Thomas Aquinas

Beware the man of a single book.

The study of truth requires a considerable effort—which is why few are willing to undertake it out of love of knowledge—despite the fact that God has implanted a natural appetite for such knowledge in the minds of men.

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

Three things are necessary for the salvation of man: to know what he ought to believe; to know what he ought to desire; and to know what he ought to do.

The slenderest knowledge that may be obtained of the highest things is more desirable than the most certain knowledge obtained of lesser things.

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

It is requisite for the relaxation of the mind that we make use, from time to time, of playful deeds and jokes.

All that I have written seems like straw compared to what has now been revealed to me.

Good can exist without evil, whereas evil cannot exist without good.

The truth of our faith becomes a matter of ridicule among the infidels if any Catholic, not gifted with the necessary scientific learning, presents as dogma what scientific scrutiny shows to be false.

All that I have written seems like straw to me.

To one who has faith, no explanation is necessary. To one without faith, no explanation is possible.

With regard to heretics two points must be observed, one on their side, the other on the side of the Church. As for heretics their sin deserves banishment, not only from the Church by excommunication, but also from this world by death.

To corrupt the faith, whereby the soul lives, is much graver than to counterfeit money, which supports temporal life.

Since forgers and other malefactors are summarily condemned to death by the civil authorities, with much more reason may heretics as soon as they are convicted of heresy be not only excommunicated, but also justly be put to death.

The inferiority of women lies not just in bodily strength but in force of intellect.

Feminine intellectual inferiority actually contributes to the order and beauty of the universe.

Women are by nature 'deficient and misbegotten.'

The essential value of her creation is 'for the generation of the species.'

Women are important not for any inherent value or virtue, but for their ability to reproduce.