LOGIC AND LANGUAGE all, words like ‘of ’ cannot be ostensively deWned; and, more fundamentally, the gesture of pointing, no less than the utterance of a word, is only a sign, not the reality signiWed (DMg 5–6) Augustine responds to these objections that there are some words, like ‘walk’, ‘eat’, and ‘stand’, which can be explained by producing an instance of the very thing signiWed: I ostensively deWne ‘walk’ by walking But suppose I am already walking when someone asks me what ‘walk’ means: how I deWne it? I suppose I walk a little faster, says Adeodatus But this shows that even in this favoured case ostensive deWnition is incurably ambiguous: how I know whether the meaning that is oVered is that of ‘walk’ or of ‘hurry’? Eventually Augustine concludes from the failure of ostensive learning that the meaning of words is not something that is taught by any human teacher, but by a teacher within us whose home is in heaven (DMg 14 46) This is a Christian version, in the special case of language learning, of Plato’s thesis in the Meno that all learning is really recollection On the way to this conclusion, however, Augustine discusses a number of important issues in philosophy of language First, he classiWes signs in a rudimentary semiotic All words are signs, but not all signs are words: for instance, there are letters and gestures All names are words, but not all words are names: besides words like ‘if ’ and ‘of ’ there are pronouns, which stand in for nouns, and verbs, that is to say, words with tenses (DMg 9, 13) It is important to keep in mind the distinction between a sign and what it signiWes (what Augustine calls its ‘signiWcable’) No one is likely to confuse a stone with a word for a stone: but some words are words for words, and here there is a real danger of confusion between sign and signiWcable In modern English we minimize the risk of such confusion by employing quotation marks Adeodatus is human, and there are two syllables in ‘human’ In antique Latin, with no quotation marks, there is no such clear distinction between the normal case when we use the word as a predicate, and the special case where we use it in order to mention itself Adeodatus has to be on his guard to avoid the trap set by his father: you are not composed of two syllables, therefore, you are not human (DMg 22) Augustine devotes several pages to explaining that while, at one level, not all words are names, at another level every word is a name since 117