PREFACE

...always in its specific being? It is said that it is not, because if it were so, then the species would be subject to generation meaning the species itself would be born and die, which is false. This falsehood is evident because the species is perpetual. I say that when this or that individual is generated, then the specific nature the essential qualities that make a thing what it is, such as "human-ness" or "horse-ness" is generated under this designated being, and according to a part, even though it is not generated according to its whole extent. Wherefore, note that nature works hiddenly in universals, as Gilbert de la Porrée Gilbert de la Porrée (c. 1070–1154) was a prominent French scholastic philosopher and theologian; his "Book of the Six Principles" was a standard logic textbook in medieval universities. says in his Six Principles in chapter 1, namely in the chapter on form. And because nature intends to produce a human nature—namely, "man" in general or "horse" in general—and yet it produces a particular individual, such as "Socrates" original: "Sortem," a standard medieval shorthand for Socrates used as a generic name for an individual person., this occurs because it finds a certain matter that is designated in this determined place. Therefore, if nature found all the matter at once, it would produce every man at once; but because it finds only one portion of the menstrual fluid In medieval biology, based on Aristotle, it was believed the mother's menstrual blood provided the "matter" for a child, while the father's seed provided the "form" or soul. of this or that woman, it produces this or that particular man.

Moreover, the reason why these animals, and especially humans, do not endure according to the same nature, matter, and number meaning the exact same individual does not live forever, is stated in the second book of On Generation and Corruption Aristotle’s treatise on the processes of coming-to-be and passing-away.. Those things whose bodily substance does not endure, but is corruptible, could not repeat as the same individuals in number; rather, the substance of man...