We Are All Naturalists Now
It is no easy task to say what naturalism in epistemology or in ethics is. In fact, it is almost surely a mistake to think that any particular view or thesis uniquely deserves the title. There are, instead, a variety of views and attitudes that are described as naturalistic. What they share may well be nothing more than a vague and general attitude toward philosophy, a key part of which is a desire to make philosophy closely connected to science. This desire can play itself out in at least two ways. One concerns views about the content of ethical and epistemological claims. Roughly, naturalists contend that philosophically significant statements have contents that are scientifically respectable. They are not about some ethereal realm. The second way the desire to naturalize philosophy plays itself out concerns methodology. The central idea here is that the methods for investigating philosophical issues are similar to, or identical with, those used to investigate scientific issues. The specific parts of philosophy under discussion in today's symposium, epistemology and ethics, are, on this approach, parts of, or at least importantly connected to, natural science. I will call the first of these kinds of naturalism substantive naturalism because it involves claims about the nature or substance of ethical and epistemological judgments. I will call the second sort of naturalism methodological naturalism, since it makes claims about the appropriate methods for investigating epistemological and ethical issues. My discussion will focus primarily on epistemological naturalism, though ethical naturalism will surface from time to time.
I. Substantive Naturalism
A. Ethical Facts, Epistemic Facts, and Natural Facts
In a discussion of naturalism in ethics Gilbert Harman writes:
[Ethical naturalism] is the doctrine that moral facts are facts of nature. Naturalism as a general view is the sensible thesis that all facts are facts of nature.(1)
On Harman's view, then, the general naturalistic thesis is thus:
NAT. All facts are natural facts.
In this section I will be concerned primarily with epistemological naturalism, understood as a special case of (NAT):
E-NAT. All epistemic facts are natural facts.
Ethical naturalism, the view that ethical facts are natural facts, will come up from time to time. Of course, (E-NAT) is not informative unless it is supplemented with some account of what counts as a natural fact. One view is that the natural facts include all the facts that a complete science will acknowledge. Another way to characterize the natural facts is to provide a list of representative examples of the sorts of things that count as natural, with the hope that we have at least a reasonably good idea of what else might be included. The two approaches are not incompatible, since the examples might be a list of the sorts of facts science acknowledges. One such list was produced by Alvin Goldman in his classic paper, "What is Justified Belief?" Goldman was not explicitly discussing naturalism in this paper. Rather, he was discussing the non-epistemic conditions that determine when a belief is justified. Toward this end, he identified a set of non-epistemic terms. Still, the things he mentions will serve present purposes quite well. Goldman says that the following are non-epistemic terms:
'believes that', 'is true', 'causes', 'it is necessary that', 'implies', 'is deducible from', and 'is probable (either in the frequency sense or the propensity sense). In general, (purely) doxastic, metaphysical, modal, semantic, or syntactic expressions are not epistemic.(2)
Call this the "N-list". This list is obviously incomplete, and there are things about it that one might question, but it is a useful starting point.
Obvious questions arise for defenders of (NAT) when they turn their attention to ethics and epistemology. Goldman also provides a list of epistemic terms, the terms that need reduction or explanation in natural, or non-epistemic terms. He mentions:
'justified', 'warranted', 'has (good) grounds', 'has reason (to believe)', 'knows that', 'sees that', 'apprehends that', 'is probable' (in an epistemic or inductive sense), 'shows that', 'establishes that', and 'ascertains that'.(3)
Goldman notes that analogous things could be said about moral terms such as 'right'. Presumably, the thing that unifies the epistemic and moral terms is that they involve something evaluative. They seemingly do more than merely describe how things are, but they say how something is to be evaluated in some domain. Call the list of evaluative epistemic and ethical terms the "E-list".
Ethical and epistemic sentences are sentences using terms from the E-list. We say that a person is justified in believing one proposition, has good grounds for another, knows that something is true, and so on. We say that certain actions are right and that others are wrong. Philosophically significant sentences using terms from the E-list provide the basis for a simple argument against (NAT):
1. Sentences using terms from the E-list report facts.
2. These facts are not natural facts.
3. So, there are some non-natural facts.
One way to defend (NAT) from this argument is to reject (1), arguing that ethical and epistemic sentences do not report facts at all. Defenders of such a view might contend that the sentences are sheer nonsense. More plausibly, they might argue that they are meaningful but non-factual, perhaps because they are expressions of approval or disapproval of the beliefs and believers or the acts and actors mentioned. There have been some defenses of this view, more frequently in ethics than in epistemology. I will not discuss it further here. My focus will be premise (2).
B. Definitions
We can take a definition of a term to be a statement of logically necessary and sufficient conditions for its application. It is, of course, possible to demand more of a definition - concept or property identity, perhaps. For present purposes it will suffice to consider the weaker notion.
Familiar accounts of epistemic and ethical terms seem to be divisible into those that employ only clearly naturalistic terms and those that do not. Many traditional definitions of epistemic justification make essential use of other evaluative epistemic terms. Thus, it is common to define justification in terms of good reasons, adequate evidence, strong grounds, the right to be sure, and the like. These definitions of epistemic terms use other terms from the E-list.
My own favorite account of justification, evidentialism, is squarely in this category. According to evidentialism, a person is justified in believing a proposition at a time if and only if the evidence the person has at that time supports believing that proposition (rather than disbelieving it or suspending judgment about it). This definition appeals to two crucial elements: the evidence a person has at a time and the support relation that can hold between a body of evidence and an attitude toward a proposition.
There is no reason for naturalists to worry about the naturalistic credentials of the idea of evidence possessed. This is not to say that the concept is entirely clear. But there is nothing metaphysically spooky, or even evaluative, about it. The evidence one possesses is some combination or other of the experiences one is having, the memories one has, and the other beliefs one has. It may be that other beliefs count as evidence only if they themselves are justified, but this at most shows that the account of justification will turn out to be recursive. It does not show that this element of the evidentialist definition invokes anything non-natural.
The second component of the evidentialist definition of justification is the idea of evidential support. It is easy enough to give examples of cases in which this relation is supposed to obtain and other cases in which it does not obtain. There may also be some cases that are difficult to assess. Despite this, its naturalistic credentials are in doubt. Evidential support seems to be precisely the sort of relation that Goldman sought to exclude from the base clause in his account. A body of evidence supports believing a proposition just in case the evidence is a good reason to believe the proposition or is good evidence for it. So "supports" as evidentialists use the term is clearly on the E-list.
There are other accounts of epistemic terms that also use terms that raise the suspicions of naturalists. These are definitions of epistemic justification in terms of duties or rights, definitions that treat justification as a deontological concept. I will not discuss deontological concepts here, although I think many of the points raised below apply equally well to them. Evidentialism, then, will be the representative account of justification that appeals to seemingly non-natural terms.
In contrast to evidentialism are causal and reliabilist accounts. The simplest version of the causal theory says that a belief that p is justified when the fact that p is causally connected to the belief that p. This theory invokes facts, beliefs, and causal connections, all terms expressed by items on the N-list. Of course, the simplest version of the causal theory is implausible. More sophisticated revisions invoke the worrisome notion of an "appropriate" sort of causal chain. But we may assume that appropriateness can be cashed out in some acceptable way and that the causal theory is unquestionably naturalistic.
Reliabilism also seems, at least at first glance, to invoke only naturalistically respectable terms. It holds that a belief is justified provided it is produced by a belief-forming process that reliably leads to true beliefs. There are considerations that can lead reliabilists to modify this account. Some of them might introduce elements that test a naturalist's scruples, but I will not press the point here. We can safely assume that reliabilism provides an account of the necessary and sufficient conditions for justification that invokes only terms on the N-list.
Suppose a philosopher accepts one of the evidentialist or deontological definitions and rejects the clearly naturalistic definitions just mentioned. Does it follow that that philosopher is committed to some puzzling sort of non-naturalism? I think that the answer is "No." Some philosophers have argued that the terms on the E-list supervene on those on the N-list, and one might think that this sort of supervenience is sufficient to show that all epistemic facts are natural facts. I will discuss and reject this line of thought in the next section. I will then turn to a reply according to which evidentialist accounts of justification are naturalistic as stated, or that further analysis of the terms involved will yield naturalistic definitions.
C. Supervenience
A very widely accepted view is that evaluative ethical and epistemic facts supervene on naturalistic ones. To say that the evaluative facts supervene on the natural ones is to say that in any two worlds in which all the natural facts are alike, all the evaluative facts are also alike.(4) Alternatively, one might say that facts about the epistemic status of beliefs supervene on natural facts provided that, necessarily, if two believers share all the same natural properties, then same beliefs are justified for them.
Here are some representative assertions of a supervenience thesis:
...if a belief is justified, that must be so because it has certain factual, non-epistemic properties...That it is a justified belief cannot be a brute fundamental fact... [it] must be grounded in the factual descriptive properties of that particular belief.(5)
Add quotes from Goldman, Chisholm, Sosa, Van Cleve.
There is, of course, considerable disagreement about which facts are central to the supervenience base for epistemic facts. This corresponds to the differences in the definitions discussed in the previous sections. Evidentialism holds that the key natural facts that determine whether a belief is justified are facts about the evidence the person has for that belief. The evidence one has is some combination or other of the experiences one is having, the memories one has, and the other beliefs one has. All of these are unquestionably natural facts about a person. And evidentialism holds that necessarily, people who have the same evidence are justified in believing the same things. In other words, the theory is that natural facts about evidence possessed determine epistemic facts. So, on an evidentialist view, epistemic facts do supervene on natural facts. Reliabilism holds that the crucial facts in the supervenience base of epistemic facts are facts about the reliability of the causal produce producing or sustaining the belief. These too are unquestionably natural facts.
There are a few philosophers who deny the supervenience thesis. One who does is Keith Lehrer.(6) It is possible to interpret Alvin Plantinga's views in ways that imply the denial of supervenience. This depends upon details about his views that need not concern us here.(7) So, almost everyone accepts the supervenience thesis. Thus, is the truth of supervenience thesis now under discussion sufficient to support (E-NAT)?
We are part of the way toward a defense of an affirmative answer to this question if the following thesis is true:
S. If fact F supervenes on natural facts, then F itself is a natural fact.
The obscurity of the concept of naturalness make it difficult to argue for (or against) (S). But we can make use of some of the things participants to the debate say as at least indicative of what the naturalism/non-naturalism issue is supposed to be. And this seems to provide some support for (S). In an extensive review of naturalism in epistemology, James Maffie writes that:
epistemic value is anchored to descriptive fact, no longer entering the world autonomously as brute, fundamental fact...(8)
One can find comparable claims in the writings of many others.(9) If epistemic and ethical facts supervene on unquestionably natural facts, then they do not float free, they are not autonomous, they are not brute facts, they are anchored in the natural world. That seems like a pretty good reason to conclude that they are natural facts.(10)
There is, then, a simple argument for substantive naturalism, at least with respect to epistemic facts. An analogous argument could be given concerning ethical facts. The argument in the case of epistemology is simply:
1. If fact F supervenes on natural facts, then F itself is a natural fact.
2. All epistemic facts supervene on natural facts.
3. Epistemic facts are natural facts.
Some critics may object to (1) (or (S)). The issue turns on the difference between definition and supervenience. If evaluative epistemic facts merely supervene on descriptive facts and have not have not been defined in terms of them, then perhaps the evaluative facts have not been reduced or eliminated. An analogous point can be made in any case of supervenience. According to this line of thought, if sentences using terms from the E-list report natural facts, then the terms from the E-list must be definable in naturalistic terms. Mere supervenience is not enough. Perhaps some support for rejecting (S) comes from the fact that (S) yields the surprising result that the famous ethical non-naturalists were actually naturalists. For example, G. E. Moore would have endorsed the supervenience thesis. Kim says that we use the term "naturalist" ambiguously in "ethical naturalism" and "epistemological naturalism". The former requires definitions in natural terms. The latter requires only supervenience.(11)
I believe, however, that for purposes of deciding whether (E-NAT) is true, we need not determine whether (S) is true. Even if we grant (S), there remains reason to doubt (E-NAT). This is because there remain some epistemic facts whose status is still in doubt. According to evidentialism, there are facts about what beliefs are supported by a particular body of evidence. These are thought to be necessary truths, and it is their necessity that enable evidentialists to endorse a strong supervenience thesis. Thus, as evidentialists see it, necessarily, if a person has some body of evidence E, then that person is justified in believing proposition P. The sentences expressing these epistemic relations express facts - we can call them epistemic support facts. It is legitimate to ask whether they count as natural facts. If not, then, given (S), contingent epistemic facts about the status of individual beliefs may be natural facts, but the epistemic support facts may not be. So the supervenience claims so far discussed are not sufficient to defend (E-NAT) from the stated objection.
If the epistemic support facts are not natural facts, then not all epistemic facts are natural facts and (E-NAT) is false. If the epistemic support facts are natural facts, and justification is defined in terms of evidence possessed and epistemic support, then justification is defined in entirely natural terms. In that case, evidentialists do not need to rely on (S) to support (E-NAT). They can defend (E-NAT) on the grounds that they have given naturalistic definitions of epistemic terms.(12)
Defenders of (S) can use (S) to argue that epistemic support facts are natural facts. Epistemic support facts are, on many views, necessary truths. (More on this below.) On standard definitions of supervenience, it is trivial that necessary truths supervene on natural facts. (They supervene on anything.) Given (S), it would follow that they are natural facts. I will ignore this line of thought in what follows. I will argue that evidentialists have good reason to claim that epistemic support facts are natural facts without appeal to (S).
D. Naturalistic Definitions
Defenders of evidentialist accounts are not (or at least need not be) committed to the idea that no naturalistic definitions of the terms they employ in their definitions are possible. It may be that they just have not produced such definitions yet. And even if the terms are not strictly definable, it does not follow that they are not themselves perfectly good naturalistic terms.
It is clear that the N-list as stated is radically incomplete. It is also clear that there are very hard questions about exactly how it is to be extended. A huge number of other seemingly unproblematic terms are also not definable by means of the terms explicitly on the N-list. This is a consequence of the unfortunate fact that we seem to have learned in recent years: hardly anything is definable. We can't come up with necessary and sufficient conditions for familiar terms such as "money", "table", "happy", "student", and so on. I take it that these are naturalistically acceptable terms.(13) Presumably, then, these terms are themselves on the N-list. This suggests that the N-list includes a variety of "higher level" terms that cannot be strictly defined in terms of fundamental physical terms. This in turn suggests that we take a closer look at some of the items on the E-list, and think about whether some of them really are naturalistically suspect.
The central question I will discuss in this connection concerns whether the evidential support relation is a natural relation. There is, however, a details about how evidentialist theories are developed that requires attention. Richard Fumerton contends that what is required for inferential justification is "acquaintance" with facts regarding epistemic support relations.(14) One might also say that a person's evidence supports a proposition just in case the person perceives or grasps or understands the connection between that evidence and that proposition. If anything like this view is correct, the epistemic support relation is to be understood as a complex of some logical (or quasi-logical) relations and some psychological relations.
There are, then, two slightly different ways one might construe evidentialism. On one view, whether a belief that p is justified depends on what evidence one has and whether that evidence supports that belief. The latter is taken to be a relation between the evidence and the proposition p. This evidential support relation is not in any way relative to or dependent on the capacities of the believer. On the other version of evidentialism, a person is justified in believing p just in case the person has evidence that supports the belief and the person grasps or is acquainted with this connection. On this second alternative, two people could have the same evidence, yet only one of them might grasp its connection to some proposition, and thus only one of them would be justified in believing that proposition. The difference between these two views may not amount to much, since defenders of the former view might think that grasping the connection is, in effect, part of the relevant evidence. In any case, it will be helpful to be aware of these two ways in which evidentialism might be worked out.
Consider, then, Fumerton's idea that inferential justification requires acquaintance with epistemic support relations. As noted, there are two ideas here: epistemic support and acquaintance. Naturalists might worry about each. I think that they shouldn't. Consider acquaintance first. One might wonder whether we really do have the ability to "grasp" relations between evidence and propositions. One might doubt that we actually are acquainted with such relations in the way Fumerton's view requires. However, it is indisputable that something along these lines really does exist. We do in some sense or other recognize certain connections and fail to recognize others. There may be legitimate doubt about whether the sort of relation that surely obtains is adequate to make evidentialism a correct account of justification. But if Fumerton, and evidentialists generally, say that there is a special sort of grasping or understanding or acquaintance whose existence others deny, it is seriously misleading to attribute some sort of non-naturalism to them. They are making a claim about what natural relations there actually are. Fumerton's view is that acquaintance is a particularly fundamental sort of psychological, hence natural, relation. If we never stand in that relation to anything, and justification requires it, then we are never justified in our beliefs. The difference between evidentialism and rival views may be in part over what natural properties there actually are. There is no reason to characterize grasping or acquaintance as a non-natural relation.
The issue here is something like an issue that arises in discussions of extra sensory perception. Clear-headed defenders of the view that we are capable of perceiving things that ordinary psychology would declare us incapable of perceiving differ with their opponents over what natural relations (or abilities) we have. While some may try to cast their view in mystical language, there is no reason to invoke non-naturalism here. If a hard-headed naturalist became convinced that some people did have some abilities previously thought to be beyond us, the response should be a change in views about what nature is like, not a renunciation of naturalism.
The second reason naturalists might be suspicious of the account of evidential support in terms of grasped evidential connections concerns the logical relations involved. Deductive and probabilistic connections are typically said to be naturalistically acceptable (although one might wonder why). But it is common for epistemologists to say that epistemic relations differ from these relations. One good reason for saying this is the fact that the existence of a logical relationship between a body of evidence and a proposition is not sufficient for the existence of an evidential relationship. The mere fact that one's evidence logically implies some conclusion does not make it reasonable for one to believe that conclusion on the basis of that evidence. The logical connection may be extremely complex, beyond the grasp of some or all believers. This consideration, however, suggests only that evidence supports a conclusion for a person only if the person sees the connection between the evidence and the conclusion. In other words, the psychological relation - grasping the connection - is necessary.
An even more troubling thing epistemologists say about epistemic support is that it obtains in cases in which there is no standard logical or probabilistic relation. Epistemic support, they say, is new kind of relation. The reasons for saying this can be seen by considering some epistemic principles some philosophers have defended. Chisholm, for example, has endorsed principles such as:
R1. If S seems to see something red before him, then S is justified in believing that something is red before him.
We can restate the idea behind a principle such as this one in terms of a relation that holds between an experiential state and a proposition:
R2. Being in the state of seeming to see something red (being appeared to redly) is evidence for the proposition that one really does see something red.
The evidential support described in (R2) is, of course, defeasible. One could have evidence that one is not really seeing something red in spite of being appeared to redly. The key things about this principle are that it relates being in an experiential state to a proposition. Thus, the relation does not involve two propositions. It relates an experience to a proposition. This reflects the common idea that experiences somehow are part of our evidence for our beliefs about the world around us. This suggests that epistemic support is not any familiar logical relation, since it does not relate only propositions.
The second key thing about (R2) is that it is not, or at least not obviously, an instance of some general deductive or probabilistic principle. It is not the case that (R2) is true because it is necessarily or even usually the case that one does see something red when one is in the specified state. Chisholm says that "there are principles of evidence other than the formal principles of deductive logic and inductive logic."(15) Thus, at least some evidentialists seem to be committed to there being fundamental epistemic principles, or evidential support relations, that differ from any deductive or probabilistic relations and cannot be defined in terms of any complex of psychological relations and familiar logical relations. There are, on this view, irreducible epistemic relationships between propositions or between experiences and propositions. And it is these relations that evidentialism requires us to grasp or be acquainted with.
Defenders of evidentialism are not forced to say that principles such as (R2) are not special cases of naturalistically acceptable general principles. One could argue that (R2) follows from some general principle about best explanations. Thus, one might argue that something along the lines of (R2) is true because the proposition mentioned is part of a best explanation of the experience mentioned. And this relation, arguably, is naturalistically acceptable. Epistemologists are not without other defenses of principles in the vicinity of (R2). Appeals to conservatism (what we already believe), what we naturally believe, what is generally accepted, and other factors are possible. Philosophers who endorse any such view can proudly proclaim themselves naturalists.
Still, it must be admitted that Chisholm himself would not accept any such view. Apparently, he thought that there were fundamental epistemic principles that could not be explained in any such terms. This is a view that is apt to give naturalists grounds for concern. Perhaps this counts as non-naturalism. But even here, I find it difficult to understand exactly why. Chisholm apparently thought that, in addition to deductive and probabilistic connections, there was another species of connection between propositions (or between experiences and propositions). His view was that these relations are part of the real, or natural, world. Some may deny that there are any such relations. This seems, once again, to be a dispute about what there is, not a dispute about whether there is something beyond what is natural. In other words, if Chisholm is right, it is quite unclear why terms such as "supports" and other epistemic terms do not belong on the N-list in the first place. If they do, then even Chisholm can plausibly maintain that epistemic support facts are natural facts.
There is, then, little that emerges from an examination of the various accounts of epistemic justification that provides a basis for claiming that any parties to the dispute are committed to substantive non-naturalism. It is true that defenders of evidentialist and deontological accounts of epistemic terms typically do not provide definitions making use only of clearly naturalistic terms. But it does not follow that epistemic relations are not themselves natural relations or that naturalistic definitions of them are ruled out in principle.
Thus, even if naturalism requires that there be naturalistic definitions (necessary and sufficient conditions) for epistemic terms, I don't see why traditional evidentialist views should be described as nonnatural. They may appeal to different natural facts and relations in explaining epistemic justification, but they are no less natural for that.
II. Methodological Naturalism
A. Preliminaries - Quine
By most accounts, the source of contemporary naturalism in epistemology is the work of W.V.O. Quine, particularly his essay, "Epistemology Naturalized."(16) Quine begins this essay by discussing attempts to derive statements about the world around us from statements about our own sensations. Quine argues that such efforts to ground our beliefs about the world have failed. In the light of this failure, Quine seems to recommend that we instead study the psychological processes by which we form our beliefs about the world. As Jaegwon Kim points out in a justly famous critical discussion of Quine, a conspicuous difference between traditional epistemology and what Quine recommends is that they study strikingly different topics.(17) The old epistemology was interested in questions about rationality, justification, and knowledge. The questions that most intrigued the old, or traditional, epistemologists were questions about what exactly it was to know something and whether we really did have knowledge in the range of cases in which we ordinarily thought we did. One way to think of these questions is as questions about whether an epistemic support relation--a justifying relation--holds between our basic evidence and our beliefs about the world. Epistemology thus prominently includes evaluative questions, questions about the quality of evidence. As Kim sees it, Quine has proposed ignoring these evaluative questions and investigating instead the causal connections between our sensory evidence and our beliefs about the world. Thus, if we follow the Quinean recommendation, we'll study the same relata--our basic evidence and our beliefs about the world. However, we will study a different relation. In the original case, we looked to see if there was an epistemic support relation between the data and the beliefs. In the new case, we look to see the nature of the causal connection between them.(18)
The Quinean view that we should abandon epistemology for psychology is not widely accepted by contemporary naturalists in epistemology. However, a more modest descendant of his view is extremely popular. This current view holds that, while there are evaluative questions to pursue, empirical results from psychology concerning how we actually think and reason are
essential or useful for making progress in addressing evaluative questions. I will call this view "Methodological Naturalism," to contrast it with the "Replacement Naturalism" advocated by Quine.
Methodological naturalism has many advocates, as can be seen from the following claims:
"Thus, a mix of philosophy and psychology is needed to produce acceptable principles of justifiedness."(19)
"....any epistemologist who rejects skepticism ought to be influenced in his or her philosophical work by descriptive work in psychology."(20)
"... the results from the sciences of cognition may be relevant to, and may be legitimately used in the resolution of traditional epistemological problems."(21)
"[Philosophers] . . . ignore [recent experimental work about human reasoning] at their own peril."(22)
"[I]t is hard to come up with convincing normative principles except by considering how people actually do reason, which is the province of descriptive theory."(23)
No doubt the philosophers just quoted were engaged in different epistemological projects and their views about the exact role psychology might play in their efforts differed accordingly.(24)
As soon as one begins thinking about the connection between epistemology and psychology, one is confronted with a difficult question: What counts as epistemology? The answer affects the plausibility of methodological naturalism considerably. There is no doubt that if epistemology is as expansive a discipline as some think, then methodological naturalism is true. Philip Kitcher, another advocate of methodological naturalism, asks, "How could our psychological and biological capacities and limitations fail to be relevant to the study of human knowledge?"(25) Obviously, empirical work is relevant to "the study of human knowledge." But this shows its relevance to epistemology only if epistemology is itself as broad as the study of human knowledge. The complete study of human knowledge would, presumably, include historical studies of what people knew when and how knowledge has grown (or been lost) over time, studies in neuroscience concerning the ways the brain processes information, psychological studies of the cognitive processes involved in belief formation, sociological studies about the ways knowledge is transmitted in societies, and so on. While some philosophers may think that they have something to say from their armchairs about many of these topics, no sensible person could think that all such inquiries can succeed without scientific input. So, it is hard to imagine any disagreement with the view that methodological naturalism is true given such a broad interpretation of what counts as epistemology. However, if epistemology addresses only the philosophical questions about knowledge, rationality, and justification, then presumably it addresses something less than the complete "study of human knowledge."
In the remainder of this paper I want to examine methodological naturalism as it applies to a few issues typically addressed by epistemologists.
B. Methodological Naturalism and The Extent of Our Knowledge
A great deal of epistemology is devoted to questions about what people know. The goal, of course, is not to produce a list of all the facts anyone knows, but rather to discuss the kinds of things people know, especially in the light of arguments for the skeptical conclusion that people know little or nothing. Sometimes the questions are framed as questions about what people can know. Is there a dispute between naturalists and non-naturalists about the answers to these questions, or about the means to arriving at answers?
In the discussion that follows it will be helpful to be aware of the fact that there are three views about the potential sources of information for epistemological theorizing, rather than the two that are sometimes identified. There is, first of all, the idea that there is some apriori knowledge to bring to bear on the issues. There is, second, the idea that results from empirical psychology and cognitive science are somehow relevant. And, finally, there is the idea that common sense information we all have about the world around us is relevant. This last includes the sort of thing we can know from our armchairs. The significance of this third category will emerge as we proceed, but it is worth noting we can divide philosophers into at least three groups, depending upon their views about the relevance of this sort of material. Thus, philosophers who think that epistemology is entirely an apriori discipline contend that information from the first category alone is needed or useful. We can call them apriorists. We can call those who rely on common sense empirical knowledge, but not scientific results, armchair epistemologists. And scientific epistemologists proclaim the value of (or need for) the results from empirical studies for epistemology. It is possible for some scientific epistemologists to argue that only empirical results are relevant to any epistemological questions. I predict that any defense of that sort of view would at the very least make use of some reasoning that can not by any stretch of the imagination be described as entirely scientific, so that view seems hardly in need of consideration.
This three way classification complicates the discussion in certain ways. In some discussions of naturalism it seems that the chief aim is to reject the idea that epistemology is a purely apriori affair.(26) But armchair epistemology is not a purely apriori affair, so it would turn out to be naturalistic, if naturalism were equated with the denial of apriorism. Sometimes, however, the idea seems to be that naturalistic epistemology is epistemology that makes heavy use of empirical scientific results. Since armchair epistemology does not make heavy use of scientific results, it turns out to be a kind of non-naturalism, on this second way of dividing things up. I will not argue that one of these ways of characterizing naturalism is the "correct" one. It will be enough to notice these differences.
Claims to the effect that actual people know actual facts about the world are contingent propositions about the world. They cannot be known apriori. Even in the first person case, one cannot have apriori knowledge that one knows contingent things about the world. If one could, then, given that knowledge implies truth, one could have apriori knowledge of the facts known. Thus, if I could know apriori that I know that material bodies exist, then I can know apriori that material bodies exist. I assume that such things cannot be known apriori. Contingent empirical information, perhaps information available to us in our armchairs, must play a role in our arriving at any such conclusions. So, if it is part of epistemology's job to say whether or not there is knowledge in particular actual cases, it is surely not an apriori matter.
And it is almost surely not a matter to which information from empirical sciences can be wholly irrelevant. We might judge from our armchairs that we have knowledge in some range of cases. It is possible that cognitive science will discover that in some or all of these cases our beliefs result from bizarre, thoroughly unreliable, deviant causal chains. I think that in those cases we would learn that we lack knowledge in cases where we thought we had it. Though the possibility that we will learn such things in a variety of familiar cases is extremely small, it is not zero. So empirical results could overturn our judgments about these cases.
Thus, if it is epistemology's business to make judgments about whether actual people have knowledge in actual cases, and naturalism is the view that empirical information from the natural sciences is potentially relevant to those judgments, then naturalism is unquestionably true. What would be remarkable about this is that anyone ever denied it.
It would be a mistake, however, to conclude that scientific information is needed to know anything, even anything about knowledge. We can know a lot from our armchairs. It is difficult to see why we cannot know some things about knowledge from our armchairs. This claim obviously assumes that philosophical arguments for skepticism fail. I turn to that topic briefly.
Arguments for skepticism typically include premises of two sorts. Premises of one sort specify some necessary condition for knowledge. Premises of the other sort say that people's beliefs never, or rarely, satisfy that necessary condition, or perhaps that they can't satisfy that condition. To the extent that an evaluation of the skeptical argument focuses on a premise of the first sort, armchair epistemologists will be in a position to carry out the task. A good analysis of knowledge will enable us to determine whether knowledge really does have the necessary condition the argument describes. To the extent that the evaluation focuses on a premise of the second sort, it will typically require empirical information, often information that will come from natural science. Of course, sometimes that empirical information will also be available to intelligent epistemologists in their armchairs, since it may not depend on technical results from psychology. Different arguments for skepticism may require different sorts of responses. For example, some arguments for skepticism hold that for knowledge, or justification, we must have absolute certainty. In my view, we can refute these arguments on apriori grounds. But other arguments could be devised that can not be set aside in that way. For example, it is possible to argue that empirical studies reveal serious, widespread errors in our beliefs about a given topic, that all our beliefs in this domain result from the same kind of faulty thinking (even if we once in a while get things right), and thus that we have no justified beliefs in that domain. Empirical results are likely to be central to the evaluation of any such arguments.
I conclude that if epistemological issues include making judgments about whether actual people have knowledge in real or realistic cases, then empirical information of both the armchair and scientific varieties is potentially relevant. So if methodological naturalism is the view that empirical information is relevant to these questions, then it seems to me indisputably true. Indeed, it is hard to imagine anyone disagreeing. Again, if this is naturalism, we all are (or should be) naturalists now. I see no reason for philosophers who agree that this is part of philosophy to dissent from this conclusion.
C. Non-naturalism, Common Sense, and Epistemic Improvement
One complaint about allegedly non-naturalistic epistemology voiced by some advocates of naturalistic epistemology is that non-naturalism somehow merely endorses our pretheoretic intuitive judgments whereas naturalism allows for genuine advances in our understanding because it makes use of sometimes surprising empirical results that non-naturalists ignore.(27) I want to explore this charge in this section.
One source for this kind of charge can be found in a claim made by many epistemologists, typically those identified as non-naturalists. The claim, or assumption, they make is that we know pretty much what we think we know. A representative formulation of this approach can be found in John Pollock's Contemporary Theories of Knowledge. Pollock writes:
In typical skeptical arguments, we invariably find that we are more certain of the of the knowledge seemingly denied us than we are of some of the premises. Thus it is not reasonable to adopt the skeptical conclusion that we do not have that knowledge. The rational stance is instead to deny one or more of the premises.(28)
Pollock goes on to say contemporary epistemologists largely see figuring out what knowledge is as their goal, rather than refuting skepticism. As he puts it,
we "need not refute the skeptic - we already know that the skeptic is wrong."(29)
This view, of course, has its similarities to views endorsed by G. E. Moore, and it is by no means uncommon. More generally, many epistemologists proceed on the assumption that we do know pretty much what we think we know, and thus on the assumption that skepticism is false. They proceed to discuss the implications of this assumption. It may seem that this position, or this attitude, rules out the possibility that empirical results will overturn their philosophical starting point.(30)
It seems to me that this sort of outlook is best taken at most toward purely philosophical (apriori) arguments for the conclusion that no one knows anything, or perhaps for the conclusion that no one could know anything, in a given domain. Suppose a philosopher begins philosophizing by identifying a set of actual cases of knowledge. For example, I often begin a course by listing a number of things that I think I know and that I justifiably believe. One such belief might be my belief that I drank tea for breakfast today. It would be preposterous to maintain that there is nothing I could possibly learn from cognitive science that would lead me to retract the belief that this belief of mine is justified. Surely I could learn a variety of things about cognitive failures generally, or in my own case, that would lead me to conclude, quite justifiably, that this belief is not justified after all.
I think that the Moorean assumption is better taken to be a position toward highly abstract philosophical arguments for skepticism, typically arguments that imply that we lack knowledge no matter what the facts in the world are. It may be a mistake to reject these arguments out of hand. But whatever we say about such arguments, it would be mistake to attribute to Pollock, Moore, and others who share their views the idea that specific claims about what we know can not be overthrown on the basis of empirical information. Surely nothing about their philosophical positions requires them to maintain that extreme view.
There is a second basis for the charge that the views typically characterized as non-naturalism lead epistemologists to ignore valuable empirical information. One clear statement of this line of thought comes out in Philip Kitcher's 1992 article, "The Naturalists Return." This is a long and comprehensive study of naturalism in epistemology, arguing in part that the apsychologistic tendencies of the 20th century are in fact departures from what was standard in philosophy. Kitcher takes non-naturalists to hold that "our favored logical principles are prescriptions for thought."(31) But he thinks that the mere fact that we favor certain logical principles is of no value in establishing that they are meritorious principles. Our principles are good ones only if they actually do enable us to attain our epistemic ends. "Simply asserting that [certain rules] unfold our conception of rationality will be beside the crucial point."(32)
Kitcher illustrates his point by means of Hume's problem of induction. Hume famously asked whether we have any good reason to believe the conclusions of our inductive arguments. We notice that all observed instances of some sort of object have had a certain property and we infer that the next object of that kind will have that property. Our premise does not entail our conclusion and it turns out that it is extraordinarily difficult to justify these inductive inferences in a way that does not illicitly rely on induction itself. One solution to the problem, associated with Peter Strawson, is that "adopting the inductive practices and principles that we do is constitutive of concept of rationality."(33) But, Kitcher asks, "why should we treat our current concept of rationality as privileged?"(34) After all, rival societies might have rival conceptions. Anti-inductivists could proclaim their practices rational because they are constitutive of their conception of rationality. As Stephen Stich asks, "Why should we care one whit whether the cognitive processes we use are sanctioned by [our] evaluative concepts?"(35)
Identifying armchair or apriori epistemology with this sort of pointless ratification of the status quo is widespread. While I won't argue that armchair epistemologists have done nothing to bring this charge on themselves, I think that the charge is seriously off target. I'll turn now to an explanation of why.
Why should we think that we can figure out good principles of reasoning simply by thinking about them? Could Strawson's answer to Hume possibly be a good one? It is important to distinguish highly general epistemic principles from more specific principles that are applications or special cases of the general ones. An analogy from ethics might be helpful here. Act utilitarians--those who hold that in any circumstance one ought to do that action among one's alternatives that maximizes utility--will hold that the general utilitarian principle is not a contingent or empirical matter. But they are also likely to hold that there are no true special moral principles about promise keeping, truth telling, or even taking lives. One ought to do those things when and only when they maximize utility. The only true general principles about these kinds of actions are simply special cases of the wholly general utilitarian rule. There are, however, useful rules of thumb, to the effect that certain sorts of actions typically do or don't maximize utility. Such rules of thumb may be helpful guides to life. Some such principles will be ones that we might have some fairly good information about while comfortably seated in our armchairs. But even these, as well as all others, will be subject to modification in the light of empirical information about what actually produces utility. Questions about the general utilitarian principle seem to me to be largely apriori. There is much about its application that we can gain reasonable belief about from our armchairs. And there is much that can be studied best in conjunction with results from the sciences.
It may well be that people are prone to make claims about the relative value of various actions without adequate empirical support for their views. That is, they may endorse rules of thumb when they have little basis for doing so.(36)
There are, I think, some clear similarities in the epistemic case. There are general apriori issues involving rival views about the nature of justification and knowledge. For example, there are questions about the role of reliability, the need for evidence, the connection between justification and responsibility, and so on. Some of these issues help frame general principles about justification. There are questions about how best to spell out specific theories, such as reliabilism, as well as questions about how to resolve the apparent conflicts between rival theories. It is hard to see any case at all for empirical input into these disputes.
Suppose that you have adopted some general approach toward the nature of justification. The application of the general principles will be largely a contingent empirical affair. There is much about the application of epistemological terms that can be learned in armchairs. For example, we might know that we are reliable with respect to memory or perception in certain sorts of contexts, and unreliable in other contexts. We have good reason to believe that guessing is not a reliable way to form beliefs about what the weather will be like tomorrow, but that listening to what the weather forecasters say is hardly better. And so on. Sensible beliefs about these matters can be refined, and perhaps revised, on the basis of serious scientific results.
To go back to Kitcher's charge that non-naturalists simply defend our existing principles by saying that they are constitutive of our concept of rationality. One way to view the issue about induction that Hume raised makes it a very general issue about whether it is ever reasonable to use past, or unobserved, cases as the basis for beliefs about future, or observed cases. The Strawsonian view he mentions says that it is, and defends this on the basis of claims about our concept of rationality. Kitcher takes this to be a defense of our adoption of the inductive practices and principles that we actually use. If the principles to which he refers are more specific principles licensing particular inductive inferences, then it may well be that the principles are analogues of the lower-level moral principles just mentioned. And it may well be that these principles require empirical input of one sort or another for their support. Philosophers who contend that these lower level principles are necessary consequences of our concept of rationality may well be mistaken. Still, Strawson may well have been right about the more general issue.
When Kitcher asks, "why should we treat our current concept of rationality as privileged?"(37) it is quite unclear what question he is asking. When we ask whether a particular belief is justified or whether there is knowledge in a particular case or whether it is rational to employ a particular method, we are using our concepts to raise our questions. If we want to be clear about our questions and reasonable in our answer, it is useful to get as clear as we can about the concepts involved. This is not to give the specific principles endorsed in our armchairs a privileged position. It's just to ask our question. In my view, then, our concept does not privilege the lower the level principles that I suspect Kitcher thinks should not be privileged. I agree that they need empirical support.
A question remains about whether there is anything of any value that can emerge from apriori, or armchair, reflection. Isn't everything, in the end, a question to be best answered by science? Hilary Kornblith has suggested that philosophizing in the way epistemologists often do about knowledge is something like philosophizing about aluminum. The only serious questions about aluminum, he thinks, are scientific questions.(38)
It's difficult to see, however, exactly why we should think that knowledge is relevantly like aluminum. For one thing, what we seek in the case of aluminum is an understanding of its physical constitution. We want to know what it is made of, how it interacts with other materials and why, and what we can use it for. Our analysis of knowledge does not call for an account of its physical constitution. It's doubtful that there is any such thing. We might also seek scientific analyses of physical processes, such as cell division. But knowledge isn't a substance like aluminum or a process like cell division. So, analogies such as these don't provide reasons to seek naturalistic analyses of knowledge.
Some topics and questions are amenable to armchair methods and some are not. It would be foolish to extend Kornblith's line of thinking to logical concepts such as validity or conjunction, to modal concepts such as necessity, or, I believe, to moral concepts such as obligation. Some concepts have a richer conceptual structure than others.(39) The fact that knowledge requires true belief seems beyond dispute, and this shows that it has at least this much conceptual complexity. What else it requires continues to be in dispute. Whether anything of interest will emerge from further analysis remains to be seen. In any case, the alleged analogy to aluminum provides no basis for thinking that armchair epistemology should be replaced by an empirical study of knowledge.
III. Conclusion
In this paper I've distinguished two varieties naturalism, substantive and methodological. I've argued that almost all epistemologists can reasonably be regarded as substantive naturalists, given almost any sensible account of what it takes to be a substantive naturalist. I take methodological naturalism to be the view that empirical information is useful or even necessary for answering philosophical questions. One traditional epistemological questions concerns about what people know. On any view about what knowledge is, empirical information is relevant to answering such questions. Finally, contrary to the charges of some critics, it's not true that even the most traditionally minded epistemologists are committed to ignoring empirical information about ways to improve our beliefs. So if naturalism includes the recommendation that we make use of such advice, I think almost all epistemologists can accept it.
Endnotes
1. Gilbert Harman, The Nature of Morality (New York: Oxford University Press, 1977), p. 17.
2. Alvin Goldman, "What is Justified Belief?"
3. "What is Justified Belief?" p.
4. This is strong supervenience, as some define it. The key point is that things in different worlds that are descriptive alike must be evaluationally alike. A weaker notion would say only that any two things in the same possible world that are descriptively alike must be evaluationally alike.
5. Jaegwon Kim, "What is Naturalized Epistemology?"
6. See Self-Trust, Chapter 3.[?] For discussion, see James van Cleve, PPR, December 1999. Van Cleve makes what a very strong case for the view that Lehrer provides no good argument against supervenience.
7. I assume that two individuals could share all the relevant natural properties, yet differ with respect to whether they are believing in accord with their design plan. This rests on the assumption that facts about the design plan need not be natural facts. If that's right, then, according to Plantinga's theory, they could be naturalistically alike, yet differ with respect to epistemic properties.
8. James Maffie, "Recent Work on Naturalizing Epistemology," American Philosophical Quarterly 27 (1990), pp. 281-93. The quotation is from p. 284.
9. See Matthias Steup, An Introduction to Contemporary Epistemology, (Upper Saddle River, NJ: Prentice Hall, 1996), Chapter 9. There are quotations from Kim, Goldman, Lycan, Chisholm.
10. At one point in Kim says that "where [naturalists] differ from their nonnaturalist adversaries is the specific way criteria of justification are to be formulated. Naturalists and nonnaturalists ("apsychologists") can agree that these criteria must be stated in descriptive terms-that is, without the use of epistemic or any other kind of normative terms. According to Kitcher, an apsychologistic theory of justification would state them primarily in terms of logical properties and relations holding for propositional contents of beliefs, whereas the psychologistic approach advocates the exclusive use of causal properties and relations..." So in this passage he seems to locate the difference between naturalism and nonnaturalism in the kinds of descriptive properties one appeals to, with nonnaturalists appealing to logical properties and relations. I am assuming that naturalists can allow logical properties and relations, and Kim seems to as well. See the beginning of section 7 of his paper, where he seems to say that naturalism requires only that the evaluative supervene on the descriptive.
11. End of section 6.
12. Of course, if reliabilists also say that there are epistemic support facts, then they have to say something about the status of such facts. It is not clear to me whether they would say that talk about good reasons is really disguised talk about reliable processes, or nonsense, or non-factual, or non-natural.
13. [[Perhaps these are not natural kinds. What follows?]]
14. Add reference.
15. Roderick Chisholm, Theory of Knowledge 2nd Edition, (Englewood Cliffs, NJ, Prentice Hall, 1977), p. 67.
16. Quine, W.V.O., "Epistemology Naturalized," reprinted in Naturalizing Epistemology, 2nd edition, edited by Hilary Kornblith (Cambridge, MIT Press, 1994), pp. 15-31.
17. Jaegwon Kim, "What is 'Naturalized Epistemology'?" Philosophical Perspectives 2, edited by James E. Tomberlin (Atascadero, Ca., Ridgeview Publishing Co., 1988), pp. 381-406.
18. Quine says that he has not repudiated the normative in "Norms and Aims," The Pursuit of Truth (Cambridge, Harvard University Press, 1990?), pp.??
19. Goldman, Alvin, "Epistemic Folkways and Scientific Epistemology," reprinted in Naturalizing Epistemology, 2nd edition, edited by Hilary Kornblith (Cambridge, MIT Press, 1994), pp. 291-315. The quotation is from p. 314.
20. Kornblith, Hilary, "Introduction: What is Naturalized Epistemology?" Naturalizing Epistemology, 2nd edition, pp. 1-14. The quotation is from p. 14.
21. Haack, Susan, Evidence and Inquiry (Oxford, Cambridge University Press, 1993), p. 118.
22. Stich, Stephen and Nisbett, Richard, "Justification and the Psychology of Human Reasoning," Philosophy of Science 47 (1980): 188-202. The quotation is from p. 188.
23. Harman, Gilbert, Change in View: Principles of Reasoned Revision (Cambridge, MIT Press, 1986), p. 7.
24. Haack, for example, is generally less enthusiastic about naturalism than the other authors cited.
25. Philip Kitcher,"The Naturalists Return," The Philosophical Review 101 (1992), pp. 53-114. The quotation is from p. 58.
26. Add references.
27. See Kornblith, in Blackwell Guide to Epistemology. See also Kornblith's "How Internal Can You Get?" Synthese, 1988; reprinted in Kornblith, ed., Epistemology: Internalism and Externalism, Blackwell, forthcoming.
28. John Pollock, Contemporary Theories of Knowledge (Totowa, NJ, Roman and Littlefield, 1986), p. 6.
29. Ibid., p. 6.
30. For discussion, see Kornblith, "How Internal Can You Get?" originally in ??, reprinted in Hilary Kornblith, editor, Internalism and Externalism, Oxford, forthcoming.
31. "The Naturalists Return," p. 63.
32. Ibid.
33. Ibid.
34. Ibid.
35. The Fragmentation of Reason, p 92.
36. An example - recent discussions about the effects of divorce on children.
37. Ibid.
38. Hilary Kornblith, Blackwell Guide to Epistemology
39. For a defense of the use of intuitions about examples in doing philosophical analysis, see George Bealer, "The Incoherence of Empiricism," Naturalism: A Critical Appraisal edited by Steven Wagner and Richard Warner (Notre Dame, Notre Dame University Press, 1993), pp. 163-196.