M-naturalists, then, construct philosophical theories that are
continuous with the sciences either in virtue of their dependence upon
the actual results of scientific method in different domains or in
virtue of their employment and emulation of distinctively scientific
ways of looking at and explaining things. We may still distinguish
between two different branches of M-naturalism, represented best by
Quine, on the hand, and Goldman, on the other. The former we will call
Replacement Naturalism, the latter Normative Naturalism.
Goldman's paradigm of Normative Naturalism has dominated
research in philosophy (see Kitcher 1992), though it is Quine's
notion of Replacement Naturalism that proves useful for understanding
the American Legal Realists as naturalists in legal philosophy (Leiter
1997). Since both Replacement and Normative Naturalists share the
*methodological* commitment distinctive of naturalism--to
make philosophical theorizing continuous with and dependent upon
scientific theorizing--the difference must be located elsewhere:
not in methodology, but in goal. According to Replacement Naturalists,
the goal of theorizing is description or explanation; to that end,
conceptual and justificatory theories are to be *replaced* by
empirical and descriptive theories. According to Normative
Naturalists, the goal is regulation of practice through the
promulgation of norms or standards. Of course, traditional
epistemology also shares the regulative goal of Normative Naturalism;
what distinguishes the Normative Naturalist is simply the
*methods* employed to realize this objective (cf. Goldman 1986,
pp. 6-9).



Many naturalists go beyond methodological naturalism, however, and
embrace a *substantive* doctrine. S-naturalism in philosophy is
either the (ontological) view that the only things that exist are
*natural* or *physical* things; or the (semantic) view
that a suitable philosophical analysis of any concept must show it to
be amenable to empirical inquiry. In the ontological sense,
S-naturalism is often taken to entail physicalism, the doctrine that
only those properties picked out by the laws of the physical sciences
are real. In the semantic sense, S-naturalism is just the view that
predicates must be analyzable in terms that admit of empirical
inquiry: so, e.g., a semantic S-naturalist might claim that
"morally good" can be analyzed in terms of characteristics
like "maximizing human well-being" that admit of empirical
inquiry by psychology and physiology (assuming that well-being is a
complex psycho-physical state).



Many philosophers are drawn to some type of S-naturalism in virtue of
their M-naturalism: being a philosophical naturalist in the
methodological sense sometimes leads a philosopher to think that the
best philosophical account of some concept or domain will be in terms
that are substantively naturalistic. However, it is important to
notice that a commitment to Methodological Naturalism does
not necessarily entail any substantive conclusions:
methodologically, it is an open question whether the best
philosophical account of morality or mentality or law must be in
substantively naturalistic terms.



The varieties of philosophical naturalism map on to a variety of
naturalistic approaches in legal philosophy. The most radical version
of M-naturalism, Replacement Naturalism, has been articulated and
defended by Leiter (2001b) and arguably by the American
Legal Realists (Llewellyn 1930; Moore and Callahan 1943; Leiter 1997).
The less radical form of M-naturalism, Normative Naturalism, is
exemplified in epistemology by Goldman (1978, 1986), but its
implications for jurisprudence and law have been, to date, only partly
developed (Allen & Leiter 2001; Goldman 1999; Leiter 1998; Talbott
& Goldman 1998). S-naturalism features most prominently in the
writings of the Scandinavian Legal Realists. S-naturalism has also
played a role in motivating Legal Positivism in the Anglo-American
legal-philosophical tradition. More recently, S-naturalism without
normative skepticism has been defended by contemporary moral realists
and natural law theorists like Brink (1988, 1989, 2001) and Moore
(1985, 1992b).


## 2. Replacement Naturalism I: Against Conceptual Analysis



Replacement Naturalism holds that conceptual and justificatory
theories--the traditional fare of philosophy--are to be
*replaced* by empirical and descriptive theories. There are two
kinds of argumentative routes to Replacement Naturalism, both
traceable to Quine: the first arises from doubts about the
analytic-synthetic distinction (Quine 1951); the second from doubts
about foundationalism (Quine 1969). Here we consider the former.



Philosophers have long thought that some truths were
*necessary* while others were *contingent*; in the
twentieth century, under the influence of logical positivism, this was
taken to be the distinction between those statements that were
"true in virtue of meaning" (hence *necessarily*
true) and those that were "true in virtue of fact" (hence
only *contingently* true). The former "analytic"
truths were the proper domain of philosophy; the latter
"synthetic" truths the proper domain of empirical science.
Quine argued that the distinction could not be sustained: all
statements are, in principle, answerable to experience, and,
conversely, all statements can be maintained in the face of experience
as long as we adjust other parts of our picture of the world. So there
is no hard distinction between claims that are "true in virtue
of meaning" and "true in virtue of facts," or
between "necessary" and "contingent" truths;
there is simply the socio-historical fact that, at any given point in
the history of inquiry, there are some statements we are unlikely to
give up in the face of recalcitrant empirical evidence and others that
we are quite willing to give up in light of new empirical
evidence.



Without a domain of analytic truths--truths that are *a
priori* and hold in virtue of meaning--it becomes unclear
what special domain of expertise for philosophical reflection remains.
If all claims are, in principle, revisable in light of empirical
evidence, why not let all questions fall to empirical science?
Philosophy would be out of business, except perhaps as the abstract,
reflective branch of empirical science. This Quinean attack has
consequences for the traditional philosophical business of conceptual
analysis, since on the dominant view from Plato through Carnap
"every analysis of a concept is inextricably bound to a
collection of purported analyticities" (Laurence & Margolis
1999, p. 18). The conclusion Replacement Naturalists draw from the
preceding is that since any claim of conceptual analysis is vulnerable
to the demands of *a posteriori* (i.e., empirical) theory
construction, philosophy must proceed in tandem with empirical
science, not as the arbiter of its claims, but as a reflective attempt
at synoptic clarity about the state of empirical knowledge.



Many resist this conclusion. According to one proponent, a conceptual
analysis proceeds "by appeal to what seems to us most obvious
and central about [the concept in question]...as revealed by our
intuitions about possible cases" (Jackson 1998, p. 31).
"[T]he general coincidence in intuitive responses [to possible
cases] reveals something about the folk theory of [the concept in
question]" (Jackson, 1998, p. 32). But the question that plagues
conceptual analysis, post-Quine, is what kind of *knowledge*
such a procedure actually yields. Why should ordinary intuitions about
the extension of a concept be deemed reliable or informative? Why
think the "folk" are right?



The track record of *a priori* methods like appeal to
intuitions and conceptual analysis is not a promising one (e.g.,
Harman 1994; Hintikka 1999). Kant, for example, took it to be *a
priori* that space necessarily had the structure described by
Euclidean geometry; subsequent physics showed his intuitions to be
mistaken. The lesson naturalists draw from this track record of *a
priori* philosophy is well-expressed by Cummins (1999, pp.
117-18):



> 
> We can give up on intuitions about the nature of space and time and
> ask instead what sort of beasts space and time must be if current
> physical theory is to be true and explanatory. We can give up on
> intuitions about representational content and ask instead what
> representation must be if current cognitive theory is to be true and
> explanatory.
> 



For the Replacement Naturalist, in short, the only sound reason to
prefer a proposed conceptual analysis is not because it seems
intuitively obvious, but because it earns its place by figuring in
successful *a posteriori* theories of the world. Philosophy
*qua* conceptual analysis and intuition-pumping should be
abandoned in favor of empirical science; philosophy is simply the more
abstract and reflective part of empirical science and lays claim to no
distinctive methods or body of knowledge.



Defenders of conceptual analysis, it is true, commonly proclaim the
modesty of their ambitions. Indeed, Frank Jackson specifically
chastises conceptual analysis in its "immodest role,"
namely when "it gives intuitions...too big a place in
determining what the world is like" (1998, pp. 43-44):
"There is nothing sacrosanct about folk theory. It has served us
well but not so well that it would be irrational to make changes to it
in the light of reflection on exactly what it involves, and in the
light of one or another empirical discovery about us and our
world" (Jackson 1998, p. 44). The question is, having conceded
this much, what remains? Conceptual analysis, as Jackson conceives it,
becomes hard to distinguish from banal descriptive sociology of the
Gallup-poll variety. (Jackson even says he advocates, when necessary,
"doing serious opinion polls on people's responses to
various cases" [1998, p. 36].) Such a procedure might deliver
some insight about what some people, at some time, in some place,
think about "mind" or "law" or
"justice," but Replacement Naturalists wonder what
philosophical import any of this data could have, since it is bounded
not simply by time and place, but also by ignorance. Yet, as Ian
Farrell (2006) has argued, such a procedure may serve an important
theoretical purpose, even if its claims are vulnerable to
revision.



How might Replacement Naturalism in legal philosophy, motivated by
these Quinean doubts about conceptual analysis and intuitions,
proceed? Leiter (2001b) suggests one possibility, which invokes the
following example. Joseph Raz (1985) has offered an influential
conceptual argument against Soft Legal Positivism's claim that
there is no constraint on the content of a rule of recognition beyond
the fact that it is a social rule: its existence-conditions are given
by the actual practice of officials in deciding disputes, but what
criteria of legality officials appeal to (i.e., the *content*
of the rule of recognition) is dependent upon whatever the
conventional practice of officials in that society happens to be. Raz
offers an analysis of the concept of authority to show that Soft
Positivism is incompatible, even in principle, with the law's
having the authority it claims to have. According to Raz, it is a
non-normative prerequisite for a claim to authority that it be
possible to identify the authority's directive without reference
to the underlying "dependent" reasons for that directive.
This is a *prerequisite* for authority because what
distinguishes a (practical) authority, on Raz's
"service" conception, is that its directives preempt
consideration of the underlying reasons for what we ought to do, and
thereby make it more likely that we will do what we really ought to
do. Authoritative reasons are claimed to be exclusionary reasons,
excluding from consideration those dependent reasons (including,
importantly, moral reasons) on which the authoritative directive
rests. Soft Positivism, then, undermines the possibility of the rule
of recognition claiming authority, since for Soft Positivism a rule of
recognition can, in principle, employ dependent reasons as criteria of
legal validity. Thus, it would be impossible to identify such a
rule of recognition's directives about legal validity without
recourse to precisely the dependent reasons the rule was supposed to
preempt.



One line of response to Raz has appealed to contrary intuitions about
the concept of authority. Stephen Perry (1987), for example, argues
that authoritative reasons need not be exclusionary in Raz's
sense; it suffices, Perry says, that they simply be
"weightier" than other reasons. Some commentators'
intuitions line up with Raz's (Leiter 2001b), others with Perry
(Waluchow 1994). Now, of course, the Quinean worries about conceptual
analysis hold even in cases where everyone's intuitions about a
concept coincide; but when they do not coincide, the inadequacies of
the philosophical methods at hand seem especially acute. Some
proponents of traditional methods of legal philosophy object that
"the mere fact that there is disagreement about what the
conceptual truths of law are...does not mean that conceptual
analysis of law is fruitless. If that were the case, we should have to
conclude the same about philosophy generally" (Coleman 2001, p.
211 n. 38). Unfortunately, this *reductio* response depends on
a conclusion that the Replacement Naturalist is, in fact, prepared to
embrace--and not because the Replacement Naturalist naively
believes empirical methods "would...put an end to disputes
about the nature of law or anything else" (Coleman 2001, p. 211
n.38). The worry, rather, is that intuitions about concepts enjoy no
privileged epistemic status, while claims in empirical science do.
Even if empirical science does not resolve these disputes, it at least
delineates criteria with epistemic weight for adjudicating them. The
crucial question, then, becomes whether our best empirical science
requires drawing the conceptual lines one way rather than another.



The leading social-scientific accounts of judicial
decision-making--both the informal ones (Pritchett 1949; Powe
2000) and the formal ones (Segal & Spaeth 1993)--have two
striking features in this regard. First, they all aim to account
for the relative causal contribution of "law" and non-law
factors (e.g., political ideologies or "attitudes") to
judicial decisions. Second, they demarcate "law" from
non-law factors in typical Hard Positivist terms, i.e., they generally
treat as "law" only pedigreed norms, like legislative
enactments and prior holdings of courts (as well as, sometimes, the
interpretive methods applied to these kinds of legal sources: see the
treatment of the "legal model" in Segal & Spaeth 1993,
pp. 33-53). If these models were ultimately vindicated
empirically--and not just for American courts--this would
give the Replacement Naturalist reason to abandon any *a
priori*, intuitive confidence we had about the concept of law that
conflicted with Hard Positivism--just as the role of
non-Euclidean geometry in parts of physics has led *everyone*
to repudiate Kant's *a priori* intuitive confidence about
the Euclidean structure of space. If social science really cuts the
causal joints of the legal world in Hard Positivist terms, the
Replacement Naturalist argues, that is a compelling reason to work
with that concept of law as against its competitors.



Proponents of conceptual analysis, by contrast, are skeptical that the
explanatory premises of empirical social scientists give us any reason
to prefer one concept of law to another. Notice, of course, that an
analogous skepticism is available to the diehard Euclidean: after all,
non-Euclidean geometries are famously non-intuitive and hard to grasp.
But even those sympathetic to Kant's view that space is
necessarily Euclidean would have to admit that such a response would
be unmotivated: if non-Euclidean geometry does explanatory work within
successful physical theory, then the right conclusion to draw is that
our intuitions about the structure of space need tutoring to keep pace
with empirical knowledge. So, too, the analogous question for the
natural lawyer or Soft Positivist is: why think your intuitions are
epistemically privileged as opposed to simply untutored by the best
empirical science?



The skeptic, however, might refine the challenge as follows:
"It's not," she might say, "that I insist on
sticking to my intuitions, empirical science be damned. Rather, I do
not see why the empirical science at issue *needs* to take
sides on a dispute about the concept of law." Of course, it is
clear that the empirical social science at issue draws the line
between legal and non-legal norms based on pedigree criteria, but the
question is whether it *needs* to: the natural lawyer could
agree with the social scientists that, e.g., moral and political
considerations determine judicial decisions, but contest the
assumption that these considerations are not themselves legally
binding.



The difficulty, of course, is that the candidate non-law explanatory
factors at issue (e.g., an ideological commitment to the Republican
Party platform) are not plausible candidates for being legal norms, on
any existing theory of the concept of law. Moreover, there are good
reasons why social science treats the explanatory factors at issue as
non-legal. For example, the moral and political attitudes invoked
to explain decisions do not appear explicitly in the text of judicial
opinions or in courts' explicit rationales for
reaching particular outcomes; they are often *hidden* and
*hard to detect*, which makes them quite unlike any of the
paradigm instances of legal norms, such as statutory provisions or
judicial precedents. Finally, the legal/non-legal demarcation in
empirical social science usually reflects more general explanatory
premises about the psycho-social factors that account for behavior,
well beyond the realm of the legal. The motivation for demarcating the
legal/non-legal in essentially Hard Positivist terms is, for most
social scientists, to effect an explanatory unification of legal
phenomena with other political and social behavior.



Yet the very talk of "legal phenomena" may invite a
different kind of objection to the proposed naturalization of
jurisprudential questions. For how is it, one might wonder, that the
social scientist knows these are *legal* phenomena he is
explaining, and not phenomena of some other kind? Does that not
already presuppose an analysis of the concept of law? (Cf. Coleman
2001, pp. 213-214.) It is not obvious, though, why a shared
language and dictionaries (or even an explicit definition of terms,
as, for example, Newton deploys at the start of *Principia
Mathematica*) won't often suffice to get empirical science
off the ground. It is not that empirical science *needs*
conceptual analysis to tell this explanatory story, it's rather
that *after the fact* the philosopher may be able to offer some
greater reflective clarity about the concepts invoked in the
explanatory story. To the extent a conceptual analysis helps, it helps
*after* we discover which way of cutting the causal joints of
the social world works best, according to the naturalist.



All these rejoinders on behalf of naturalism, however, are predicated
on the assumption that we have a robust social-scientific account of
law. Yet it is now plain we do not. (See, e.g., Leiter 2007, pp. 192
ff.) The best social-scientific accounts of adjudication, for
example, boast predictive success that is so feeble (better than
coin-tosses, but not much!) that their explanatory models, with their
implicit concepts of law, earn no epistemic credence. When it comes to
the "concept of law" itself, we may have nothing more than
intuitions, however epistemically feeble, on which to rely. And
perhaps they are not as epistemically feeble as the naturalist
originally thought? Law, after all, is not a natural kind, but a
complicated kind of social artifact, and it seems far more plausible
that social artifacts will depend on folk intuitions and how people
use language: so perhaps traditional conceptual-analytic methodology,
of the kind H.L.A. Hart utilized in *The Concept of
Law*, is the right one after all for its subject-matter (cf.
Langlinais & Leiter 2016)?


## 3. Replacement Naturalism II: American Legal Realism



The *locus classicus* of the second kind of Replacement
Naturalism--the one deriving from an attack on
foundationalism--is Quine's "Epistemology
Naturalized" (1969). The central enterprise of epistemology
on Quine's view is to understand the relation between our
theories of the world and the evidence (sensory input) on which they
are based. Quine's target is one influential construal of this
project: Cartesian foundationalism, particularly in the sophisticated
form given to it in the twentieth century by Rudolf Carnap in *Der
Logische Aufbau der Welt* (1928). The foundationalist wants an
account of the theory-evidence relation that would vindicate the
privileged epistemic status of at least some subset of our theories:
our theories (in particular, our best theories of natural science) are
to be "grounded" in indubitable evidence (i.e., immediate
sense impressions). Quine deems foundationalism a failure: the
semantic part of the program is rendered unrealizable by meaning
holism (theoretical terms get their meanings from their place in
the whole theoretical framework, not in virtue of some point-by-point
contact with sensory input), while the epistemic part of the program
is defeated by the Duhem-Quine thesis about the
underdetermination of theory by evidence (there is always more than
one theory consistent with the evidence, in part because a
theoretical hypothesis can always be preserved in the face of
recalcitrant evidence by abandoning the auxiliary hypotheses that
informed the test of the hypothesis) (see Kim 1988, pp.
385-386).



What becomes, then, of epistemology? Hilary Kornblith has summed up
Quine's view as follows: "Once we see the sterility of the
foundationalist program, we see that the only genuine questions there
are to ask about the relation between theory and evidence and about
the acquisition of belief are psychological questions"
(Kornblith 1994, p. 4). Kornblith aptly dubs this view Quine's
"replacement thesis": "the view that epistemological
questions may be replaced by psychological questions" (Kornblith
1994, p. 3). Here is how Quine puts it:



> 
> The stimulation of his sensory receptors is all the evidence anybody
> has had to go on, ultimately, in arriving at his picture of the world.
> Why not just see how this construction really proceeds? Why not settle
> for psychology? Such a surrender of the epistemological burden to
> psychology is a move that was disallowed in earlier time as circular
> reasoning. If the epistemologist's goal is validation of the
> grounds of empirical science, he defeats his purpose by using
> psychology or other empirical science in the validation. However, such
> scruples against circularity have little point once we have stopped
> dreaming of deducing science from observations. (1969, pp.
> 75-76)
> 



Several pages later, Quine continues that on his proposal,



> 
> Epistemology, or something like it, simply falls into place as a
> chapter of psychology and hence of natural science. It studies a
> natural phenomenon, viz., a physical subject. This human subject is
> accorded a certain experientially controlled input--certain
> patterns of irradiation in assorted frequencies, for
> instance--and in the fullness of time the subject delivers as
> output a description of the three-dimensional external world and its
> history. The relation between the meager input and the torrential
> output is a relation that we are prompted to study for somewhat the
> same reasons that always prompted epistemology; namely, in order to
> see how evidence relates to theory, and in what ways one's
> theory of nature transcends any available evidence. (1969, pp.
> 82-83)
> 



Thus, according to Quine, the central concern of epistemology is
the theory-evidence relationship; if the foundationalist story about
this relationship is a failure, then that leaves only one story worth
telling about this relationship: namely, the story told by "a
purely descriptive, causal-nomological science of human
cognition" (Kim 1988, p. 388). The science of human cognition
*replaces* armchair epistemology: we naturalize epistemology by
turning over its central question--the relationship between
theory and evidence--to the relevant empirical science.



We can now generalize Quine's point as follows (Leiter 1998).
Let us say that a Replacement Naturalist in any branch of philosophy
holds that:



> 
> For any pair of relata that might stand in a *justificatory*
> relation--e.g., evidence and theory, reasons and belief, causal
> history and semantic or intentional content, legal reasons and
> judicial decision--if no normative account of the relation is
> possible, then the only theoretically fruitful account is the
> descriptive/explanatory account given by the relevant science of that
> domain.
> 



This goes beyond Quine in one important respect: for Quine infers
Replacement Naturalism only from the failure of
*foundationalism*--which is simply one possible normative
account of the evidence-theory relationship, but not the only one.
Quine's arguments simply do not show that no other normative
account of the evidence-theory relationship is possible.



Quine has been extensively criticized on precisely this score (e.g.,
Goldman 1986, pp. 2-3; Kim 1988). The key to a successful
defense of Replacement Naturalism lies in an explanation of why
normative theory without foundationalism is *sterile*. One
worry is that without foundationalism, normative theories are
*banal*. Consider: it is now a familiar result of cognitive
psychology that human beings regularly make mistakes in logical
reasoning (cf. Stich 1994). So a mere descriptive theory of
belief-formation, of the sort Quine appears to recommend, would simply
record these mistakes. But shouldn't epistemology tell us that
beliefs *ought* not to be formed illogically? One can hardly
imagine why Quine would disagree: one *ought* not to form
beliefs illogically. But the question is whether this piece of banal
advice adds up to a fruitful research program. The descriptive project
of Replacement Naturalism may record certain irrational cognitive
processes in studying the evidence-theory relationship, but given the
underdetermination of theory by evidence, even when we correct for
logical mistakes, we still won't have an account of which of our
theoretical beliefs are warranted and which are not. The Quinean
intuition is that we'll learn more from the empirical inquiry
than from systematizing our banal normative intuitions about
irrationality. More generally, *unless* we have some
foundational point outside our epistemic practices from which to
assess the epistemic issues, the project of systematizing our mundane
normative intuitions will simply collapse into the descriptive
sociology of knowledge. If we can't stand outside the
epistemological boat, then we can do no more than report what it is we
do. But it is precisely the viability of such an external standpoint
that Quine denies in his embrace of the metaphor of Neurath's
boat. So from within the boat, there is nothing *to do* but
description.



Quine's argument for Replacement Naturalism, recall, moved in
two steps. Step one was *anti-foundationalism*: no unique
theory is justified on the basis of the evidential input. Step two was
*replacement*: since no foundational story can be told about
the relation between input (evidence) and output (theory), we should
replace the normative program with a purely descriptive inquiry, e.g.
the psychological study of what input causes what output. We can find
analogues of both steps in the approach to the theory of adjudication
offered by American Legal Realism.



Theory of adjudication is concerned *not* with the relationship
between "evidence" and "scientific theory,"
but rather with the justificatory relationship between "legal
reasons" (the input, as it were) and judicial decision (the
output): theory of adjudication tries to tell judges how they
*ought* to justify their decisions, i.e., it seeks to
"ground" judicial decision-making in reasons that require
unique outcomes. The American Legal Realists are
"anti-foundationalists" about judicial decisions in the
sense that they deny that the legal reasons justify a unique decision:
the legal reasons underdetermine the decision, at least in most cases
actually litigated. More precisely, the Realists claim that the law is
*rationally* indeterminate in the sense that the class of legal
reasons--i.e., the class of legitimate reasons a judge may offer
for a decision--does not provide a *justification* for a
unique outcome. Just as sensory input does not *justify* a
unique scientific theory, so legal reasons, according to the Realists,
do not *justify* a unique decision.



The Realists also take the second step that Quine takes: replacement.
According to the Realist indeterminacy thesis, legal reasons do not
justify a unique decision, meaning that the foundationalist enterprise
of theory of adjudication is impossible. Why not replace, then, the
"sterile" foundational program of justifying some unique
legal outcome on the basis of the applicable legal reasons with a
descriptive/explanatory account of what input (i.e., what combination
of facts and reasons) produces what output (i.e., what judicial
decision)? As Underhill Moore puts it at the beginning of one of his
articles: "This study lies within the province of jurisprudence.
It also lies within the field of behavioristic psychology. It places
the province within the field" (Moore & Callahan 1943, p.
1). Notice how closely this echoes Quine's idea that,
"Epistemology...simply falls into place as a chapter of
psychology..." (1969, p. 82). Jurisprudence--or, more
precisely, the theory of adjudication--is
"naturalized" because it falls into place, for the
Realist, as a chapter of psychology (or economics or sociology, etc.).
Moreover, it does so for essentially Quinean reasons: because the
foundational account of adjudication is a failure--a consequence
of accepting the Realists' famous claim that the law is
indeterminate.



Of course, this argument for Replacement Naturalism only seems to work
against "formalist" theories of adjudication that are
committed to the rational determinacy of law. But, some object,
"No contemporary analytic jurisprudent is a formalist"
(Coleman 1998, p. 284), and some have even claimed that the
"formalists" the Legal Realists opposed were not committed
to the rational determinacy of law (Paulson 2001, p. 78). Both
objections seem mistaken: Ronald Dworkin, for example, is committed to
the rational determinacy of law in exactly the sense at issue for the
Replacement argument. The targets of the Legal Realist critique were,
equally, committed to the rational determinacy of law (Etchemendy
2021); indeed, it would be impossible to make sense of what the
Realists were doing if that were not so. The Replacement Naturalist
might take the view that there is no reason to call for
"naturalizing" theory of adjudication in the range of
cases where legal reasons *are* satisfactory predictors of
legal outcomes (i.e., precisely those cases where the foundationalist
program can be carried out). One may worry, again, about whether there
is an *interesting* or *fruitful* normative story to be
told (rather than a merely banal descriptive sociology), but it
suffices for the analogy with Quine that there remains some
substantial domain of cases where the foundationalist program cannot
be carried out, so that the case for replacement remains intact.



The real difficulty, of course, pertains not to these historical
points, but to whether or not the project of a normative theory of
adjudication warrants replacement just because rational determinacy
does not obtain. As in the Quinean case, the Replacement Naturalist
must maintain that without rational determinacy, normative theories of
adjudication are banal, mere exercises in descriptive sociology.
Critics of Replacement Naturalism contest this conclusion, though more
by way of affirmation than argument (Coleman 1998, p. 285 n. 44).
However, if the objection under consideration were correct, then a
*normative* theory that specifies what the anti-foundationalist
concedes--namely, that there is more than one (though not simply
any) judicial decision that can be justified on the basis of the class
of legal reasons--must, in some measure, be a theory worth
having. Arguably, such a theory might be adequate to deflect the
challenge to the political *legitimacy* of adjudication based
on the indeterminacy of law, but does it provide the
*normative* guidance to judges we want from a theory? Does a
theory that tells judges they would be justified (on the basis of the
class of legal reasons) in deciding for the plaintiff on theory
*X* *or* the defendant on theory *Y* (but not the
plaintiff or defendant on theory Z!) really provide normative guidance
for judges worth having? The Replacement Naturalist answers in the
negative: better to have a descriptive account of inputs and outputs,
one that would license prediction of judicial behavior, than an
indeterminate normative theory. This response, of course, makes
Replacement Naturalism vulnerable to conflicting intuitions about the
fruitfulness or sterility of different kinds of theorizing.



There are other limits to the Quinean analogy (Leiter 2001a, pp.
284-285; Greenberg 2011 disputes other aspects of the analogy,
while Leiter 2011 replies to some of Greenberg's objections).
First, the American Legal Realists end up presupposing a theory of the
concept of legality in framing their arguments for law's
indeterminacy (Leiter 2001a, pp. 292-293); thus, while they may
believe that the only fruitful account of *adjudication* is
descriptive and empirical, not normative and conceptual, they
themselves need a concept of *law* that is not--at least
on the arguments considered so far--empirical or naturalized. As
one critic of Replacement Naturalism notes: "the naturalist is
committed as a conceptual matter to the existence of a test of
legality.... The naturalist is thus in the same boat with every
other analytic philosopher of law" (Coleman 2001, p. 214). The
analogy with naturalized epistemology, in other words, must be
localized to the theory of adjudication, and not the whole of
jurisprudence. Of course, it remains possible for the Replacement
Naturalist to argue for the requisite concept of legality on precisely
the empirical grounds noted in the previous section
("Replacement Naturalism I: Against Conceptual Analysis").
But as it stands, the analogy to Quine's attack on
foundationalist epistemology warrants no radical abandonment of
traditional conceptual analysis across the board.



A second difference from Quine is also important. The crux of the
Legal Realist position (at least for the majority of Realists) is that
non-legal reasons (e.g., judgments of fairness, or consideration of
commercial norms) *explain* the decisions. They, of course,
explain the decisions by *justifying* them, though not
necessarily by justifying a unique outcome (i.e., the non-legal
reasons might themselves rationalize other decisions as well). Now
clearly the descriptive story about the non-legal reasons is not going
to be part of a non-mentalistic naturalization of the theory of
adjudication: a causal explanation of decisions in terms of reasons
(even non-legal reasons) does require taking the normative force of
the reasons *qua reasons* seriously. The behaviorism of Quine
or Underhill Moore is not in the offing here, but surely this is to be
preferred: behaviorism failed as a foundation for empirical social
science, while social-scientific theories employing mentalistic
categories have flourished. Moreover, if the non-legal reasons are
themselves indeterminate--i.e., if they do not justify a
*unique* outcome--then any causal explanation of the
decision will have to go beyond reasons to identify the psycho-social
facts (e.g., about personality, class, gender, socialization, etc.)
that cause the decision. Such a "naturalization" of the
theory of adjudication might be insufficiently austere in its ontology
for Quinean scruples, but it is still a recognizable attempt to
subsume what judges do within a (social) scientific framework.


## 4. Normative Naturalism



Like the traditional epistemologist, the Normative Naturalist embraces
as his goal the promulgation of norms by which to regulate our
epistemic practices--to govern how we should acquire and weigh
evidence, and ultimately form beliefs. Unlike the non-naturalist,
however, the Normative Naturalist does not think epistemic norms can
be adequately formulated from the armchair: normative theorizing must
be continuous with scientific theorizing. But if this is not just to
collapse into Replacement Naturalism, then what does the M-naturalist
credo amount to in the normative case? Consider Goldman's
proposal: "Epistemics assumes that cognitive operations should
be assessed instrumentally: given a choice of cognitive procedures,
those which would produce the best set of *consequences* should
be selected" (1978, p. 520). The Normative Naturalist maintains
that the reason the philosopher can't do armchair epistemology
is because it is an *a posteriori*, empirical matter what norms
*in fact* serve our epistemic or cognitive goals (e.g., forming
true beliefs). Goldman emphasizes a particularly important instance of
this general point:



> 
> [A]dvice in matters intellectual, as in other matters, should take
> account of the agent's capacities. There is no point in
> recommending procedures that cognizers cannot follow or recommending
> results that cognizers cannot attain. As in the ethical sphere,
> "ought" implies "can." Traditional
> epistemology has often ignored this precept. Epistemological rules
> often seem to have been addressed to "ideal" cognizers,
> not human beings with limited information-processing resources.
> Epistemics [as a type of Normative Naturalism] wishes to take its
> regulative role seriously. It does not want to give merely idle
> advice, which humans are incapable of following. This means it must
> take account of the powers and limits of the human cognitive system,
> and this requires attention to descriptive psychology. (1978, p. 510)
> 



So the Normative Naturalist thinks that normative epistemology must be
continuous with natural and social science in (at least) two senses:
(i) we need to know what epistemic norms in fact lead to our forming
true beliefs; and (ii) as a special case of (i), we need to identify
epistemic norms actually usable by creatures like us. This rules out
certain (non-naturalistic) epistemic norms which require of cognizers
belief-formation practices beyond their ken (Goldman 1978, pp.
512-513). The Normative Naturalist, in short, emphasizes the
*instrumental* character of normative theorizing in
epistemology, and then argues that the only way to assess instrumental
claims is empirically--to see what means *really* brings
about what ends. And that task can never be pursued *a priori*,
from the armchair.



Of course, it bears noting that the Normative Naturalist does not
dispense *entirely* with conceptual analysis--to the
contrary. It is precisely, for example, Goldman's proffered
conceptual analyses of "knowledge" and
"justification" that require him to turn to empirical
psychology to fill in the actual content of epistemic norms. Unlike
the Quinean program, naturalization enters for the Normativist only,
as it were, in *applied* epistemology. What many philosophers
might think of as "pure" epistemology--giving an
account of knowledge--continues to be an *a priori*
enterprise, even though it is an enterprise that invokes notions (like
"reliability" and "causation") that require
*a posteriori* investigation to apply.



The Normative Naturalist in jurisprudence, too, views theoretical
questions *instrumentally*. The philosophical foundation of
evidence law has, to date, received the most attention from this
perspective (Allen & Leiter 2001; Broughton & Leiter 2021). We
want to ask, as Goldman puts it, "Which [social] practices have
a comparatively favorable impact on knowledge as contrasted with error
and ignorance?" (1999, p. 5). Normative naturalism is, in this
respect, *veritistic* (to borrow Goldman's term): it is
concerned with the production of knowledge, meaning (in part)
*true* belief (Goldman 1999, pp. 79-100). So the
Normative Naturalist embraces as his goal the promulgation of norms by
which to regulate our epistemic practices so that they yield
knowledge. In the case of *individual* epistemology, this means
the norms governing how individuals should acquire and weigh evidence
as well as, ultimately, form beliefs; in the case of *social*
epistemology, this means the norms governing the social mechanisms and
practices that inculcate belief. The legal rules of evidence, in turn,
are a prime case of the latter: for these rules structure the
epistemic process by which trial jurors arrive at beliefs about
disputed matters of fact. As such, the rules of evidence are a natural
candidate for investigation by Normative Naturalists. We may ask of
any particular rule: does it increase the likelihood that jurors will
reach *true* beliefs about disputed matters of fact? (Of
course, it does not make sense to ask that of *every* rule,
since some rules of evidence--for example, Federal Rules of
Evidence (FRE) 407-411--are not meant to facilitate the
discovery of truth, but to carry out various policy objectives like
reducing accidents and avoiding litigation.) That means, of course,
asking an essentially *empirical* question: does a given rule
of evidentiary inclusion or exclusion *in fact* increase the
likelihood that fact finders, *given what they are actually
like,* will achieve knowledge about disputed matters of fact
(i.e., does it maximize veritistic value)? Of course, many rules
that on their face invite one kind of veritistic analysis require a
very different kind in practice. So, for example, FRE 404, *on its
face*, excludes character evidence in most contexts, though, in
fact, the exception in 404(b) largely swallows the rule. Thus, while
it might seem that we should ask whether *excluding* character
evidence maximizes veritistic value, the real question is whether
*admitting* it does. The same may be said for the hearsay rule.
Although on its face, the hearsay doctrine is a rule of exclusion, in
reality it is a rule of admission: what the advocate must really know
is how to get the proffered hearsay admitted under one of the
multitude of exceptions to the nominal rule of exclusion (FRE 802).
Thus, the pertinent veritistic question concerns the veritistic
credentials of the grounds on which hearsay is admitted, rather than
the veritistic reasons for excluding it in most cases. (Such
questions, in fact, are already a staple of much evidence
scholarship.)



In theory of adjudication, by contrast, the Normative Naturalist wants
to identify norms for adjudication that will help judges realize
adjudicative goals. Such norms must, once again, satisfy two
naturalistic constraints: first, they must, as a matter of empirical
fact, be effective means to goals ("the Instrumental
Constraint"); second, they must be constrained by relevant
empirical facts about the nature and limitations of judges ("the
Ought-Implies-Can Constraint") (Leiter 1998).



Dworkin's theory of adjudication (Dworkin 1986) makes a popular
target for the Normative Naturalist. Dworkin's theory says, very
roughly, that a judge should decide a case in such a way that it
coheres with the principle that *explains* some significant
portion of the prior institutional history *and* provides the
best *justification* for that history as a matter of political
morality. Can a Normative Naturalist be a Dworkinian?



(1) **Instrumental Constraint**: The naturalist assesses
normative advice relative to its actual effectiveness for realizing
relevant goals. What, then, is the relevant goal in
*adjudication*? One candidate is surely this: we want to give
judges normative advice that will lead them to reach fair or just
outcomes. Thus, the naturalist's question becomes: which piece
of normative advice is most effective in *really* helping
actual judges realize justice and fairness? It is, at least, an open
question whether Dworkin's methodology will be effective in
leading judges to do fair things. The fact that his normative theory
has had almost no impact whatsoever on American judicial practice over
the last forty years is at least defeasible evidence that it does not
appear to be an *effective* methodology (let alone one
effective for realizing justice!) (Leiter 1998, p. 102). This latter
point is related to the naturalist's second, and more important,
objection.



(2) **Ought-Implies-Can-Constraint:** One thing judges
cannot do is what Dworkin's Judge Hercules does. This is a
familiar complaint about Dworkin's theory, but naturalized
jurisprudence gives it a principled foundation. The naturalistic
jurisprudent eschews all normative guidance unusable by real judges;
like his naturalized counterpart in epistemology, he does "not
want to give merely idle advice, which humans [including judges] are
incapable of following" (Goldman 1978, p. 510). Dworkin may give
judges an "aspirational model" (to borrow Jules
Coleman's apt phrase), and the naturalistic jurisprudent need
not dispute that; but Descartes gave us an aspirational model in
epistemology as well, and that does not make his program any more
adequate or relevant by the naturalist's lights. (It
*would* be attractive if we could take certain "clear and
distinct" ideas, and build up all of knowledge from them.) The
naturalist wants normative advice effective for *creatures like
us*; demanding of judges Herculean philosophical ingenuity
violates this constraint. Aspiration, the naturalist concludes, is not
a fit aim of normative advice, which must, first and foremost, offer
*effective* means to ends.


## 5. Substantive Naturalism



Substantive naturalism begins with the idea that there exist only
*natural* things, things of the kind natural science describes.
(Physicalism, a more severe form of S-naturalism, holds that there are
only *physical* things.) This ontological S-naturalism may,
though need not, go with semantic S-naturalism, according to which a
suitable philosophical analysis of any concept must show it to be
amenable to empirical inquiry.



S-naturalism has played a significant role in at least three
legal-philosophical traditions: (1) the Scandinavian Legal Realists
(like Alf Ross and Karl Olivecrona), whose austere ontological
naturalism, conjoined with moral anti-realism, shaped their
distinctive take on legal concepts; (2) Legal Positivists, for whom
S-naturalism can be, and sometimes has been, a significant motivation,
and (3) contemporary defenders of a kind of natural law theory (like
David Brink, Michael Moore, and Nicos Stavropoulos), who invoke the
Causal Theory of Reference associated with Kripke and Putnam to offer
an interpretation of some legal predicates in substantively
naturalistic terms.


### 5.1 Scandinavian Legal Realism



Scandinavian Legal Realism stands out from other major traditions in
legal philosophy for expressly placing naturalism--and
S-naturalism in particular--at center stage. Perhaps the most
striking example of this comes in the preface to the Second Edition of
Karl Olivecrona's *Law as Fact*, where Olivecrona states
that the aim of his book is "to fit the complex phenomena
covered by the word law into the spatio-temporal world" (1971,
p. vii). But S-naturalism is equally prominent in Alf Ross'
*On Law and Justice* (1959, p. 67; see also Spaak 2009, pp.
40-42), probably the most internationally famous contribution to
the Scandinavian Realist tradition. Given the centrality of
S-naturalism to Scandinavian Realism, it is unsurprising that a
variety of familiar naturalism-motivated philosophical gambits feature
prominently in the major Scandinavian Realist texts. These include
efforts at naturalistic reduction of legal concepts, as well as
non-cognitivist and error-theoretic accounts of important aspects of
legal discourse. (Some particular examples are discussed below.)



The S-naturalism of the Scandinavian Realists is today viewed more as
an intellectual-historical museum piece than as a live contender in
jurisprudential debate. That Scandinavian Realism should have fallen
out of favor is not altogether surprising, given the strong influence
of logical positivism and the similar Uppsala school of philosophy on
the philosophical outlook and approach of the major Scandinavian
Realists (Bjarup 1999, p. 774; see also Sandin 1962, p.
496). Although many would still sympathize broadly with the
Scandinavian Realists' naturalism, anti-metaphysical
inclinations, and moral anti-realism, their specific versions of these
doctrines have not, as a general matter, aged well. Be that as it may,
the poor long-term reception of the Scandinavians may be owed, in
large part, to a rather more accidental cause: the influence of Hart
(1959). In an influential review of Ross' *On Law and
Justice*--simply (and somewhat misleadingly) titled
"Scandinavian Realism"--Hart famously attacked a
central pillar of Ross' legal philosophy, namely his austerely
naturalistic analysis of the concept of legal validity. Ross (1962)
responded in his own review of Hart's *The Concept of
Law*, arguing that Hart had misunderstood him and that their
views, properly understood, were not so far apart.



In order to understand what it was that Ross proposed and that Hart
found so objectionable, it is best to begin with the opening pages of
*On Law and Justice*. There, Ross draws a distinction between
two kinds of linguistic meaning: expressive and representative.
According to Ross, all linguistic utterances, oral or written, have
expressive meaning (i.e., express something); but only some have
representative meaning, i.e., represent states of affairs in the
world. Here Ross contrasts an utterance like "my father is
dead," which has expressive and representative meaning, with
utterances like "ouch!" and "shut the door,"
which have expressive meaning only. Ross calls utterances with
representative meaning "assertions." Utterances without
representative meaning he calls either "exclamations" or
"directives"--the former if they are not intended to
exert influence on others (as in the case of a reflexive cry of
"ouch!"), the latter if they are intended to exert
influence (as in the case of "shut the door") (1959, pp.
6-8).



Ross holds that legal rules, such as statutory provisions, are
directives. He explains that such rules are not meant to represent
states of affairs, but to influence behavior. Simply put, if a legal
rule is laid down stating that certain behavior "shall be
punished" or "gives rise to liability," this is not
done to describe what courts would do anyway, but to *direct*
the behavior of courts (and, indirectly at least, the behavior of
private individuals) (1959, pp. 8-9).



What, then, of the legal utterances "occurring in a textbook of
law"? Are these assertions or directives? At a surface level,
Ross tells us, the language in such books will often be similar or
even identical to the language in an actual statute: a doctrinal
writer might, for example, say that certain behavior "gives rise
to liability" or "shall be punished." But we should
not be misled by this surface similarity, Ross says: "the
propositions in a textbook, at any rate to a certain extent, intend to
describe, not to prescribe" (1959, p. 9). To that extent,
therefore, they must be assertions, not directives--specifically,
Ross claims, assertions about what is *valid law*.



And what does it mean to say that something is valid law? In effect,
Ross tells us, it is to predict the behavior and thinking of courts.
Details aside, to say that "*X* is valid law"
is in effect to say that (1) judges will act in accordance
with *X*, and (2) in so acting, they will feel themselves bound
to do so. Hence, claims about what is valid law are claims about
purely natural-factual states of affairs: facts about the behavior and
psychology of judges (1959, pp. 42, 73-74, 75).



The Hart-Ross dialogue revolved around the merits of this
analysis; Hart, for his part, found it altogether inadequate. Most
crucially and memorably, Hart argued that "even if in the mouth
of the ordinary citizen or lawyer 'this is a valid rule of
English law' is a prediction of what [English] judge[s] will do,
say and/or feel, this cannot be its meaning in the mouth of a judge
who is not engaged in predicting his own or others' behaviour or
feelings." Instead, it is an "act of recognition" of
"the rule in question as one satisfying certain accepted general
criteria for admission as a rule of the system and so as a legal
standard of behaviour" (1959, p. 165). At root, Hart argued,
Ross' analysis of the concept of legal validity fails because
"the normal central use of 'legally valid' is in an
internal normative statement of a special kind" (1959, p.
167).



Later, in his review of Hart's *The Concept of Law*, Ross
claimed that Hart had misunderstood him. In his analysis of
"valid law," Ross replied, he had been concerned
specifically with "legal concepts as they function in the
doctrinal study of law, what we on the Continent are accustomed to
call the science of law," and if this were adequately
understood, it would be evident that much of the apparent disagreement
between him and Hart was illusory (1962, p. 1190). In effect, Ross
said, he had been analyzing legal statements of a kind Hart would have
classified as "external." Ross chalked up the confusion at
least in part to the translation of the Danish phrase
"*gaeldende ret*" as "valid law,"
acknowledging that the results sounded "odd in English
usage," and suggesting in passing that "existing
law" or "law in force" might have better captured
what he had in mind. (For further discussion of the translation
question, see Eng 2011.)



A number of subsequent authors who have revisited the Hart-Ross
debate have expressed broad sympathy for Ross' claims to have
been misunderstood. (See Pattaro 2009, pp. 545-546; Eng 2011;
Holtermann 2014, p. 166 n. 4.) Nonetheless, as a matter of
intellectual history, Hart's critique had its effect. There has,
however, been a recent uptick in interest in Scandinavian Legal
Realism, perhaps owing in part to a broader renewal of interest in
naturalism in legal philosophy. This has not been limited to strictly
historical or exegetical work, but has included efforts to mine the
Scandinavian Realists' writings for philosophical strategies or
insights that might help advance contemporary legal philosophy, or to
offer fruitful rational reconstructions of their ideas. (See, e.g.,
Holtermann 2014; Spaak 2014, Ch. 10.)



One topic of some contemporary interest to which the Scandinavian
Realists may be relevant is the possibility of understanding legal
language in expressivist and/or non-cognitivist terms. Largely owing
to Kevin Toh's work on the subject, there has been some recent
interest in legal (or "meta-legal") expressivism, that is,
treatments of legal statements as expressions of distinctive (perhaps
conative) mental states. (See Toh 2005; Toh 2011; Etchemendy 2016.)
Contemporary legal expressivists might look to the Scandinavian
Realists as intellectual forebears of a sort, given the prominence of
non-cognitivist ideas in their theories of legal language.



As is widely recognized, the Scandinavian Realists were ethical
non-cognitivists. (Bjarup 1999, p. 775; Ross 1959, p. 313; Spaak 2009,
pp. 42-44, 52-55, 64.) In principle, this would not
require adopting expressivist or non-cognitivist accounts of legal
statements, but as it happens Ross and Olivecrona did understand
substantial parts of legal discourse on this model. To be sure, Ross
analyzed statements about "valid law" as assertions of
naturalistic fact, and thus cognitive. But, as discussed earlier, Ross
thought some legal utterances were non-cognitive directives. This most
obviously included legal rules themselves, as in the provisions of a
statute. But Ross also thought jurists' doctrinal writings were
typically a blend of cognitive assertions of valid law and
non-cognitive directives, the latter being in effect advice calculated
to influence the behavior of the judiciary (1959, pp. 46-49). In
advancing this idea, Ross was not merely making the banal point that
doctrinal writing is frequently laced with transparently normative
claims about how courts should decide cases. His point was subtler
than this; telegraphically stated, Ross' observation was that
doctrinal writers sometimes do (and sometimes intend to) influence
judges by making statements that could, on their face, equally be
interpreted as straightforward predictive/descriptive claims. It turns
out, therefore, that Ross had a rather nuanced understanding of the
mix of cognitive (or representational/descriptive) and non-cognitive
(or directive/prescriptive) elements in legal discourse.



If anything, non-cognitivist ideas play an even more striking role in
Olivecrona's mature legal philosophy, notably as set out in the
Second Edition of *Law as Fact*. Unsatisfied with efforts to
reduce talk of legal rights to claims about naturalistic states of
affairs, Olivecrona ultimately concludes that the word
"right," as commonly used, does not signify anything and
lacks semantic reference (1971, pp. 183-184). In the first
instance, he argues, statements about legal rights serve a directive
function, though they can also indirectly serve to communicate
information about actual (naturalistic) facts. Ultimately, Olivecrona
extends this analysis to legal language in general, concluding:
"Legal language is not a descriptive language. It is a
directive, influential language serving as an instrument of social
control" (1971, p. 253). Lest there be doubts about how far
Olivecrona took this idea, he went on to observe that on his account,
"Citizen, government, parliament, law, right, duty, marriage,
elections, taxes, corporations, and princess all belong to th[e]
category" of "words which...lack semantic
reference" (1971, p. 255). Thus, Olivecrona found no place for
many of the "things" legal language is ostensibly
"about" in the world of facts that he countenanced as an
S-naturalist. As so often happens with philosophers who embrace
non-cognitivism about some domain of thought and talk, however,
Olivecrona was equally insistent that legal *language and
ideas* do find a place in reality. He accordingly devoted
considerable attention to describing the function of legal language in
society--concluding, ultimately, that "legal language plays
a vital role" as "an instrument of social control,"
"for keeping the peace, as well as for sending men to death on
the battlefield" (1971, p. 254). Insofar as there is some
contemporary interest in expressivist and/or non-cognitivist accounts
of legal thought and talk, therefore, Scandinavian Realism may offer
interesting intellectual-historical reference points (and possibly
substantive inspiration) for the further development of such
ideas.


### 5.2 Legal Positivism



At least in contemporary Anglo-American legal philosophy, "Legal
Positivism" is generally used as a shorthand for a claim roughly
along the following lines: "the existence and content of law
depends on social facts and not on its merits" (Green 2009).
What is the relationship between naturalism and Legal Positivism in
the above-specified sense? The situation is somewhat complex because
some but not all Legal Positivists are naturalists, and few have gone
so far as the Scandinavian Realists in wearing their naturalism on
their sleeves. In brief, however, naturalism can and sometimes
has--but *need not*--play a role in motivating Legal
Positivism.



How is it that naturalism *can* play a role in motivating Legal
Positivism? As has often been remarked, the core Positivist claim
about the relationship between law and social facts amounts in effect
to a claim that law is reducible to social facts, which--given
that "social facts" here is, tacitly if not expressly,
limited to psychological and sociological facts--further amounts
to the claim that law is reducible to naturalistic facts. It should be
clear enough why this would be appealing to people with S-naturalist
commitments, for it would, so to speak, mean that we can
"place" law in the realm of naturalistic facts and
entities. (By analogy, consider why S-naturalists would be drawn to
the idea that the existence and contents of human *minds*
depends solely on facts about human *brains*.) Unsurprisingly,
therefore, the affinities between Legal Positivism and S-naturalism
have not gone unnoticed. (See Kar 2006, p. 931; Leiter 2018, pp.
19-20.)



It is, however, somewhat harder to discern the actual extent to which
S-naturalism has been a motivation for major philosophers in the Legal
Positivist tradition. There is at least a good case to be made that
Hart was sufficiently attracted to S-naturalism to consider it an
advantage of Legal Positivism that it placed law in the world of
earthly facts. (See Hart 1961, pp. 11-12, 83-84, 186; Raz
1998, pp. 4-5; Toh 2005, pp. 83-85.) Even so, Legal
Positivism need not be, and is not always, motivated by S-naturalism,
or for that matter any kind of naturalism, and not all Legal
Positivists are naturalists in any interesting sense. For example, Raz
does not appear to be a naturalist of any sort. (See Raz 1988, p. 6.)
The broader point, of course, is that one need not be a naturalist to
think that some *particular* phenomenon (e.g., law) depends
solely on naturalistic facts.



Thus, it pays not to overstate, or to make overgeneralizations about,
the relationship between naturalism and Legal Positivism. We can,
however, confidently say that Legal Positivism sits well with a
background commitment to S-naturalism. This point is of no small
importance given the continuing influence of S-naturalism (or at least
temperamental affinities to S-naturalism) in the general background
framework of post-Enlightenment culture and thought. (See Leiter 2018,
p. 19.)


### 5.3 S-Naturalism, Law, and the Causal Theory of Reference



Just as semantic doctrines more-or-less related to logical positivism
were central to the S-naturalism of Scandinavian Realism, the more
recent S-naturalism of writers like David Brink, Michael Moore, and
Nicos Stavropoulos is indebted to the revolution in semantics
initiated by Hilary Putnam and Saul Kripke known as the
"new" or "causal" theory of reference. These
latter doctrines are not--yet in any case--museum pieces, so
the derived jurisprudential theses are very much live items of debate.
Stavropoulos explains the core semantic ideas on which jurisprudential
writers draw as follows:



> 
> Both Kripke and Putnam attack what they call the traditional theory of
> reference. That theory holds that an expression refers to whatever
> fits the description with which speakers associate the expression. The
> relevant description...captures necessary properties of the
> referent which are knowable *a priori*, as in the case of
> knowing that a bachelor is an unmarried man. This cannot be true,
> Kripke and Putnam argue, since expressions refer to the same object in
> the lips of speakers who can only associate the expression with vague
> or mistaken descriptions. Indeed, not only individual speakers but the
> community as a whole can be in error about the true properties of the
> relevant object. ... The important suggestion being made by
> Kripke and Putnam is that reference is *object-dependent*.
> *Which* object 'Aristotle' or 'water'
> refers to is not determined by the associated description, but turns
> instead on a matter of fact, namely which object the name-using or
> term-using practice is directed at. (1996, p. 8)
> 



Thus, if on the old view the "meaning" of an expression
(the descriptions speakers associated with it) fixed the reference of
the expression, on the new theory, the referent fixes the meaning.
"Water" picks out whatever stuff we happened to baptize
with the name "water" at the beginning of the
"term-using practice." As it happens, that stuff has a
distinctive micro-constitution: it is H20. Thus,
"water" refers to stuff that is H20, and that
is what the term means: the stuff that is H20.



Writers like Brink, Moore, and Stavropoulos propose that when the
meaning of expressions in legal rules--and, in particular, the
meaning of the moral concepts (like "equality") that
figure in some legal rules--is understood in the same way, then
it follows that all rules have *determinate* applications:
either the facts do or do not fall within the extension of the meaning
of the key terms in the rule. The meaning of the rule determines its
application, but the meaning is fixed by the *real* referents
of the terms in the legal rule. Of course, for this to be a version of
S-naturalism, the claim must be that the real referents are themselves
things cognizable within a naturalistic framework. So, e.g., it
would have to be the case that the legal and moral features of
situations picked out by our legal concepts (and the moral concepts
embedded in them) must be identical with (or supervenient upon)
natural facts: just as there are necessary, *a posteriori*
statements of property identity about water, so too there are such
statements about legal and moral facts. For example, perhaps the
property of being "morally right" is just identical with
the property of "maximizing human well-being," where the
latter may be understood in purely psychological and physiological
terms. In that case, whether an action *X* is morally right is
simply a scientific question about whether action *X* will in
fact maximize the relevant kinds of psychological and physiological
states in the world. (Most naturalistic moral realisms are based on
versions of utilitarianism, precisely because it is easy to see what
the naturalistic base of moral properties would be in a utilitarian
schema. One peculiar feature of the moral realism of Moore (1992b) is
that it is conjoined with a deontological moral theory, yet within a
purportedly naturalistic moral realist framework.) The crucial claim,
plainly, is that moral facts are to be identified with (or treated as
supervenient upon) certain kinds of natural facts. Of course, many
philosophers are skeptical that this claim can be made out.



Problems arise at several different levels with this more recent
S-naturalism, though all are traceable to the reliance on the new
theory of reference. To begin, there are familiar reasons to be
skeptical about whether the new theory of reference is correct,
reasons that won't be rehearsed here (see, e.g., Evans 1973,
Blackburn 1988). Even granting, however, the correctness of the new
theory, it is not obvious how it helps in the case of law. After all,
the new theory always seemed most plausible for a limited class of
expressions: proper names and natural kind terms. The reason has to do
with the implicit essentialism required for the new theory: unless
referents have *essential* characteristics--just as
"water" has a distinctive and essential molecular
constitution--they cannot fix meanings. But what is the essence
of "due process" or "equal protection?" And
what is the "essential" nature of the many artifact terms
that populate legal rules (terms like "contract" or
"vehicle" or "security interest")?
Unsurprisingly, S-naturalists like Brink and Moore are also moral
realists, and also try to give accounts of artifact terms as picking
out not "natural kinds" but "functional kinds"
(Moore 1992a, pp. 207-208).



Of course, even if the new theory of reference gives the correct
account of the meaning of some terms (like natural kind terms), that
still does not show that it gives us the right account of meaning for
purposes of legal interpretation (cf. Munzer 1985). Suppose the
legislature prohibits the killing of "fish" within 100
miles of the coast, intending quite clearly (as the legislative
history reveals) to protect whales, but not realizing that
"fish" is a natural kind term that does not include whales
within its extension. The new theory of reference tells us that the
statute protects sea bass but not whales, yet surely a court that
interpreted the statute as also protecting whales would not be making
a mistake. Indeed, one might think the reverse is true: for a court
*not* to protect whales would be to contravene the will of the
legislature, and thus, indirectly, the will of the people. What the
example suggests is that the correct theory of legal interpretation is
*not* a mere matter of philosophical semantics: issues about
*political legitimacy*--about the conditions under which
the exercise of coercive power by courts can be justified--must
inform theories of legal interpretation, and such considerations may
even trump considerations of semantics.