(This post is not comp-related; it's just an attempt to crystallize something that I was thinking about today.)
Many philosophers (including me) tend to operate under the assumption that a claim has value only if it is true. This assumption is propped up by a vague worry that the only way to deny it would be to adopt an unattractive view about truth, such as nihilism, some kind of relativism, or an obscure post-modernism.
This worry is unwarranted. The problem (or at least a problem) with the assumption that a claim has value only if it is true is not that there is no such thing as truth, or that truth is not absolute, or that truth is not an important desideratum; it is that truth is too high a standard to apply across the board to all intellectual endeavors. Truth requires total precision, an absence of ambiguity, and complete fidelity to the facts. It's difficult to think of any claims outside of logic and mathematics that meet this standard.
One might admit that truth is too high a standard, but deny that it is too high an aspiration. That is: we should always aim for the truth, even if we can never reach it.
I agree that, within a particular inquiry, one should aim to be as faithful to the facts as possible, all else being equal. However--and here's the point that I want to emphasize--one should not place such a high premium on truth that one neglects interesting and important approaches to interesting and important topics on the sole grounds that those approaches to those topics will not yield claims that are true, or even very nearly true.
Consider the account of the nature of science that Kuhn presents in The Structure of Scientific Revolutions. Many critics have pointed out that many aspects of Kuhn's view are false. Take, for instance, the claim (implicitly suggested if not explicitly stated in Kuhn's account) that any sufficiently mature field of science is governed by one dominant paradigm at any given time. It would be easy to multiply examples of seemingly mature fields that contain multiple competing paradigms, and perhaps fields that don't seem to be governed by any very unified paradigms at all.
I don't claim that critics should not compare Kuhn's account of science to actual scientific practice and to point out disparities. What I do claim is that one should not be too quick to move from the claim that Kuhn's account is false in many respects to the claim that Kuhn's account is not useful or valuable for understanding science.
Kuhn gave us is a highly original way to think about science. That framework is imperfect in many ways. If we take it too seriously, it can lead us astray. But by giving us a new way to think about science, it allows us to notice things we would not otherwise have noticed and to draw connections we might not otherwise have drawn. It may be that, even though Kuhn's account is false, we're better off with it than without it.
The same could be said about any number of ambitious projects, particularly in intellectual history. Dewey's The Quest for Certainty and Collingwood's The Idea of Nature are good examples. We philosophers tend not to read such works any more, and we (at least most of us) certainly don't attempt to write them. One reason we shun such large-scale projects, I think, is that we realize that any picture we can paint with such broad strokes will inevitably misrepresent the complex, messy reality of the phenomena we wish to characterize. What we say won't be true. Moreover, counterexample-mongers will advance their careers by pointing out that what we say isn't true.
But maybe that's ok. Maybe what we say doesn't have to be true to be illuminating. Fidelity to the facts matters, but it doesn't matter so much that any significant departure from the facts completely vitiates a project; and it doesn't matter so much that we should only pursue projects for which near-perfect fidelity to the facts is an achievable goal.