History of Western Philosophy - Bertrand Russell [266]
Duns Scotus was a moderate realist. He believed in free will and had leanings towards Pelagianism. He held that being is no different from essence. He was mainly interested in evidence, i.e. the kinds of things that can be known without proof. Of these there are three kinds: (1) principles known by themselves, (2) things known by experience, (3) our own actions. But without divine illumination we can know nothing.
Most Franciscans followed Duns Scotus rather than Aquinas.
Duns Scotus held that, since there is no difference between being and essence, the 'principle of individuation'—i.e. that which makes one thing not identical with another—must be form, not matter. The 'principle of individuation' was one of the important problems of the scholastic philosophy. In various forms, it has remained a problem to the present day. Without reference to any particular author, we may perhaps state the problem as follows.
Among the properties of individual things, some are essential, others accidental; the accidental properties of a thing are those it can lose without losing its identity—such as wearing a hat, if you are a man. The question now arises: given two individual things belonging to the same species, do they always differ in essence, or is it possible for the essence to be exactly the same in both? St Thomas holds the latter view as regards material substances, the former as regards those that are immaterial. Duns Scotus holds that there are always differences of essence between two different individual things. The view of St Thomas depends upon the theory that pure matter consists of undifferentiated parts, which are distinguished solely by difference of position in space. Thus a person, consisting of mind and body, may differ physically from another person solely by the spatial position of his body. (This might happen with identical twins, theoretically.) Duns Scotus, on the other hand, holds that if things are distinct, they must be distinguished by some qualitative difference. This view, clearly, is nearer to Platonism than is that of St Thomas.
Various stages have to be traversed before we can state this problem in modern terms. The first step, which was taken by Leibniz, was to get rid of the distinction between essential and accidental properties, which, like many that the scholastics took over from Aristotle, turns out to be unreal as soon as we attempt to state it carefully. We thus have, instead of 'essence', 'all the propositions that are true of the thing in question'. (In general, however, spatial and temporal position would still be excluded.) Leibniz contends that it is impossible for two things to be exactly alike in this sense; this is his principle of the 'identity of indiscernibles'. This principle was criticized by physicists, who maintained that two particles of matter might differ solely as regards position in space and time—a view which has been rendered more difficult by relativity, which reduces space and time to relations.
A further step is required in modernizing the problem, and that is, to get rid of the conception of 'substance'. When this is done, a 'thing' has to be a bundle of qualities, since there is no longer any kernel of pure 'thinghood'. It would seem to follow that, if 'substance' is rejected, we must take a view more akin to that of Scotus than to that of Aquinas. This, however, involves much difficulty in connection with space and time. I have treated the question as I see it, under the heading 'Proper Names', in my Inquiry into Meaning and Truth.
William of Occam is, after St Thomas, the most important schoolman. The circumstances of his life are very imperfectly known. He was born probably between 1290 and 1300; he died on April 10th, but whether in 1349 or 1350 is uncertain. (The Black Death was raging in 1349, so that this is perhaps the more probable