Many philosophers have a nasty habit that is best thought of as a kind of illness. Maybe some therapy would help.
It isn't new. You can see it at least as far back as der Wiener Kreis, in the work of Carnap, sometimes Russell and Frege, even Wittgenstein. Dennett and the Churchlands exhibit it in philosophy of mind, and any number of ethicists seem to be suffering from it as they read studies in neuroscience and psychology and evolutionary biology.
A lot of us probably catch it in graduate school where it attaches either to a sense of inadequacy or admiration for people practicing other real disciplines. Its hold is strengthened in those conversations where social acquaintances tell us they can't figure out why anyone would be paid to shovel such meaningless bullshit and those moments when students ask us when they will ever use what we are talking about.
Its symptoms are such an overwhelming deference to scientists that one soon loses any sense of what exactly philosophy is supposed to be, as well as an inability to see that philosophy can ever do anything—has done anything in the two-and-a-half millennia it's been knocking around—except clear up a few minor confusions in the hallways of the people who really understand the universe and its inhabitants, the scientists.
Ultimately, it leads to a kind of hard-on for science that the infected philosopher is no longer able to see any value that philosophy and its tools and methods and questions might offer, not least because she has given up the idea of value to science.
For example, here a philosopher decides that we cannot know whether literature has any value because the psychologists haven't done enough experiments yet, ignoring his own realization that literature might just be too complex to study by means of a set of laboratory experiments, and further ignoring that he has said nothing—as several commenters noted—about what makes literature good, or what moral improvement might be like, or whether we could even analyze morality by means of psychological experiments. He's too much in thrall of psychology to see that he has decided not to do philosophy or even be critical about the methods of the social sciences or question whether the right sorts of questions are being asked.
Of course, it must be sad to be engaged in a discipline that you think is no more than the handmaid of all the other—legitimate?—ones, but that's only half the problem. When students see this and when administrators see it, is it any wonder at all that philosophy gets shunted aside and cut with all the other humanities? When you give up on your own discipline, you shouldn't be amazed when others do as well.