Skepticism

Augustine’s earliest surviving work, his Contra academicos (Against the Academicians), is a response to skepticism. In young adulthood Augustine had been a Manichean ‘‘hearer,’’ or disciple. But, after nine years in that role, he became disenchanted with Manicheanism. About the time he left Carthage for Rome, he found himself attracted to the skeptical view of the ‘‘Academics,’’ that is, the followers of Arcesilaus and the New Academy, who held that “everything was a matter of doubt and that an understanding of the truth lies beyond human capacity’’ (Confessions, 5.10.19). In the Contra academicos Augustine discusses the criterion for knowledge put forward by Zeno of Citium, according to which something can be known just in case it cannot even seem to be false. Augustine proposes a dilemma. Either Zeno’s criterion can be known to be true, in which case it is false, or else it cannot be known to be true, in which case we have inadequate reason to accept it.

Augustine goes on to offer knowledge claims of his own that he dares the skeptic to reject, among them, certain logical truths, certain mathematical truths, and certain reports of immediate experience (e. g., ‘‘That tastes pleasant to me’’). Especially interesting is his claim to know that the world exists. To the skeptic’s taunt that he might be dreaming, Augustine responds that he will call ‘‘the world’’ whatever appears to surround him. In this way he introduces the idea of a phenomenal world, knowledge of which, he maintains, is impervious to skepticism.

No doubt Augustine’s most famous response to skepticism comes much later, in Book 15 of his On the Trinity and in Book 11 of his City of God. Here is the latter passage:

>  In respect of these truths I have no fear of the arguments of the Academics. They say, 'What if you are mistaken?' If I am mistaken, I am [Si fallor, sum.] Whoever does not exist cannot be mistaken; therefore I exist, if I am mistaken. Because, then, I exist if I am mistaken, how am I mistaken in thinking that I exist, when it is certain to me that I am if I am mistaken (11.26).

The anticipation of Descartes’ cogito, ergo sum is clear.