Substantial form

has been abandoned for a mechanical, or "bottom-up" theory of organization.

Early adoption

Both Platonic and Aristotelian forms appear in medieval philosophy.

Medieval theologians, newly exposed to Aristotle's philosophy, applied hylomorphism to Christianity, such as to the transubstantiation of the Eucharist's bread and wine to the body and blood of Jesus. Theologians such as Duns Scotus developed Christian applications of hylomorphism.

The Aristotelian conception of form was adopted by the Scholastics, to whom, however, its origin in the observation of the physical universe was an entirely foreign idea. The most remarkable adaptation is probably that of Aquinas, who distinguished the spiritual world with its subsistent forms (formae separatae) from the material with its inherent forms which exist only in combination with matter.

Criticism

Descartes, referring to substantial forms, says:

They were introduced by philosophers solely to account for the proper action of natural things, of which they were supposed to be the principles and bases ... But no natural action at all can be explained by these substantial forms, since their defenders admit that they are occult, and that they do not understand them themselves. If they say that some action proceeds from a substantial form, it is as if they said it proceeds from something they do not understand; which explains nothing.

Response to criticism

Leibniz made efforts to return to forms. Substantial forms, in the strictest sense for Leibniz, are primitive active forces and are required for his metaphysics. In the Discourse on Metaphysics (§10):

[...] the belief in substantial forms has a certain basis in fact, but that these forms effect no changes in the phenomena and must not be employed for the explanation of particular events.