Aquinas' treatment of the mind in the Summa Theologiae begins properly with question seventy-nine, a long question with thirteen articles with the title 'On the intellectual powers'.

Before discussing the question, we need to say something about the translation of the crucial terms of the discussion. Aquinas' intellectus is fairly enough translated by the English word 'intellect': as we shall see, it is the capacity for understanding and thought, for the kind of thinking which differentiates humans from animals; the kind of thinking which finds expression especially in language, that is in the meaningful use of words and the assignment of truth-values to sentences. But English does not have a handy verb 'to intellege' to cover the various activities of the intellect, as the Latin has in intelligere. To correspond to the Latin verb one is sometimes obliged to resort to circumlocutions, rendering actu intelligere, for example, as 'exercise intellectual activity'. An alternative would be to use the English word 'understanding', in what is now a rather old-fashioned sense, to correspond to the name of the faculty, intellect us, and to use the verb 'understand' to correspond to the verb intelligere. In favour of this is the fact that the English word 'understand' can be used very widely to report, at one extreme, profound grasp of scientific theory ('only seven people have ever really understood special relativity') and, at the other, possession of fragments of gossip ('I understand there is to be a Cabinet reshuffle before autumn'). But 'understand' is, on balance, an unsatisfactory translation for intelligere because it always suggests something dispositional rather than episodic, an ability rather than the exercise of the ability; whereas intelligere covers both latent understanding and current conscious thought. When Aquinas has occasion to distinguish the two he

often uses actu intelligere for the second: in such cases the expression is often better translated 'think' than 'understand'.