Aristotle: Nature as Matter and Form

            In his Physics, Aristotle provides an account of nature to better understand the world. In Book 2, he defines nature as: “a type of principle and cause of motion and stability within those things to which it primarily belongs in their own right and not coincidentally,” (Phys. 192b21-23) To better understand this definition, it will be broken down into four sections. First, a “principle” can be understood as a fundamental explanatory basis for a substance; an example would be the thought of the Presocratics, who each thought the world was derived from a certain principle. Thales believed the world came from water, while Anaximenes believed the world came from air. A “principle” can also be understood as an origin, from the Greek arche, where we get “archon” and “monarch.” Second, a “cause of motion;” here, motion (kinesis) is understood as change, and Aristotle sorts change into four types: motion, alteration, growth and diminution, and generation and corruption. Third, “stability” means that natural things will remain the things they are; a horse remains a horse, a tree remains a tree, and horses do not become trees. Lastly, the phrase “primarily belongs in their own right and not coincidentally” means that the nature of a substance is essential to the substance and cannot exist separately, like accidental attributes. For example, a human’s essential attribute is reason, and an accidental attribute could be their height. If a human were incapable of reason, it would no longer be a human, but if a human were of a different height, it would remain a human.

            With nature defined, Aristotle explores what exactly nature is in natural things. Certain individuals believe nature is matter, it lies in what a thing is made of (e.g., a tree is made of wood) (Phys. 193a10-13). Others believe nature is form, it lies in the shape of a thing (e.g., a tree is a tree because it is in the shape of a tree) (Phys. 193a31-193b1). However, Aristotle introduces nature as a combination of matter and form — a hylomorphism (Phys. 194a17-27). He compares nature to craft; a craftsman understands both the matter and form of their craft (e.g., a sculptor understands the shape of the sculpture and the bronze it is made of) (Phys. 194a23-26). Matter can be thought of as potentiality and form can be thought of as actuality, matter cannot exist on its own, but it has the potential to become a substance; to achieve this, it must have a form that actualizes it and turns it into reality (DA, 412a20-28). This interplay between matter and form can be understood through the four causes; these causes define why something is the way it is, why it comes to be and goes away (Phys. 194b17-23). The first cause is the material; it is attributed to a substance’s matter (Phys. 194b24-27). The second cause is the formal; it is attributed to a substance’s form (Phys. 194b27-29). The third cause is efficient, an initiator of motion (e.g., a sculptor for a sculpture), it is best understood in terms of both matter and form but relies more on form (Phys. 194b30-33). The last is the final cause, the end goal of the substance; it relies mostly on form but requires matter (Phys. 194b33-195a3).

            This understanding of nature as a hylomorphism is a critique of Plato. Plato understands the world solely through forms; he separates form from matter, and it exists abstractly in a metaphysical realm that we can only comprehend through reason. In contrast, Aristotle understands the world through matter and form; form and matter are interdependent, and we can only learn about the world through our senses and experience.