Thomas Aquinas is generally regarded as a pillar of orthodoxy, the cornerstone of an intellectual establishment. He achieved a synthesis that almost became something of this sort, although his impact is often exaggerated. In his own time he challenged accepted tradition on a number of points and was condemned by ecclesiastical authorities.

The principal point at issue in this condemnation is a doctrine of Thomas Aquinas that may sound bizarre to many today : the ‘unicity of the substantial form'. It is central to his anthropology and has serious consequences for his ethics. It was regarded by many of his contemporaries as heretical or at least dangerous. And if one were to attempt to place Aquinas in the Marxist-Leninist division of all thinkers into idealists and materialists, this doctrine would earn him a place among the materialists.

I shall not attempt a textual analysis of the problem involved. This would inevitably demand a highly technical discussion in the peculiar language of thirteenth-century scholasticism. Rather, I should like to attempt a description of what I believe to have been Aquinas’s view of man and ethics in terms of our own popular picture. I believe that this view can be substantiated through serious historical research and that it is, within the limits imposed by the language gap, a faithful picture of the position of Thomas Aquinas.

It is often assumed that the ethic of Thomas Aquinas is otherworldly, based on a spiritualist anthropology, and ultimately, rationalist. The first assertion is a half-truth; the second and third are false. Aquinas’s anthropology is materialistic, and he is no rationalist.