Summa contra Gentiles1.2 Chapter II. The author's intention in this work

Now of all human pursuits, that of wisdom is the most perfect, the most sublime, the most profitable, the most delightful, lit is the most perfect, since in proportion as a man devotes himself to the pursuit of wisdom, so much does he already share in true happiness: wherefore the wise man says (Ecclus. xiv.?): Blessed is the man that shall continue in wisdom, It is the most sublime because thereby especially does man approach to a likeness to God, Who made all things in wisdom: wherefore since likeness is the cause of love, the pursuit of wisdom especially unites man to God by friendship: hence it is said (Wis. vii. 14) that wisdom is an infinite treasure to men: which they that use, become the friends of God. fit is the most profitable, because by wisdom itself man is brought to the kingdom of immortality, for the desire of wisdom bringeth to the everlasting kingdom (Wis. vi. 21). ' And it is the most delightful because her conversation hath no bitterness, nor her company any tediousness, but joy and gladness (Wis. viii. 16).

Wherefore, taking heart from God's lovingkindness to assume the office of a wise man, although it surpasses our own powers, the purpose we have in view is, in our own weak way, to declare the truth which the Catholic faith professes, while weeding out contrary errors; for, in the words of Hilary, 7 acknowledge that I owe my life's chief occupa- 1 Ps. ciii. 24. 3 De Trin. i. 37.

tion to God, so that every word and every thought of mine may speak of Him. But it is difficult to refute the errors of each individual, for two reasons. First, because the sacrilegious assertions of each erring individual are not so well known to us, that we are able from what they say to find arguments to refute their errors. For the Doctors of old used this method in order to confute the errors of the heathens, whose opinions they were able to know, since either they had been heathens themselves, or had lived among heathens and were conversant with their teachings.\ 'Secondly, because some of them, like the Mohammedans and pagans, do not agree with us as to the authority of any Scripture whereby they may be convinced, in the same way as we are able to dispute with the Jews by means of the Old Testament, and with heretics by means of the New: whereas the former accept neither. Wherefore it is necessary to have recourse to natural reason, to which all are compelled to assent. And yet this is deficient in the things of God.

And while we are occupied in the inquiry about a particular truth, we shall show what errors are excluded thereby, and how demonstrable truth is in agreement with the faith of the Christian religion.