Augustine On Dialectic

"Dialectic is the science of arguing well. As you know, we use words when we argue. Words, you see, are either simple or complex. Simples are those which signify one thing, as when we say `man, horse, argues, runs'. You should not be surprised that `argues', though it is composed of two things {argue + s, trans.}, nevertheless is numbered among the simples; for this is clear from the definition. We said that a word was simple when it signified one thing. Thus it (argues) is covered by the definition, but it is not covered when I say `loquor' (I speak), for though this is one word, it does not have a simple meaning, since it also designates the person who speaks. Hence it is from the first subject to being either true or false, since it can be affirmed or denied. Thus, all the verbs of the first and second person, although pronounced as one word, nevertheless must be counted among the complex words, since they do not have a simple meaning. Thus, whoever says `ambulo' (I walk) makes understood both the action of walking (ambulation) and that he himself does it, and anyone who says `ambulas' (you walk) likewise signifies both the action performed and the person performing it. But when a person says `ambulat' (walking is going on), he signifies only the action of walking, whence third person verbs are always numbered among the simples and can never be affirmed or denied, except when they are verbs such that there is of necessity attached to them the signification of person by usage, as when we say `pluit' (it rains) or `ninguit' (it snows), even when we do not add what rains or snows; since it (the subject) is understood, they cannot be put under the simples." - St Augustine, de dialectica i, J. Marchand [Trans].