Kris Hartung, one of the Examiners over at Examiner.com, tells us that claims to objective knowledge must “result in either circularity or a simple act of pragmatism.” Presumably the only claim to objective knowledge that passes muster is the one about how such claims are logically impermissible.
Well, nonsense, I claim. The validity of reason is based on the law of causality, an implication of the law of identity. Contra Hume or anyone who equates fantasy with the real world, no pumpkin “might” instantly turn into a rabbit, even if an animator can conceive this. The pumpkin has no rabbitish potentiality that could enable the transmogrification. Nor need we worry that our understanding of this matter might one day be falsified and overturned.
Once a human being has been around a while, observed a few things and learned to conceptualize, he can grasp that anything whatever, as yet observed or not, can be only what it is, cannot be both itself and something else at the same time and in the same respect. One doesn’t have to prove this principle; it is self-evident and inescapable.
Kartung says that we can’t be absolutely sure that Kepler’s second law of planetary motion, about the area swept out by planets as they orbit the sun, will hold in the future; he says that it’s merely probable in some degree. On the skeptical view, one may also as well assert that planets will only “probably,” not necessarily, keep revolving around their suns (absent any countervailing factor), whether in accordance with Keplerian formula or not. But masses are masses. Gravity, an attribute of masses, is not going to fade out without cause. There’s no need to be mousy about this. Accepting the law of identity, we can accept causality and its implications for our lives confidently, not as a matter of tentative, fearful, self-contradictory, thumbsucking “pragmatism.”
Of course, our understanding of the world does not come to us in prepackaged lumps of final incontrovertible truths. Many things are indeed uncertain—not because the law of identity might implode at any moment, but because we still have work to do in finding out the identity of something. Many scientific questions may be unsettled, or wrongly settled. But no inquiry, including corrective inquiry, is even possible without at least tacit acceptance of the law of identity and hence the law of causality. You can’t investigate a something without accepting that the something is there to be investigated.
The fact that “thinkers of the past” or of today, or anybody, can be wrong—the trump card Hartung flings at the reader at the close of his piece—is no evidence against the regularity of nature or the possibility of objective knowledge of it. Yes, human beings are fallible (and we can be absolutely certain of this). It is because we human beings are fallible that we need and should rely on scrupulously rational methods of inquiry, and should be willing to modify or relinquish old understandings when new data or a more illuminating and logical grasp of familiar data requires such modification or relinquishing. But whatever anybody alleges, the laws of identity and causality are not among the doctrines that ought to be given the pink slip.