A man has free choice to the extent that he is rational.
Saint Thomas Aquinas

All that is true, by whomsoever it has been said has its origin in the Spirit.
Saint Thomas Aquinas

All the efforts of the human mind cannot exhaust the essence of a single fly.
Saint Thomas Aquinas

As regards the individual nature, woman is defective and misbegotten, for the active power of the male seed tends to the production of a perfect likeness in the masculine sex; while the production of a woman comes from defect in the active power.
Saint Thomas Aquinas

Because of the diverse conditions of humans, it happens that some acts are virtuous to some people, as appropriate and suitable to them, while the same acts are immoral for others, as inappropriate to them.
Saint Thomas Aquinas

Because philosophy arises from awe, a philosopher is bound in his way to be a lover of myths and poetic fables. Poets and philosophers are alike in being big with wonder.
Saint Thomas Aquinas

Better to illuminate than merely to shine, to deliver to others contemplated truths than merely to contemplate.
Saint Thomas Aquinas

Beware of the person of one book.
Saint Thomas Aquinas

By nature all men are equal in liberty, but not in other endowments.
Saint Thomas Aquinas

Clearly the person who accepts the Church as an infallible guide will believe whatever the Church teaches.
Saint Thomas Aquinas

Faith has to do with things that are not seen and hope with things that are not at hand.
Saint Thomas Aquinas

Friendship is the source of the greatest pleasures, and without friends even the most agreeable pursuits become tedious.
Saint Thomas Aquinas

Good can exist without evil, whereas evil cannot exist without good.
Saint Thomas Aquinas

Happiness is secured through virtue; it is a good attained by man's own will.
Saint Thomas Aquinas

Hold firmly that our faith is identical with that of the ancients. Deny this, and you dissolve the unity of the Church.
Saint Thomas Aquinas

How can we live in harmony? First we need to know we are all madly in love with the same God.
Saint Thomas Aquinas

How is it they live in such harmony the billions of stars - when most men can barely go a minute without declaring war in their minds about someone they know.
Saint Thomas Aquinas

Human salvation demands the divine disclosure of truths surpassing reason.
Saint Thomas Aquinas

If forgers and malefactors are put to death by the secular power, there is much more reason for excommunicating and even putting to death one convicted of heresy.
Saint Thomas Aquinas

If the highest aim of a captain were to preserve his ship, he would keep it in port forever.
Saint Thomas Aquinas