Atomism and Perception: A Reply to Barnes

According to Barnes, however, I am stuck in the unhopeful position of not being able to trust my senses, and therefore unqualified to expound on the structure of reality. My poor perception cannot arrive at the answer to these matters. But alas, if perception is illusory, why embrace anything at all? This is a logical extension of Barnes’ obstruction that, “If perception is illusory, why embrace atomism?” It is my point that if Barnes’ obstruction is warranted for atomism, it is also warranted for any alternative to atomism. Why embrace anything, for that matter? Having been reduced to an absurdity, why embrace Barnes’ own argument?

This is, after all, Barnes’ Waterloo. He assumes one can only pass a posteriori judgments on the nature of matter. I also have my rational mind to work with, the atomist rightfully contends, where perception does not impede my judgment. In fact, if my perception is so flawed, then I might as well embrace my a priori judgments—and if the a priori judgments lead me to an atomic theory of the universe, then I should actually embrace it.

Atomism, of course, is either true or untrue. Moreover, to embrace a theory one must to some extent be convinced that it is valid. At the very least, I am prepared to embrace a theory on the basis of pragmatism. That is, if I believe embracing atomism is useful in explaining other phenomena, for example, if I work in the pharmaceutical industry or perchance am a particle physicist at Fermilab, and for certain reasons need to suppose that matter is indestructible at some level, I will. Atomism, then, can serve as a means to practical ends. But, pragmatism aside, how might I be convinced that to some extent atomism actually is valid?

Just as I have stated that a posteriori cannot solve for atomism, it may be objected that a priori cannot solve this problem either. Perhaps a more thorough argument would lead us to the world W’ in which matter is infinitely divisible. The atomism of W, after all, seems to have been superceded by W’ in the realm of the inductive sciences. At this level of argument I am prepared rather to agree with the objector. An a priori argument would seem to suggest that W’ is the actual world in which we live, although this is hardly conclusive. But Barnes does not seem to be concerned whether atomism is true as a scientific theory, and for that matter, neither am I. Still, we want to answer the question of why we should embrace atomism.

Perhaps it should not be embraced because atomism is thought to presuppose the validity of sense-perception and “to gain support from its capacity to explain the phenomena of perception,” as Barnes puts it. But in what sense, does atomism presuppose the validity of sense-perception? That reality exists, as I have shown, does not presuppose sense-perception; Descartes’ brain in a vat is able to determine whether reality exists. That sense-perception as a phenomenon exists, it is explained by atomism only insofar as atomism is true and explains all phenomena. That sense-perception especially is explained by atomism is a non-unique argument. Moreover, to emphasize my point, if atomism is true, a posteriori judgments are misleading. So why ought an atomist be required to presuppose the validity of something a posteriori to prove an a priori construct?

That atomism may or may not be true is an open question. That atomism may be defended by Barnes’ assumptions has been shown to be true through my own argument. Since Barnes’ believes that ordinary, rational people ought to believe his arguments, and since his arguments do not stand, then this entails that ordinary, rational people ought to rather believe atomism provides a rational alternative to the idea that matter must be infinitely divisible. Of course there may be other reasons for supposing that atomism ought to be embraced, in the scientific, linguistic, philosophic communities or elsewhere. There may be a priori arguments in favor of the necessary truth of atomism, although it is certainly difficult to see what the reasons might be. Hence my tentative conclusion: if Barnes’ skepticism about the atomists’ view on perception is rational, so is Democritus’ skepticism about the possibility of human knowledge.