Life and soul

From the study of change as such, in all bodies whatsoever, we pass now to the study of self-change in those bodies – plants, animals and human beings – which have an internal principium mutationis known as the anima.

Like the Greek ‘psyche’, to which it corresponds, anima has been conventionally translated into English as ’soul‘; and the modern reader's first task is to clear his or her mind of the connotations that this word has acquired in popular Christianity, and to re-establish the etymological link with the adjective ‘animate’, which still conveys both the meaning and the neutral tone of the medieval original. In other words, the ‘souls’ that concern us in the present chapter are not necessarily ‘immortal’, and are to be found in dogs and in trees as well as in human beings. Everything that has life is by definition ‘en-souled’ (a corpus habens vitam must be animatum). Everything that is ‘animate’ must be ‘animated’ by an anima of some kind.

The term anima may be correctly paraphrased as the ‘vital principle’ or the ‘first principle of life’ (primum principium vivendi), or as ‘that by which the body first lives’ (id quo primum vivit). But the simplest possible definition is ‘the substantial form of a living body’ (forma substantialis corporis viventis).

A forma substantialis, it will be remembered, is that by virtue of which a body exists or subsists in its own right (id quo est), and also that by virtue of which it possesses a certain number of characteristic properties or powers.