Aristotle's Four Causes

Aristotle first defines what causes are in the metaphysics (1013a25-35). He attributes four causes to change: the material cause, the formal cause, the moving cause and the final cause. The material cause is mainly associated with the substance the thing is made from. An example of this can be bronze to a statue. The formal cause is defined as the essence of the thing we are talking about. Without a formal cause, the thing is only a potential and cannot perform the functions that it is supposed to. The third cause, the moving cause, is the cause that first sets the change in motion. In the case of the statue, this would be the sculptor or the art of sculpting. The final cause is the goal we are working towards or the thing we hope to achieve

According to Aristotle the body is the material cause and the soul its formal cause (412a16-412b1). His reason for this is that the formal cause or the essence is the main qualifier we use to call a thing “that”. For example, in the case of an eye, the essence can be sight. An eye can have all the right parts but without sight, the eye cannot perform the function it was made for. The same can be said for a body. A dead body could have the right organs in the right places and still it would not qualify for a human being because it lacks the essence that makes a living thing. We can then think of the body as a potential living thing that needs the essence, soul, to make it an actuality or a living

The first possible answer Aristotle looks at is nutrition. Nutrition is a common function of all living things including plants because it is the one function all living things need to perform to sustain life. Another function that most but not all living things perform is sense which includes awareness of possible pleasures and pains to the organism. He also recognizes motion as the common function of all animals. (414a26-414b1)

While the three functions are helpful in classifying other living organisms, human beings have an additional function they perform which sets them apart from all other living things: thought. Thought Aristotle says is a function unique to humans and the divine (415a8-10). The essence of being human must not then lie in what is common to all beings; rather, it must be dependent on what is unique to humans alone (1098a1-5). Therefore, the function of a human being lies in reason, not in other parts of the soul, and is living a life of reason and