Some philosophers would claim that I am attacking a straw man. They might say that philosophy has an admixture of empirical testing, for example in the new sub-discipline of ‘experimental philosophy’. I would reply that such a claim is in danger of falling between two stools. If philosophy has an element of empirical investigation, should it not be judged by the standards of science? If (as most philosophers claim) philosophy is distinct from science, then by what standards is the former to be judged? Philosophers do sometimes refer to empirical findings from physics, psychology or sociology; but they either do straightforward science with the data, or (more often) merely use it to set the context for a philosophical ‘problem’ (e.g. various experiments in psychology are used to illustrate the mind-body problem). Some philosophers may argue that scientists are also engaged in theoretical reflection, so why not philosophers? Yes, but scientists (unlike philosophers) test their theories experimentally.
When doing philosophy rather than science, what philosophers do largely fails to show that they are not essentially engaged in a priori or ‘armchair’ theorising (by the way, ‘experimental philosophy’ is not philosophy, but psychology applied to issues in philosophy). The criteria philosophers rely on are basically those of logic, grammar, and a priori or ‘armchair’ intuitions ‘tested’ in thought-experiments. Unfortunately, these criteria are insufficient to underwrite the semantic meaningfulness of philosophical discourse. Most philosophers agree that logical and grammatical consistency alone does not entail semantic consistency. There are a host of problems with the epistemic status of a priori intuitions; particularly as filtered through multiple thought-experiments in the course of a philosophical discussion. There is simply too much arbitrariness in the configuration and interpretation of thought-experiments to allow for a straightforward analogy with ‘real world’ experiments.
It doesn’t matter much if a philosopher is also an expert in another discipline. There are many such philosophers (some with double doctorates, in philosophy and something else). Unfortunately, their colleagues outside philosophy generally don’t pay much attention to them anyway. Because even multi-disciplinary philosophers still insist on studying philosophical problems. For example, a philosopher who is also a clinical psychologist may be interested in the ‘hard problem’ of consciousness or in personal identity, but such issues are not relevant to clinical psychology (psychoanalysts might be more interested in such problems; but psychoanalysis is methodologically similar to philosophy, in being largely discursive). When a philosopher’s views are of interest to say, a physicist, it is usually because the former is doing physics and not philosophy.
Why is this the case? I don’t think it’s because disciplines outside philosophy are ‘missing out’ and need to re-orientate their focus on philosophical issues in their subject-domains. Unfortunately, when a philosopher claims there are ‘philosophical problems’ in a subject outside philosophy, it’s usually because he brought the dilemmas with him. By and large, the problems do not have their source in subject-matters outside philosophy; but are the result of the philosophical method itself (in particular, its purely discursive approach; which engenders the sort of misunderstandings that fuel philosophical scepticism). That is why such problems are largely irrelevant to disciplines outside philosophy which do not share the same method (but are relevant to disciplines that do; such as literary, social or political theory, psychoanalysis and speculative theology). Having said that, it is true that specialisation in any subject brings a certain myopia, which could be mitigated by cross-disciplinary fertilization. But based on its track-record, philosophy has less to contribute and much more to benefit from that cross-fertilization, if philosophers can drop their aversion to empirical investigation.
Some may object that based on what I’ve said, I’m just another philosopher with a philosophical theory of my own; inspired by the ‘ordinary language’ school, represented by the likes of Gilbert Ryle and (later) Wittgenstein. I plead guilty to taking a broadly ‘ordinary language’ approach, but I’m not sure if one could call it ‘philosophy’ without misrepresenting philosophy in its characteristic form. After all, the ‘Wittgensteinean’ scepticism I espouse is one of the least popular versions of Wittgenstein in academic philosophy. It is the Wittgenstein that Paul Horwich refers to when he writes “the real cause of Wittgenstein’s unpopularity within departments of philosophy [is] his thoroughgoing rejection of the subject as traditionally and currently practiced; his insistence that it can’t give us the kind of knowledge generally regarded as its raison d’être”. I don’t think Wittgenstein is generally unpopular in philosophy departments, but the Wittgenstein Horwich is talking about certainly is.
Am I advocating ‘ordinary’ language-use as the arbiter of correct language-use in every case? The claim begs a definition of ‘ordinary language’, and given the inherent vagueness of most expressions, any proposed definition is likely to succumb to ‘death by a thousand qualifications’. In the absence of a definitive account of ‘ordinary language’, the strongest case that can be made for the ordinary language approach is a negative one; that the innovations in language-use introduced by philosophy are generally not an improvement on the original (even if the original is flawed, as everyday language-use often is; and is usually improved by a more subtle and nuanced use of language in context, rather than philosophical theory-building).