History of Monsters. 381

proposing the causes of monsters, authors differ in their opinions. Some attribute the causes of monsters to a poor temperament in the parents, others to absurd imaginations, others to divine wrath, others to constellations and previous planetary alignments, some to nature transferring the strength of many parts into a single limb, others to the power of an evil demon, and finally, some reduce these causes to the mating of animals of different species.

In the present context, as we contemplate monsters as works of nature, we must derive their origin from the four primary categories of causes: material, final, efficient, and formal. Monsters are said to have a material cause because whatever is produced by nature—whether intentionally or accidentally—undoubtedly results from some pre-existing subject. They have a final cause because nature does nothing in vain; instead, all things are directed toward some end. They have an efficient cause because every product is created by some producer. Finally, they have a formal cause because all works of nature follow a specific form.

In explaining these specific causes of monsters, we will first examine the material cause. This has claimed the name of "cause" for itself since antiquity; some have suggested that the word "cause" is derived from "chaos" (with the aspiration removed), because that confused matter was the first to take on the forms of all things. Furthermore, all philosophers and physicians seem to assign the causes of all monsters to seminal matter. For this reason, Democritus condemned overly frequent sexual intercourse, as he believed that monsters often resulted from this abundance of seed. Empedocles reported that monstrous births were generated due to an excess or deficiency of seed, or its agitation.

Aristotle also places the primary cause of monsters in matter, occurring when nature, in the construction of parts, deviates from the right path due to an excess or deficiency of material, or because it is transferred to a part or location where it was not needed. In such cases, two parts are corrupted: one suffering from deficiency and the other from excess. Indeed, if two similar parts are generated and one is superfluous, it happens because the seminal matter in the womb is divided, either by movement or by gas. Thus, the matter intended for the generation of fingers is separated and carried elsewhere; wherever it settles, a superfluous part is created. Even if such matter reaches the head, it is not transformed into the substance of the head but into fingers, because the matter contains within itself the power of the limb from which it originally departed. This is why, in the dissection of human corpses, one often observes multiple kidneys, emulgent veins, and duplicated spermatic and genital vessels; this occurs due to untimely lust, which is practiced more frequently by humans than by beasts.

Galen, adhering to the opinion of Empedocles, teaches that monsters are born if the seed is too abundant or too sparse, or if it is introduced with immoderate motion; or because it has acquired an addition, a diminution, a transposition, or an inflammation. He adds further, following the opinion of several physicians, that a poor conformation of the womb may be a cause.

Johannes Grammaticus, in his commentaries on the *De Anima*, supports Aristotle’s view. Cardan reduces the causes of monsters to the flexibility and disposition of matter; for this reason, he observes that monsters are more frequent among lowlier and imperfect animals than among perfect ones. Consequently, he admits that monsters are more rarely produced by human or elephantine nature. When the poet Gunther observed that lowlier and imperfect creatures were often born monstrous, he assigned the cause of monsters to the dross of natural materials, which, lacking the power of perfect creation, brings forth monstrous offspring. Thus he sings:

What remains, taxing the world itself and the order of things, is everywhere rejected; hence the sudden, monster-bearing births of men and cattle.

But rejecting these as the trifles of poets, we turn to the opinion of Albertus Magnus, who places the cause of monsters in the matter and in the manner of the creation of that which is conceived. Indeed, he adds that monsters occur due to some error in the operation