Full Idea
The form of a thing (of a given kind) explains why certain matter constitutes a thing of that kind, and with this, Aristotle holds, we have reached explanatory bedrock.
Gist of Idea
Form explains why some matter is of a certain kind, and that is explanatory bedrock
Source
Michael V. Wedin (Aristotle's Theory of Substance [2000], Intro)
Book Reference
Wedin,Michael V.: 'Aristotle's Theory of Substance' [OUP 2000], p.7
A Reaction
We must explain an individual tiger which is unusually docile. It must have an individual form which makes it a tiger, but also an individual form which makes it docile.