Abstract
Given that they are chance events, there can be no scientific demonstration or knowledge of monsters. There are still, however, many recognizable elements of scientific explanation in Aristotle's Generation of Animals Book IV chapter 4. What happens in cases of monsters and deformities occurs in the process of generation, and there is much that we can know scientifically about this process—working from the animal’s essential attributes outward to factors that influence these processes. In particular, we find Aristotle looking for and investigating whether “for the most part” correlations are causally relevant and linked to essence. Even though the birth of monsters is scientifically inexplicable, the features of animals that tend to produce them can be known about. I will explain how it is that producing more than one offspring per birth is a knowable feature of a kind. This feature, along with others, can then give us a much better grasp on what happens in particular instances of monstrous birth.