Write an essay on Aristotle’s idea of substance.

Aristotle's notion of substance is a foundational concept in his metaphysical philosophy, outlined in works like "Metaphysics" and "Categories." Central to Aristotle's understanding is the distinction between primary substance and secondary substance.

Primary substance refers to individual entities with independent existence – particular substances like individual humans, animals, or plants. Aristotle asserted that primary substances are the ultimate bearers of reality, distinct from mere attributes or qualities.

In contrast, secondary substance pertains to the universal categories that define primary substances – the general kinds or species to which individual entities belong. Secondary substance encompasses the shared characteristics that distinguish, for example, humans as a species.

Aristotle's emphasis on substance aligns with his belief that reality is rooted in individual entities, each possessing a unique essence. Substance, for Aristotle, is not merely a combination of qualities but the underlying reality that unifies diverse attributes in a specific individual.

Furthermore, Aristotle introduced the concept of substantial change, positing that substances undergo transformation while retaining their identity. This idea challenges earlier philosophical views that treated change as mere alteration of qualities.

In summary, Aristotle's idea of substance underscores the significance of individual entities as the fundamental realities in the metaphysical framework. Primary substances, as particular entities, and secondary substances, as universal categories, together form the basis of Aristotle's comprehensive understanding of the nature of being and existence.