What philosophers know
Consider, for example, discussions of free will. Even neuroscientists studying freedom in their labs are likely to offer confused interpretations of their results if they aren't aware of the distinction between caused and compelled, the various meanings of "could have done otherwise", or the issues about causality raised by van Inwagen's consequence argument. Parallel points apply for religious people thinking about the problem of evil or atheists challenged to explain why they aren't just agnostics. Philosophers can't show what our fundamental convictions should be, but their knowledge is essential to our ongoing intellectual engagement with these convictions.