Aristotle and Aquinas

To illustrate and examine the relation of religion and morality, I
have chosen Thomas Aquinas, the thirteenth century theologian whose
principles were the standard of ethical teaching up to the
Reformation and since then have become fundamental in Christian moral
theology. Since Aquinas depended so heavily on Aristotle, it will pay
to review the Aristotelian position on ethics, see its religious
dimension, and then study Aquinas somewhat in depth – by way of
contrast with Aristotle as the mainstay of an ethical system which
believes that God and religious values are primary, and that true
goodness is to be measured in terms of an ultimate finality, reasoned
by man's natural intellect but fully possessed only on the basis of
the Christian faith.

The broad outline of Aristotle's teaching is found in the
Nichomachean and Eudemian Ethics, where he writes at great length
of the human good. The good for man, according to Aristotle, is an
active use or exercise of those faculties which are distinctively
human, that is, the powers of mind and will, as distinct from the
lower faculties of feeling, nutrition and growth.

Human excellence thus defined shows itself in two forms: the habitual
subordination of the senses and lower tendencies to rational rule and
principle, and in the exercise of reason in the search for the
contemplation of truth. The former kind of excellence is described as
moral, the latter is intellectual virtue.

A well-known feature of Aristotle's ethics which deeply influenced
Aquinas is the theory that each of the moral virtues is a mean
between excess and defect; thus courage is a mean between cowardice
and rashness, and liberality is a mean between stinginess and
prodigality.

In the Politics, Aristotle sets forth the importance of the
political community as the source and sustainer of the typically
human life. But for Aristotle the highest good for man is found not
in the political life, nor even in the performance of the moral
virtues as such. The highest good consists in the theoretical inquiry
and contemplation of truth. This alone, he says, brings continuous
and complete happiness because it is the activity of the highest part
of man's complete nature, and of that part which is least dependent
on externals, namely the intellect of intuitive reason. Therefore,
contemplation of the first principles of knowledge and being man
participates in that activity of pure thought which constitutes the
eternal perfection of the divine nature, which is God.

In Thomas Aquinas, much of the structure of Aristotle and a great
deal of his insight are retained, to the point that a superficial
reader might suspect that Aquinas merely
put Aristotelian concepts into a Christian mould. Actually the change
from one to the other was radical and a correct understanding of
Christian morality must take this mutation into account.