Michael Jacovides

The intelligibility of our artifacts suggests to many seventeenth century thinkers that nature works along analogous lines, that the same principles that explain the operations of artifacts explain the operations of natural bodies.1 We may call this belief ‘corpuscularianism’ when conjoined with the premise that the details of the analogy depend upon the sub-microscopic textures of ordinary bodies and upon the rapidly moving, imperceptibly tiny corpuscles that surround these bodies.2 Locke’s sympathy for corpuscularianism comes out clearly where he describes the implications of our inability to perceive the sub-microscopic world. If we could, he conjectures, various perplexities would be unknotted. We would solve mysteries of pharmacology, since did we know the Mechanical affections of the Particles of Rhubarb, Hemlock, Opium, and a Man, as a Watchmaker does those of a Watch, whereby it performs its Operations, and of a File which by rubbing on them will alter the Figure of any of the Wheels, we should be able to tell before Hand, that Rhubarb will purge, Hemlock kill, and Opium make a man sleep; as well as a Watch-maker can, that a little piece of Paper, laid on the Balance, will keep the Watch from going, till it be removed; or that some small part of it, being rubb’d by a file, the Machin would quite lose its Motion, and the Watch go no more3 (4.3.25).

Berkeley’s capacity to conceive of mind-independent bodies was corrupted by his theory of representation. He thought that representation of things outside the mind depended on resemblance. Since ideas can resemble nothing than ideas, and all ideas are mind dependent, he concluded that we couldn’t form ideas of mind-independent bodies. More generally, he thought that we had no inner resembling proxies for mind-independent bodies, and so we couldn’t even form a notion of such things. Because conception is a suggestible faculty, Berkeley’s arguments actually made it the case that he himself couldn’t conceive of mind-independent bodies.

Seth Pringle-Pattison (233n1) observed that Locke “teaches a twofold mystery—in the first place, of the essence (‘for the powers or qualities that are observable by us are not the real essence of that substance, but depend upon it or flow from it’), and in the second place, of the substance itself (‘Besides, a man has no idea of substance in general, nor knows what substance is in itself.’ Bk. II.31.13).” In this paper, I’ll explain the relation between the two mysteries. Our Rosetta Stone is Locke’s argument that we understand body and spirit equally well since we are ignorant of their underlying substances but we “have distinct clear Ideas of two primary Qualities, or Properties” (2.23.30) of each. I’ll show that he is working with a restricted notion of primary quality in this passage, but one that demonstrably falls under the kind defined in his chapter on primary and secondary qualities. According to Locke, the fundamental primary qualities of bodies flow from corporeal substances and the determinations of these fundamental qualities constitute real essences. Locke’s discussion can’t be understood without understanding the relevant scholastic background. In the first half of my paper, I’ll explain his argument as an idiosyncratic application of doctrines he learned and taught at Oxford. In the second half, I’ll use lessons from my interpretation of the argument to explain the relation that Locke believes obtains between a substance and its fundamental primary qualities, and then I’ll build upon that explanation to elucidate his general account (insofar as he has a general account) of the inherence of qualities in corporeal substances