Abstract: Augustine invented expressionist semiotics, the theory that words and other bodily things are external signs that give expression to what lies within the soul. This theory of signs is quite different from Greek philosophical semiotics, which is a theory of empirical inference, not a theory of language or expression. Augustine's semiotics is rooted in his Platonism, which allows no external or sensible thing to have causal power over the inner realm of the soul. Consequently, Augustine thinks we learn nothing from words, not even from Scripture. Faith, for Augustine, means believing in the authority of external teachers or witnesses, which is useful so long as we cannot yet see for ourselves in the light of the inner teacher, which is Christ, the Wisdom of God. Like words, sacramental signs are inherently powerless, and cannot convey to us any inner thing. Hence, in contrast to medieval theology, Augustine has no place for sacraments as efficacious means of conferring grace and does not attribute life-giving power to the flesh of Christ.

Keywords: Augustine, Platonism, semiotics, expression, signs, words, grace, inner, external, soul