(For previous posts in this series, see here.)

The philosopher Gilbert Ryle (1900-1976) didn’t think much of Rene Descartes’ idea of a disembodied mind, using its free will, acting as some kind of captain of the body, and coined the derogatory term ‘the Ghost in the Machine’ for it.

There is a doctrine about the nature and place of minds which is so prevalent among theorists and even among laymen that it deserves to be described as the official theory… The official doctrine, which hails chiefly from Descartes, is something like this. With the doubtful exception of idiots and infants in arms every human being has both a body and a mind. Some would prefer to say that every human being is both a body and a mind. His body and his mind are ordinarily harnessed together, but after the death of the body his mind may continue to exist and function. Human bodies are in space and are subject to mechanical laws which govern all other bodies in space… But minds are not in space, nor are their operations subject to mechanical laws…

…Such in outline is the official theory. I shall often speak of it, with deliberate abusiveness, as “the dogma of the Ghost in the Machine.” (quoted by Stephen Pinker, The Blank Slate, p. 9)

Ryle’s skepticism about the Cartesian dualistic model is being validated as our understanding of the brain increases. The idea of some centralized information gathering and decision-making location in the brain has become increasingly untenable. We now know that the brain is a material entity, consisting of specialized cells (called neurons) connected to each other (by things called synapses), with the entire system serviced by blood vessels and glands that secrete chemicals. While there are some localized regions dealing with specific functions (such as sight and smell), the brain activity that we are aware of, such as thoughts and feelings, consist of patterns of complex neutral activity that are spread over large parts of the brain, with individual neurons firing in response to stimuli received from other neurons and the external environment. There does not seem to be any evidence of some kind of command center where decisions are made.

And yet we have a strong sense of the existence of things like the ‘will’ and ‘consciousness’, which are the attributes we assign to the Ghost in the Machine. The challenge is to understand them in terms of the workings of the material substrate of the brain.

In the first post in this series, I said that belief in an independently existing mind shares many similarities with the belief in god. One important difference between the mind and god is that each one of us is assumed to possess our own mind with its own identity, while god is a single universal entity. A second difference is that our personal entity can only interact with our own neurons and thus control our own thinking and actions and not those of others while god supposedly can control everyone’s thinking and even move physical objects like mountains if he wants to. (I am going to ignore the weak evidentiary claims for the existence of telekinesis, extra-sensory perception, mind control, and the like)

But those differences are not the ones that are most relevant to the problem of free will. The key problem is the implausibility of the idea that there exists a dualism, a mind-body distinction in which an independently existing non-material mind can influence the body.

I find the idea of a personal, independently existing, conscious, non-material, entity that I can call my ‘mind’ as hard to accept as the existence of god, and for all the same reasons. Assuming that such a thing exists causes far more problems than it solves. It seems so much more likely that what I call my mind or my will, rather than controlling my body, is actually the product of my body, caused by the firing of the neutrons in my brain, and the firing of any one of those neurons is in response to the stimuli it receives either from other neurons or, if it is a neuron that is directly connected to a sensory organ such as the eye or nose, the sensations my body receives from the external world.

All of my brain’s workings arise from my personal life history that has made my body what it is and created my brain and its neural networks. In other words, ‘I’ am a unitary system, not a dualistic one, made up of material objects obeying the laws of nature. This process, acting over the duration of my personal life history as well as the longer term evolutionary history, has created a brain that in turn makes decisions that influence my body, leading to new experiences that further shape my brain, and so on. It is a self-contained and closed system that does not require some external non-material entity that interacts mysteriously with it.

But the implication of this unitary view of the body is that any decision I make is completely determined by the facts of my personal history and the external stimuli that I experience at any moment. Although I may think that there is another ‘I’ within my body making decisions freely using my ‘free will’, this perception is an illusion and the reality is that the decisions are the consequences of the laws of nature simply working their way through my material body.

Next: To what extent are we strictly deterministic animals?