In the period between his two stays in Athens, between his times at the Academy and the Lyceum, Aristotle conducted most of the scientific thinking and research for which he is renowned today. In fact, most of Aristotle's life was devoted to the study of the objects of natural science. Aristotle's metaphysics contains observations on the nature of numbers but he made no original contributions to mathematics. He did, however, perform original research in the natural sciences, ., botany, zoology, physics, astronomy, chemistry, meteorology, and several other sciences.
For Aristotle, the form is not something outside the object, but rather in the varied phenomena of sense. Real substance, or true being, is not the abstract form, but rather the concrete individual thing. Unfortunately, Aristotle's theory of substance is not altogether consistent with itself. In the Categories the notion of substance tends to be nominalistic (that is, substance is a concept we apply to things). In the Metaphysics , though, it frequently inclines towards realism (that is, substance has a real existence in itself). We are also struck by the apparent contradiction in his claims that science deals with universal concepts, and substance is declared to be an individual. In any case, substance is for him a merging of matter into form. The term "matter" is used by Aristotle in four overlapping senses. First , it is the underlying structure of changes, particularly changes of growth and of decay. Secondly , it is the potential which has implicitly the capacity to develop into reality. Thirdly , it is a kind of stuff without specific qualities and so is indeterminate and contingent. Fourthly , it is identical with form when it takes on a form in its actualized and final phase.
'race' - genos - literally, 'kind' or 'birth.' As used at 1155a15-20, as in general throughout Aristotle, it clearly refers to the human 'race,' the dog 'race,' etc., . to kinds of animals - not to what is known today as a race or ethnicity. The word genos is the root of the modern scientific term 'genus,' and can often be understood as 'genus' (or sometimes 'species'). The word can also refer to a 'kind' of thing, or to one's clan, family, or nationality; but most often in Aristotle, and certainly from the context here, it refers to a kind of animal: humankind, dog-kind, etc.