That, however, had never been my principal concern, for my attention was directed only to what I had written against them in the field of theology.

Later I realized that much of what they set down as first principles—both in theology and in logic—lies at the very root of the flaws in their theological discourse: for instance, their claim that quiddities are composites of attributes they call “essentials,” their attempt to restrict the routes to knowledge to the definitions and demonstrative syllogisms they list, indeed even to the very definitions by which conceptions are known, and to the forms of syllogism together with the premises they deem certain.

Some people then wished to copy what I had written at that time concerning their handling of logic, and I granted permission, for it opens a door to recognizing the truth—though the scope for refuting them could accommodate many times what I penned in that single sitting. I therefore said:

Section:
A Concise Outline of the Principles of Logic and Its Technical Terms

The logicians built their discipline upon the discussion of definition and its kinds, and of the demonstrative syllogism and its kinds. They maintain that knowledge is either conception or assent; each of these is either self-evident or theoretical. It is evident that not all knowledge is self-evident, while it is impossible that it all be theoretical, for the theoretical depends on the self-evident. Otherwise one would be caught in a prior circularity or an infinite regress with respect to causes—which here are the grounds of knowledge, namely the proofs—both of which are impossible.

Each theoretical type therefore requires a path by which it is attained: the path to attaining conception is the definition, and the path to attaining assent is the syllogism.