In the concluding paragraph (quoted here) of Glymour's controversial manifesto, we find three criteria to keep philosophy departments around: 1. Grant-making ability; 2. Being cited and useful outside philosophy; 3. Good undergraduate teaching. All three are sensible reasons to give philosophers some "shelter" in a university (it's not clear they are also good reasons for a distinct department). In his piece, Glymour focuses (with a nod to Michael Friedman) on the second reason; he praises those philosophers that are "outsiders to the science of the day, people who will take up questions that may have been made invisible to scientists because of disciplinary blinkers." Glymour presupposes that at any given moment science is not necessarily, optimally truth-tracking--a topic close to my heart. That is, one task for philosophy is to be critical of present science (but not the scientific ideal) in an informed and constructive fashion. Despite Abe Stone's protests so far so good. But from here Glymour's argument slides.
One not-so-innocent (even quaint) premise in Glymour's manifesto is this: "Philosophy, while it can be combined with empirical work, is an a priori effort, and the tools of the a priori are opinion, logic, mathematics and the theory and practice of computation." Glymour seems to think that it is self-evident that philosophy is an a priori enterprise (which following upon my remarks, he thinks is being split between poorly trained folk that embrace intuition, and rarer, better trained folk that use formal tools). Glymour adds that "to use them [the tools of the a priori--ES], Friedman’s vision requires as well a knowledge of the sciences." So, according to Glymour good philosophy is, in part, an a priori discipline that preferably focuses on formal techniques and, in part, a scientifically literate application of these techniques to improve the sciences. All of this, presumably in the name of truth. [I have grown increasingly skeptical about the way most supposedly scientific philosophers think about what it is to have "knowledge of the sciences!" But let's leave these concerns aside.]
But Glymour's manifesto provides a hint that he realizes his argument has gone seriously off the rails: "(My apologies to the many contributors my brief summary omits, especially to those using philosophical background to write insightfully and importantly about public policy.)" Why is this significant? For, while truth is certainly not irrelevant to writing "insightfully and importantly" about public policy, it is often other values (justice, humanity, equity, etc) that presumably make the difference here. Glymour realizes this, too, because he had already singled out for praise "liberal ambitions" and "politics." But the way Glymour has construed philosophy (as an a priori enterprise) leaves it thoroughly mysterious why truth and Liberal values/politics necessarily coincide. Now, here I am not ruling out, in advance, that no such a priori connection can be given. But it seems reasonably likely that all kinds of a posteriori facts are going to motivate and even justify the commitment to Liberal values.
Glymour's way of thinking about the nature of philosophy leaves that supremely important task -- how to think about values that ought to guide philosophic contributions to public policy -- as un-philosophical, or hidden somewhere in the axioms of formal apparatus. Moreover, it leaves no room for the thought that the proper political application of philosophic techniques is itself crucial to philosophy. And this flaw is related to why, as Abe Stone noted, he mistakenly thinks that "Carnap’s “principle of tolerance” was an invitation to triviality." That is to say, Gleymour has no resources to even to begin to argue for what is at stake in speaking philosophically in a polity. (Or, as Mark Lance noted, to think clearly and honestly about how the polity can corrupt philosophy.) When philosophers don't know how to think about philosophy's relationship to politics this is a recipe for disaster (cf. LSE Philosophy and Ghaddafi), or (with a nod to Aristophanes) wry comedy.