Contra Eunomium is mainly a work on the philosophy of language. The impact history of Gregory’s philosophy of language, i.e. the famous OratioXII, which only in Jaeger’s edition obtained its rightful place as OratioII, is treated in chapter I. It reaches as far as to the age of enlightenment, where the same question about the origin of language is kindled. The argument between Gregory and Eunomius is concerned with the role and meaning of epinoia, i.e. human consciousness. Eunomius regards it as a matter of contempt, Gregory as one of high appreciation. The function of epinoia in Eunomius’ view is similar to an accidental and blind natural process, whereas Gregory regards it as the expression of God-given freedom, so that even the plurality of languages appears in a favourable light. Eunomius’ doctrine has its historical background in Epicurean philosophy, whereas Gregory draws on Stoic philosophy of language.
However, speaking reason (epinoia) is criticized by Gregory at the same time as merely finite knowledge, which in the shape of curiosity (polypragmosyne) tries to investigate everything, the metaphysical content as well as the objects of this world. Gregory holds against this his thesis of the impossibility of essential knowledge.