Preface

...of animals, as the Philosopher Aristotle shows in the second book of On the Soul, saying: "The most natural of works is for each thing to generate another like itself, so that they may participate in the divine and immortal being; for all things desire this so that they may remain—not as the same individual in number, but as the same in species." For this reason, the Commentator Averroes says in the second book of On the Soul that because divine providence original: "sollicitudo divina" could not make the individual human being remain the same in number, it took pity on him by giving him the power by which he could remain the same in species. And he adds: "For there is no doubt that it is better to have this power than not to have it, or not to exist at all."

This is the executive part in which the author pursues his intent by putting forward two propositions serving his purpose. It is divided into as many chapters and parts as will appear in order. Note: the generation of perfect animals is eternal, because such things belong to the universal perfection of the world, according to the first book of the Ethics. But a doubt seems to arise, because certain animals are at times entirely destroyed, such as certain worms and flies in winter. It must be said that if they are destroyed in one climate, they are then generated in another, according to Albert Albertus Magnus and in the commentary on the first book of the Posterior Analytics. Or it must be said that the generation of animals is eternal because they belong to the universal perfection; but if the first solution stands, it is doubtful whether those animals belong to the universal perfection, because it would be better for many animals not to exist than to exist—namely snakes and animals that are poisonous. It is said that it is good for them to exist so that they may absorb the impurities of the earth; for if they did not absorb them, they would infect the air, and consequently, man. Hence, nature displays nothing without a reasonable cause. From that text, it is clear that chastity is a sin against nature—although for men it is a way of death by the precept of the law—because through chastity an animal does not generate its like. Note: by "divine providence" one cannot understand God Himself, because He does not care for particulars according to Averroes in the twelfth book of the Metaphysics; therefore, by divine providence is understood the celestial body, which by its own nature and natural appetite desires to preserve these lower things, though mediated by the governance of the Intelligences The spiritual beings or "angels" believed to move the celestial spheres. Hence the Commentator in the twelfth book of the Metaphysics says: "The work of nature is the work of an Intelligence that does not err." Can the generation of animals preserve animals in their specific being forever? It is said no, because if so, the species would be capable of being generated i.e., having a beginning in time, which is false: