The following is an informal precis of a larger paper that I'm currently working on. Any and all feedback would be very much appreciated:
Some traditionalists argue that empirical data are at best peripherally relevant to epistemology. They acknowledge that specific claims to knowledge are dependent, as a contingent matter of fact, on the reliability of the psychological processes that generate and sustain them, but they maintain that these details are relatively unimportant to epistemology.
Traditionalists argue that the real philosophical action takes place at the conceptual level. They argue that we must understand concepts like "knowledge" and "justification" by consulting our intuitions about the conditions for the proper applications of these concepts. The critical tests are thought experiments with N's of 1. Philosophers reflect on paradigm cases and attempt to recognize the factors that, say, differentiate knowledge from mere true belief. Then they test out their conditions by trying to formulate counterexamples in which the proposed criteria are met but the concept can't be applied. One such thought experiment is the scenario in which a person unwittingly acquires a reliable capacity for telepathy. Suddenly his mind is filled with true beliefs about what other people are thinking, but he doesn't know that he's telepathic. Would we say that he knows what other people are thinking?
This kind of philosophical methodology makes a lot of empirical assumptions about human cognitive capacities of the philosophers undertaking the analysis. We take ourselves to be analyzing the ordinary concept of knowledge. So, it is important to know whether we are capable of holding on to the ordinary concept and the intuitions that go with it even as we acquire other philosophical commitments. If philosophical study is subtly warping our epistemic intuitions, our confidence in our ability to analyze the ordinary concept of knowledge may be misplaced.
One of the best arguments for naturalized epistemology is encapsulated in this paragraph from Quine's seminal essay, Epistemology Naturalized:
The old epistemology aspired to contain, in a sense, natural science; it would construct its somehow from sense data. Epistemology in its new setting, conversely, is contained in natural science, as a chapter of psychology. But the old containment remains valid, too, in its way. We are studying how the human subject of our study posits bodies and projects his physicis from his data, and we appreciate that our position in the world is just like his. Our very epistemological enterprise, therefore, and the psychology wherein it is a component chapter, and the whole of natural science wherein psychology is a component book—all of this is our own construction or projection from simulations like those we were meting out to our epistemological subject. Thus there is reciprocal containment, though containment in different senses: epistemology in natural science and natural science in epistemology.—W.V.O. Quine, Epistemology Naturalized, pg 25.
In this passage Quine explains why it is important to study the cognitive psychology of individual human subjects. As an empiricist, Quine holds that all evidence is sensory evidence. Scientists are human beings who grapple with the same limitations as our ordinary subject. They are attempting to formulate much more complicated theories from more unusual kinds of data, but ultimately their task is the same as that of every human being trying to make sense of the world.
Quine reminds us that epistemologists are also human investigators who must also compile and analyze sensory experience to understand knowledge as a natural phenomenon. According to Quine, we acquire concepts of like knowledge and justification by extrapolation from observations of the applications of these terms in everyday life. If so, it is an important empirical question whether members of a linguistic community end up with the same or similar concepts despite having slightly different experiences.
Steven Stich summarizes a lot of important empirical work on epistemic intuitions in this paper. Therein, he cites evidence for diversity in basic epistemic intuitions in the general population (including interesting variations by ethnicity, socioeconomic status, etc.) Interestingly, the incidence of externalism is much higher among some populations than others.
If Stich's claims are borne out, they have important implications for how we ought to do epistemology. One of Stich's key concerns is that there might be different but equally defensible sets of basic intuitions about justification. The internalism/externalism debate often proceeds as if the task were to come up with the definitive analysis of a shared concept of knowledge. The discovery of diverse but stable intuitions would shift the terms of debate. The debate might shift to choice of intuitions. Here again, empirical data might be directly relevant. It might matter how people acquire these basic intuitions. Maybe some arise by more defensible means than others.
There are interesting epistemological and empirical issues involved in the measurement of people's intuitions. How do we know whether two people have the same intuition? Can we measure changes in intuitions? If intuitions do change, how do we ascribe reasons and causes for the shift?
These data are important to the normative aspects of epistemology. One familiar criticism of naturalized epistemology is that it leaves out the evaluative dimension. Allegedly, traditional epistemology retains its prescriptive force because a successful conceptual analysis would vindicate certain doxastic norms by showing them to be implicit in our very concept of knowledge. As Kitcher and Stich have argued, the next question is always why we ought to accept that particular conception of knowledge.
Traditionalists might argue that the conceptual possibility of divergent intuitions was already acknowledged long before the research bore it out. Epistemologists have been struggling with this issue from their armchairs for years. The naturalized epistemologist should reply that we can't decide the implications of these findings without further understanding of the psychological processes that generate and sustain intuitions. The diversity of intuitions might be evidence against the human mind's alleged a priori access to key concepts. Moreover, naturalized epistemologists of pragmatic bent might argue that the "choice of intuitions" problem should be resolved by appeal to pragmatic investigation of the effects of these different intuitions. If internalism or externalism were shown to confer an advantage in achieving certain cognitive ends, this might be an argument for switching sides or broadening one's account of justification to include more than one sense.
From cognitive psychology we learn more about how human beings, ourselves included, learn and reason. By observing scientific practice and reflecting on scientific methodology, we observe the expansion of empirical knowledge. When we reflect on questions of justification, we must do so in light of our understanding of ourselves as limited, embodied beings. The validity of our methods depends on our ability to rule out or compensate for certain limitations or distortions imposed by our own cognitive makeup.
Edit: Thanks to Thomas Nadelhoffer of Experimental Philosophy for the kind linkage.
Also, EP blogger Jacob Weinberg has posted a link to his new paper about calibrating intuitions. Check it out.