What modern day philosophy of mind would Descartes adopt if he came here to the present, and could see the new scientific data and philosophical work in the areas of the mind body problem and mental causation?In the Meditations and his correspondence with Princess Elizabeth, Descartes paints a very detailed picture of his strict brand of dualism. But Descartes was a man of science in a time in which science could not completely refute substance dualism. With access to modern day scientific data,Descartes would have defended a cross between dualism and functionalism. I believe he would be compelled to recant his claim for the existence of a true “soul” with its previous attributes, and adjust the definition of the word “soul”. He would put forward that while the concept of a soul is harder to pin down than he had thought, human behavior cannot be explained without introducing the idea of an emergent system of higher order consciousness.
Descartes could still claim that he is a thinking thing, and that his identity is inextricably linked to his consciousness. On the specific case of mental causation, which he argues about with princess Elizabeth, one could put forward that the mind is a highly complex and self aware computational device,which has been formed through natural selection. This still leaves Descartes with his conceptual space which allows him to imagine shapes, objects, and sense memories (Meditation #6 paragraph #9). This space would take the form of a “program” in a purely functionalist sense of the term. The concepts and ideas in this “program” can be said to exist as very complex patterns of brain activity, which can not yet be localized, or found to have a one to one correspondence with the concepts and ideas which are being thought about. A metaphor for how this conceptual space “exists” despite not being a physical object could go something like this: Imagine a deaf man, who has a degree in electrical engineering. If he was born deaf yet understands the properties of circuits and sound waves, no amount of examining the circuitry on a synthesizer will give him insight into how the synth sounds when played. Having been deaf his entire life, he is missing a part of this conceptual “space”, despite not missing any part of his brain. The idea is that investigating the low level (neurons, circuits) can not yield meaningful insight into the high level events (sounds, perceptions of sounds, selfconsciousness).But where is the triangle Descartes mentions, really? And where his intention that causes him to pick up an object ? Elizabeth would say that this directive cannot originate in an immaterial “substance” and cross over to effect the physical world. This is the most intuitive refutation to Descartes claim, but it was not as effective in his time, with limited scientific data. If Descartes could be shown our modern data he may want to edit his work. Data including but not limited to the realms of: physics, chemistry, neuroscience, psychology, computer science and biology. Most specifically would be the process of evolution, and the capabilities of electronic computation devices. If he had accepted these, I would expect him to have a huge problem trying to constrain when exactly immaterial souls started existing. Did a protohuman without a soul give birth to a human with a soul? He believed that animals did not have “minds” like humans do, and he would have to reconcile his theory with the assumption that the mind must have developed gradually.
In “Lonely Souls” Kim very expertly refutes substance dualism, from the privileged perspective that comes with centuries of further scientific knowledge. Descartes would tentatively agree with Kim if exposed to this knowledge, but he would still have the means to refute outright behaviorism( which he would hate) . Where dualism is the most intuitive theory if one only observes the top level (how we all have private subjective mental events), behaviorism could be said to be a theory that only makes sense on the level that it discusses: behavior. Yes people respond to conditioning, as do animals, but putting all our feelings, opinions, intentions and desires into a Skinner box of “conditioned responses” or even “Logical dispositions” is an oversimplification. Even logical behaviourism does not address the processes at work and the most appropriate way to describe them. I hypothesize that it is functionalism, in the vein of what Putnam outlines in “Brains and Behavior” and “ The Nature of Mental States”, which come closest to what Descartes would gravitate towards, once he let go of the completely immaterial mind. Especially in the arena of mental causation. He would like that it allows for private mental events, and that these functional states are states of the mind, but also the whole organism, and can be seen as abstract and subjective, but still a causal force that can present itself in the physical world. Putnam’s nearly suspicious preoccupation with the experience of pain is not far from the central points Descartes puts forward about sensation (meditation 6).He may have liked the idea that while a body is an input and output system, the brain does all of the processing. Where he would most likely differ from pure functionalism, is in the assumption that humans are described simply as turing machines. The main problem Descartes would have, which occurred to me after considering this notion, is that almost any organism, ecosystem, or physical process can be described as the instantiation of a very complex turing machine.
In “Minds, Brains, and programs” Searle points out the key problem with pure functionalism: any conceivable turing machine that only simulates human intelligence does not have the understanding,intentionality, and therefore the same causal properties as a human being, as far as we know right now. So maybe we are turing machines plus intentionality, but where does that intentionality come from? Our type of intentionality exists in the higher level conceptual “space” where we reason, reflect and imagine. This is the pivotal difference between a human mind, and any other naturally occurring or man made turing machine : A human mind is the only thing we know of that is capable of realizing that it may be a turing machine, reflecting on this notion, and in understanding its implications then choose whether or not to believe it. The reflexivity of our consciousness is the main problem that Descartes had with the idea that we are machines. He put animals in this box, claiming that they had perceptions and senses, which could be explained mechanistically but no self conscious, no self awareness, and therefore no ability for self-referentiality, which is much harder to explain from a mechanical standpoint. According to Searle (“Minds, brains, programs” and others) consciousness is a biological process. The evolutionary theory supports this idea. Namely, that our ability to self reflect developed from competencies which adapted in order to make us more successful in our environment. Understanding the causal properties of objects and other people was pivotal to gaining these abilities. The anthropological and cognitive science literature (not sure where specifically, definitely Steven Mithen, Coolidge and Wynn, and Merlin Donald) mostly support the claim that through increased ability to socially manipulate fellow protohumans, our ancestors gained the ability to attribute mental states to our peers based on their behavior. As this developed more completely, we turned it in on ourselves, and were able to reflect on our own ongoing mental states. In recognizing the causal properties of ourselves and others, we came to understand the causal properties of objects, which allowed us to domesticate animals and plants, and eventually build tools, culminating in the most advanced computers of the modern day. This changed the causal nature of a human mind, because it was now the only object with causal properties that understood causation in other objects with causal properties (other humans, animals, and objects). So how does this support dualism? very lightly. The idea( and it is a bit of a stretch) is that according to modern physics (special and general relativity, mostly) one can think of a process as existing, despite not being a physical object, it exists in time and can be defined by the change that occurs on physical matter which is tied to said process. The basic idea is that consciousness is such a process, and the change that it causes can be seen in each specific human body that houses a self aware consciousness. Under these assumptions, one could think of the immaterial mind as some kind of addition. A very complex addition of the mind’s current discrete state, and all of its past states. The mind is the “ticker tape” but it can only be identified by the current state and history of that mind, since we do have memory. This view of processes as “objects in time” can be illustrated in the case of erosion. It can be looked at in general (erosion occurring throughout time, all over the world), or one can look at how it changes a river over the course of millions of years, or one can zoom in even more and look at the slight change that a rock undergoes in a month due to erosion. The key difference between these physical processes and consciousness is that a consciousness can use its current state and past states to create an identity for itself, whereas the river can only be identified as the same from moment to moment by a human mind, which is predisposed to identify things based on past and current states, since this is how it identifies itself.
This modified functionalism seems to be the only option for Descartes, the time traveller who comes to 2015 and must reform his ideas so as to still agree with science.