Substantial Form

Substantial form is a philosophical concept that refers to the essential nature or defining structure of a thing, which makes it what it is. It’s what gives an object its identity and properties, beyond just its physical parts. For example, the shape and purpose of a chair constitute its substantial form, distinguishing it from other objects. In essence, it’s the underlying "pattern" or "essence" that organizes matter into a specific kind of thing, enabling us to recognize and differentiate it from other objects.