 The word “form” may misleadingly suggest that what is acquired in a case of substantial generation is simply a shape, and this impression is reinforced by some of the examples that Aristotle uses, especially when focusing on artefacts: plausibly the form of a bronze statue just is its shape. When we consider organisms, however, it becomes apparent that having the right shape is not sufficient to possess the form. A thing’s form is its definition or essence—what it is to be a human being, for example. A statue may be human-shaped, but it is not a human, because it cannot perform the functions characteristic of humans: thinking, perceiving, moving, desiring, eating and growing, etc. The connection between a thing’s form and its function emerges in Physics ii 3, where Aristotle distinguishes his four kinds of cause: material, formal, efficient, and final, and suggests a special connection between the formal and final cause.