Celebrating
René Descartes, the first modern philosopher, and his famous phrase
Ego cogito, ergo sum, we call our model for mind the
Ego.
Our
two-stage model for free will we call the
Cogito. Our model for an objective value, independent of humanity, we call
Ergo. And our model for human knowledge we call the
Sum.
The Ego is more or less synonymous with the Self, the Soul, or the Spirit -
Gilbert Ryle's "ghost in the machine." We see it as
immaterial information.
Descartes' illustration of the reflex path from a foot feeling pain from a fire (A), up a nerve to a gland in the mind and back down to pull back the foot (B).
It is important to note that Descartes made the mind the locus of
undetermined freedom. For him, the body is a
deterministic mechanical system of tiny fibres causing movements in the brain (the afferent sensations), which then can pull on other fibres to activate the muscles (the efferent nerve impulses). This is the basis of stimulus and response theory in modern physiology (reflexology). It is also the basis behind connectionist theories of mind. An appropriate neural network (with all the necessary logical connections) need only connect the afferent to the efferent signals. No thinking mind is needed for animals.
Descartes' suggestion that animals are machines included the notion that man too is in part a machine - the human body obeys deterministic causal laws. But for Descartes man also has a soul or spirit that is exempt from determinism and thus from what is known today as "causal closure." But how, we must ask, can the mind both cause something physical to happen and yet itself be
acausal, exempt from causal chains?