Suppose we can identify at least some of the kinds of evidence thatsupport philosophical claims. Matters do not end there because we wouldstill need to evaluate the kinds of evidence. We would need to know justhow good those kinds of evidence are. At one time people thought thatthe state of chicken entrails provided evidence about what lay ahead. Thatwas clearly not the best method of predicting the future. But is there anyreason why we should suppose that today’s philosophers are any less inerror? This is not an idle concern. Some philosophers have thought thatphilosophy’s track record of discovering truths, as opposed to promulgating falsehoods, is no better than the track record of examining chickenentrails as a guide to the future.2 So if one key issue concerns what kindsof evidence support philosophical claims, a second key issue concernshow reliable those claims are—how likely are they to lead to true claimsas opposed to false ones.The fact that philosophers do not have laboratories packed with testing and measuring equipment has perhaps encouraged the belief thatthey do not need them, and, more generally, that philosophers do notneed any kind of empirical information in developing and defendingtheir views. The idea is that if philosophers do not rely on empirical data,they must rely on non-empirical data. These data would have to be dataof a special kind accessible by intellectual reflection in an armchair. Andif philosophers’ hypotheses are tested by non-empirical data, then thesehypotheses themselves will not be empirical hypotheses. They will notbe hypotheses about the empirical world, but hypotheses about how wethink about the empirical world. They are hypotheses about our representations of things. Philosophy then becomes an enquiry into the nature ofour representations or concepts of things. This encapsulates the idea ofphilosophy as conceptual analysis, of philosophical hypotheses as claimsabout what are concepts are like and how they are necessarily related toone another. This conception of philosophy continues to be influential.The line of argument in the preceding paragraph, however, can beresisted. Even if philosophers do not have laboratories, and do not runempirical experiments, it does not follow that empirical data are irrelevant to philosophical theories. Such data might even be required bythose theories. After all, many theoretical physicists themselves do nothave laboratories and do not run empirical experiments. Neverthelessthey depend upon the laboratory and field results of experimental physicists to get evidence for their theories