Substance and what it means to be › Being Without Flattening the Differences

Book IV.1 proposes a science of being qua being. Qua means in the capacity of, or insofar as. A specialist inquiry studies things under a restricted aspect; Aristotle's proposed inquiry considers what belongs to things insofar as they are beings. He is not proposing an encyclopedia containing all the findings of every particular discipline. He is asking about principles that bear on being generally.

An immediate difficulty is that being has several senses. A person is, a quantity is, and a quality is, but their modes of being need not be identical. In IV.2 Aristotle compares this pattern to the different ways something can be called healthy. A condition may be healthy because it preserves health, while another thing is called healthy because it indicates health. The meanings are connected through a central reference, rather than being unrelated coincidences of language.

He proposes a corresponding connection among senses of being, with substance as their focal reference. A quality can be a quality of a substance; a process can be a coming-to-be or destruction of substance. This gives the investigation a direction without requiring every being to belong to one undifferentiated category. To understand being generally, Aristotle gives priority to understanding substance.

The distinction can discipline an ordinary discussion. Suppose a project report gives an average response time without identifying which requests it measures. The number may be perfectly calculated while its application remains unclear. This contemporary analogy illustrates the need to identify the subject of a predication. It does not establish Aristotle's theory of numbers, or prove that every statistic is metaphysically an accident of one substance.