…rational certainties that are likewise confirmed by sense perception and reason—indeed, matters of even greater moment? The pleasure that arises from them is a lofty, spiritual and intellectual joy; and the more complete a person’s intellect becomes, the more he loves this joy over that bodily delight.
Moreover, the philosophers affirmed the return of souls and the existence of intellectual bliss, grounding both upon these very propositions that they call “common notions.” If those propositions were not really known, nothing they have established would qualify as knowledge. In truth, they merely echo what others say: that inward pleasures are stronger and nobler than outward, sensible pleasures, and they claim self-evidence when asserting a delight that lies beyond manifest physical enjoyments.
If pleasure is, as some of them maintain, the perception of that which suits one’s nature—or, more accurately, a feeling that necessarily accompanies such perception—then it is clear that knowledge, justice, truthfulness and beneficence are congenial to the children of Adam. They therefore take pleasure in them, and their delight in them is greater than in anything else. That is what it means for an act to be good; its being evil is simply the opposite.
Once the meanings of good and evil are understood, it becomes evident that these common notions are among the greatest certainties. The nations have not agreed upon them only through sense, reason and experience; their consensus here surpasses their agreement on almost anything else. Whole groups may live for generations without ever entertaining the universal intellectual propositions that logicians treat as first principles of science—such as the axiom that affirmation and negation cannot coexist, or that if a particular thing exists it cannot at the same time be nonexistent. The universal proposition may never occur to them; indeed, most people never even conceive the impossible union of existence and non-existence. Yet there is no community that does not regard justice, truthfulness and knowledge as good, and their opposites as evil.
Furthermore, wisdom—according to them and to every nation—falls into two kinds: theoretical and practical. Muslims speak of the same dual wisdom. Imam Malik, may Allah have mercy on him, said, “Wisdom is to understand the religion and to act upon it.” Ibn Qutaybah likewise stated, “Among the Arabs, wisdom is knowledge joined to action.” Practical wisdom, in their usage and in that of others,