Descartes’ magical motto, larvatus prodeo, resonates with reason of classical antiquity. Eubulides of Megara, the contemporary opponent of Aristotle, and very likely the most accomplished inventor of puzzles in the history of logic, bequeathed to him the philosophical concept of the larvatus: Though I know my father, though he is the masked man, I still may fail to know the masked man, I still may fail to know my father as the masked man. Their schools disagreed on the way of solving this paradox. Both the peripatetics and the Megarians understood that all knowledge referred to universals. But the former insisted further that such universals were both physically and logically inseparable from the concrete particulars that exemplified them. By contrast, the latter posited an unbridgeable chasm between the real thing and its ideal representation. Eubulides pointed out that the true object of my knowledge is my father’s representation, or his eidos. In so representing, the eidos enjoys no physical link with the material presence of its representandum, the object being represented. Thus it it need not manifest itself coevally and contemporaneously with the representandum. Aristotle maintained that all corporeal presentation necessarily coincides with cognitive representation by every universal exemplified in the representandum so presented. For him, therefore, the failure of my father’s palpable presence to guarantee my recognition of his person, was an acute embarrassment.
All arguments such as the following depend upon accident. ‘Do you know what I am going to ask you?’ ‘Do you know the man who is approaching?’, or ‘the man in the mask?’ ‘Is the statue your work of art?’ or ‘Is the dog your father?’ ‘Is the product of a small number with a small number a small number?’ For it is evident in all these cases that there is no necessity for what is true of the accident to be true of the object as well. For only to things that are indistinguishable and one in substance does it seem that all the same attributes belong; whereas in the case of a good thing, to be good is not the same as to be going to be the subject of a question; nor in the case of a man approaching, or wearing a mask, is to be approaching the same thing as to be Coriscus, so that if I know Coriscus, but do not know the man who is approaching, it still isn't the case that I both know and do not know the same man; nor, again, if this is mine and is also the work of art, is it therefore my work of art, but my property or thing or something else. The solution is the same in the other cases as well. ― Aristotle, Sophistical Refutations, 179a32--179b6, Translated by W.A. Pickard-Cambridge
William Blake’s Life Mask
As this text attests, Aristotle has a ready answer to the challenge of Eubulides. His starting point is that all the same attributes are predicable only of things that are indistinguishable and coincide in their substance. Hence not all of what is true of the accident is necessarily true of the object that bears it. Consequently, wearing a mask, or more generally, presenting any particular appearance, or more generally yet, happening to be a certain way, is but an accident of the man you know. But your knowledge is predicable of him as he is in and of himself. Although the masked man and your father are one in substance, their presentations can be distinguished on the basis of the disguise only accidentally entering into the former. (This is spelled out in Aristotle’s Posterior Analytics I.4-6.) Thus to know a thing is to know its essence and its primary substance, which taken together comprise its formal cause or eidos. Nothing in this account implies or even supports the notion that an object of knowledge can have more than one essence. The troublesome part is to identify its substance and hence to demonstrate, on independent grounds, that a mode of its presentation such as the disguise caused by wearing a mask is not in any sense its essential property, but a mere matter of its happening to be in a certain way. This trouble does not arise in taking the story of the masked man as supporting the premiss shared by the Platonists and the Megarians, postulating radical discontinuity between the material objects of perception and the corresponding abstract objects of cognition. This line of argument was developed by the Stoics and subsequently advocated by Gottlob Frege and Alonzo Church.
Francis Bacon, Study for a Portrait, after the Life Mask of William Blake, 1955