In the history of philosophy, there have been two recurrent contrasting conceptions of what is to be human. One we may call Aristotelian and the other Cartesian. (Both can trace their ancestry by the polymorphous Plato)
According to Aristotle, a human being is an animal of a particular kind: a rational animal. According to Descartes, a human person is a spirit of a particular kind, temporarily and mysteriously united to a body.
I accept the Aristotelian account and regard the Cartesian account as fundamentally mistaken.
In skeptical vein, Descartes believed that he could the existence of an external world and the existence of his own body. Is brought his doubt to an end with the famous argument “cogito ergo sum” – I think, therefore I am. This led to the question ‘What am I?’ Descartes’s answer was that he was a substance whose whole essence or nature was to think, and whose being required no place or depended on no material thing. He was an immortal mind, linked to a mortal body which was a particularly elaborated machine.
To Descartes‘s question, my own, and Aristotelian answer, is that I am a human being of a certain kind. We sometimes speak as if we have bodies, rather than we are bodies. But having a body, in this natural sense, is not incompatible with being a body; it does not mean that there is something other than my body that has my body. Just as my body has a head, a trunk, two arms and two legs, so I have a body so I’m not something over and above a body.
As well I have a body, I have a mind. That is to say I have various psychological capacities, including especially an intellect and a will. The intellect is the capacity to acquire and exercise intellectual abilities of various kind, such as the mastery of language and the possession of objective information. The will is the capacity for the free pursuit of goals formulated by intellect. Intellect and will are not themselves independent entities: they are capacities. What are they capacities of? Of the living human being, the bodily person that you would see if you were here in the room where I write.
You too have mind and a body, and so do all human beings: that is to say that we are all bodies that have certain mental capacities. The intellect and the will are peculiar to human beings, but there are other faculties – the ability to see and hear, for instance, and the capacity for pleasure and pain, that we share with others animals. Descartes believed that only human beings were conscious and that other animals were machines lacking consciousness. But Descartes was wrong.
What is peculiar to our species is the capacity for thought and behavior of the complicated and symbolic kinds that constitute the linguistic, social, moral, economic, scientific, cultural and other characteristics activities of human beings in society. The mind is a capacity – not an activity. It is the capacity to acquire intellectual abilities of which the most important is the mastery of language. The will, in contrast with animal desire, is the capacity to pursue goals that only language-users can formulate. The study of acquisition and exercise of language is the way par excellence to study the nature of the human mind. It is because Descartes did not take this fact seriously that his philosophy of mind fell into error. When he tried to doubt everything, the one thing he did not call into question was the meaning of the words he was using in his solitary meditation. Had he done so, he would have had to realize that even the words we use in soliloquy derive their meaning from the social community which is the home our language, and that therefore it was not, in fact, possible to build up his philosophy from solitary private ideas.
Anthony Kenny, “what I believe”