The Philosophy of Philosophy * By Timothy Williamson * BLACKWELL, 2007. x + 332 pp. 15.99 paper: Summary

The book is primarily an essay on the epistemology of the sort of armchair knowledge that we can hope to achieve in philosophy. The possibility of such knowledge is not to be explained by reinterpreting philosophical questions as questions about words or concepts. Although there are philosophical questions about words and concepts, most philosophical questions are not about words or concepts: they are, just as they seem to be, about the things, many of them independent of us, to which the words or concepts refer. Nor is our linguistic or conceptual competence the basis for our philosophical knowledge; such competence merely enables us to ask the questions, without guiding us to the answers. Notions of analyticity do no explanatory work in epistemology. Nevertheless, a valuable residue of the linguistic turn is an enhanced ability to determine whether arguments are valid. For whether an argument is truth-preserving depends on the joint truth-conditional semantic structure of its premises and conclusion, which we can now investigate more rigorously and reliably. Philosophy is much less different from other disciplines than many philosophers like to pretend. Armchair knowledge involves no special faculty of intuition. We achieve it in philosophy by unusually painstaking applications of cognitive faculties whose main role is to provide quite ordinary sorts of knowledge. The epistemology of metaphysical modality provides a case study. Metaphysical possibility and necessity are equivalent to special cases of counterfactual conditionals. The cognitive capacities that enable us to evaluate ordinary contingent counterfactual conditionals also enable us, as an accidental by-product, to evaluate attributions of metaphysical modalities. Notable in this respect is our ability to evaluate offline in the imagination, under counterfactual suppositions, propositions that we can evaluate online in perception. Both abilities involve skills in applying concepts that go well beyond mere possession of the concepts or linguistic competence. The offline employment of conceptual skills is the basis of armchair knowledge in philosophy. Since experience plays a significant role in honing such skills, even when it is not providing us with relevant evidence, the distinction between a priori and a posteriori knowledge goes much less deep than is often thought. This account can be applied in particular to philosophical thought experiments, which are typically valid modal arguments. The imagination plays its usual role in them when we evaluate the modal premises. Intellectually respectable philosophy is an evidence-based discipline. As elsewhere in epistemology, there has been a tendency to mischaracterize the nature of the evidence, psychologizing it under sceptical pressure in a futile attempt to make it dialectically neutral. This has in turn tended to make the evidence largely irrelevant to the mainly non-psychological questions that philosophers are asking. Talk of intuitions is an artefact of this mistaken approach. Even characterizations of philosophical method in terms of reflective equilibrium depend on unwarranted internalist preconceptions in epistemology. Our evidence in philosophy is whatever we happen to know; controversy as to what facts are part of our evidence is inevitable. Still, we can take mild solace from a knowledge-maximizing principle of charity that constrains the determination of content.