But before we can begin to look for the criterion of truth, we have to ascertain that there is such a thing as truth. Now, unless one accepts that there is indeed such a thing as truth, nothing holds: remove truth, and everything collapses. Nothing can get around this: “there is no truth” cannot be taken as true since it would ipso facto refute itself. Why is it that self-refutation, inconsistency in logical terms, matters? Because an inconsistent thesis, that is to say, a thesis that bears its refutation within itself, has no real persuasive power: to expect others to believe in it would be to expect them to take it as true, hence to expect them not to believe in it. In that case, one would have to keep it to oneself and say: “I do not know.” That does not mean, however, that “no one else knows, either,” since that would imply that one knows that the proposition “no one else knows” is true, which would contradict the initial “I do not know.” In fact, even to say “I do not know”—in response to the question of whether one knows if there is such a thing as truth—would be inconsistent, for to say “I do not know” is to imply that I know that one thing is true and that is precisely the fact that “I do not know.” He who does not take the self-evidence of truth for granted is bound to remain silent, or else ends up contradicting himself. 

The denial of truth, therefore, or doubt about it, cannot be the starting point of any logical system of thought: to avoid inconsistency —that is, to remain logical—one has to assume that there is such a thing as truth before one presents any reasoning. This is a fundamental “dogma” without which nothing holds. It shows, moreover, that no system of thought can be without a dogma. A “dogma-free” starting point is itself a dogma, though a self contradictory one. 

It should be clear that in showing the inevitable inconsistency of the opinions that deny the notions of truth and objectivity, we are demonstrating the logical absurdity of many of the philosophical movements that have emerged since the dawn of the Age of Reason. Any system of thought that proposes an absolute principle while denying the notion of truth—hence the notion of objectivity—is condemned to self-refutation. This applies to subjectivism, in all its forms, which precisely denies the notions of truth and objectivity. The central thesis of every subjectivist opinion—various forms of the thesis that “there is no objective truth”—when applied to itself, refutes itself. Similarly, relativism carries the seed of its own negation within itself since it refutes its central thesis that “everything is relative” by this very thesis. Agnosticism, on the other hand, pretends to avoid the logical inconsistency of relativism by refraining from making a pronouncement on truth while implicitly promoting the idea that man is incapable of knowing it, that is, “I do not know” is taken as true of every man; in effect, therefore, it promotes the idea that “no one else knows, either.” An agnostic, to be logical, would have to remain silent, in which case there would be no one to propose agnosticism. The arbitrary, hence self-refuting, nature of the philosophies that proclaim the primacy of experience or feeling is clear, for their overarching principles—which are mental formulations —can be neither experienced nor felt, precisely because mental formulations do not fall within the scope of experience or feeling. For example, the thesis that “experience is the criterion of truth” means that every truth will have to be empirically verifiable. Now, this thesis itself is not empirically verifiable. Consequently, the proposed thesis is not true according to its own measure. Empiricism, therefore, refutes itself. Not unrelated to this is any ideology that seeks to base truth on the experiences and feelings of man in his subjectivity and individuality: for example, various forms of existentialism, which place great emphasis on the individual’s experiences and feelings.

Philosophy of Science in the Light of the Perennial Wisdom

Mahmoud Bina & Alireza K. Ziarani
Alireza gives a talk here

I like the idea of a true agnostic needing to remain silent. It passes the heuristic that most people proclaiming Truth are foolish, mistaken, immature, or full of shit. This blog existing is self defeating. Funny how that works.