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Thomas Aquinas (1225–1274)

29 September, 2015 - 10:13

Thomas Aquinas synthesized Aristotelian and Christian thought into a nearly seamless whole. It is not an exaggeration to say thatevery philosopher for the next five hundred years stood in his shadow.

Like Aristotle, Aquinas is an empiricist in both senses of the term: he thinks that all the materials for knowledge come from sensation,and that all justifications ultimately depend on experience. He is also an existentialist, in the sense discussed in the Epistemology .

Despite his often technical formulations, Aquinas aims to give a commonsensical account of metaphysics and epistemology, just asAristotle did.

Our first reading is a short statement of Aquinas’s views on the cosmological argument. This argument for the existence of God,in its crudest form, runs thus:

  1. Everything must have a cause.
  2. There must be a first cause, i.e., a cause that does not itself have a cause.
  3. The first cause is God.

Like all a posteriori arguments—arguments from experience—this one has a problem in the move from (ii) to (iii). Why not thinkthat the first cause is the Jonas brothers, or a clam? Why should we believe that the first cause still exists? Aquinas himself runsinto these problems. Thus a later philosopher, John Duns Scotus, argues that Aquinas’s famous ‘five ways’ might prove the existenceof five distinct beings.

  1. As a good justification empiricist, Aquinas is committed to proving God’s existence from experience; he cannot evadeDuns Scotus’s objections. Nevertheless, Aquinas does not think the cosmological argument is a good one. Can you seewhat goes wrong in premises 1 and 2?

Aquinas has other criticisms of his own, criticisms that would apply even to the most sophisticated versions of the cosmologicalargument. These tell us much about how Aquinas conceives of causation.

Aquinas’s thoughts here landed him in trouble with the establishment. In 1277, three years after his death, his views on the cosmologicalargument were condemned. Why?