Descartes asserts that bodies are believed to exist in space, subject to mechanical laws and can be observed externally. Minds are not in space, are not subject to mechanical laws, and its working is unfathomable to other observers. Thus, the body is external, and the mind becomes internal. This metaphor of ‘the inner and outer’ gives rise to the assumption that there are two kinds of existence. Physical existence has the necessary feature of being in space and time, and is composed of matter. Mental existence has the necessary feature of being in time, but not in space, and is composed of consciousness. But there is a logical absurdity in the concept of the mind having a parallel, non-material existence of its own corresponding to the material existence of the body. It may be said that Descartes was motivated by conflicting motives in an attempt to reconcile religion and science by formulating the dualist concept of mind. People must refer to patterns that include bodily behavior, which everyone can see, and not to processes in a soul which is hidden from view. Since we observe these patterns in one another’s behavior, we can know other person’s have mental states like ours. However, Ryle argues that Descartes makes a category mistake by saying that there is something called “mind” above a person’s behavioral dispositions. Ryle himself suggested dualism’s replacement, the dispositional concept of mind. It states that to have a mind is to have the capacity, disposition, or potential to (1) take in inputs, (2) process these inputs, and (3) generate corresponding outputs as needed. This is the reason why humans, animals, and machines may be said to equally have minds. Obviously humans, animals, and machines in fact have the capacity to do the three things required to have a mind.
It still appears that only humans have minds and not machines and animals because of the notions Descartes proposes. He proposes that humans too are like machines. But, we are vastly more intricate than hydraulic automata. Unlike machines, humans are capable of thought and language. Machines can still come up with the “correct” response without knowing what the concept really means. Machines can manipulate algorithm and syntax, but it cannot get any closer to meaning. As for the animals, Descartes argues that animals are purely beastly mechanisms. Animals do have sensations, but these are merely innate reflexive behaviors. Animals lack thought and language. Humans have the necessary actions – not just cause and effect but also willingness. Critically, we have a “rational soul,” existing outside of the body. He argues that humans are special. Reason, ethics, and language are unique to humans. These allow humans to respond to any conditions and to attain mastery over nature.