Readings
Texts
- Plato, "The Republic", Book IV (selections) (from last time)
- Aristotle, "De Anima", (selections) (from last time)
- Descartes, "Meditations: Meditation VI"
- Hume, "An Enquiry Concerning Human Understanding", (selections)
Notes
- The Platonic Soul (from last time)
- The Aristotelian Soul (from last time)
- The Mind-Body Problem
- Cartesian Dualism
- Humean Psychology
Videos
Synopsis
Recall the question I asked last time, what are the differences to be found between my recent biography and that of a rock? Another way to put the same point is a thought experiment with which I began the class today, what is the most remarkable thing to be found on the beach?. After cataloging the many beautiful, amazing, curious, and intriguing things we find on the beach, I suggested that the most remarkable thing to be found on the beach is, unequivocally, you. After all, you alone of all the things found on the beach are amazed by what you find, curious about what you find, delighted by what you discover, awed by the beauty you experience, and so on.
We continued our historical survey of the philosophy of mind today by leaping from the classical period--Plato (427-347 BCE) and Aristotle (384-322 BCE)--to the modern period--Descartes (1596-1650) and Hume (1711-1776)--in Philosophy. This is not to suggest that the 1918 years between the death of Aristotle and the birth of Descartes was devoid of philosophical inquiry into the mind. Nor should it be thought that we have examined the positions of the philosophers we happen discuss in anything approximating the detail they deserve.
This is not, however, a course on the history of the philosophy of mind. Rather, we are conducting an all-too-brief survey of major philosophers to help us locate our subsequent examination of current issues in Cognitive Science and the foundations of Artificial Intelligence. We want to know, what are some of the things historically important philosophers have said which will ultimately bear on and inform our investigations? This is especially important as the authors we'll be reading later in the class often refer back to the major philosophers and their positions.
One of the most important philosophers of mind is, indisputably, Descartes. After a brief discussion today of Descartes' epistemological project to reconstruct all of human knowledge on a firm foundation--that is, on the foundation of just those propositions which cannot be doubted--we examined Descartes' arguments for Cartesian Dualism or Interactionism, his solution to the Mind-Body Problem.
What is the Mind-Body Problem, precisely?
We must grant that the mind and the body qua physical object have very different--radically different, in fact--kinds of properties. Indeed, let us be clear that this is the so-called Mind-Body Problem: None of the properties we ordinarily attribute to minds (having beliefs, having desires, having intentions, and so forth) or properties we ordinarily attribute to everyday physical objects, nor are the properties we ordinarily attribute to everyday physical objects (having extension, having mass, having color, having location, and so forth) are properties we ordinarily attribute to minds; what, then, is the place of mind in nature?
We can think of the Mind-Body Problem as a gap or, really, rift in nature. None of the properties we ascribe to minds we ascribe to bodies, except perhaps metaphorically, and none of the properties we ascribe to bodies we ascribe minds, except, again, perhaps as a matter of metaphore. To say I feel blue today does not mean my mind suddenly has a color!
Descartes, swayed by such considerations, argues that the mind and the body are distinct, but causally interacting, substances. That is, he claims that mind is an entirely different kind of substance than body, and he bridges the gap or rift between the two by asserting that physical events cause mental events and mental events cause physical events. Nevertheless, mind and body are distinct substances. Thus the natural world is richer or more complex than we initially take it to be, for Descartes, because the way to account for the radically incompatible properties of bodies and minds is to recognize that those properties are of two radically different substances.
How, then, do they interact, if these substances (the material or physical and the mental) are so radically different in nature? Solving this problem leads Descartes to do a lot of hand-waiving, some of which involves the pineal gland. In the end it is not at all clear that Descartes has a solution to the problem of how mind and body, conceived as fundamentally distinct substances, causally interact.
Please note that the problem of how mind and body can be distinct substances yet causally interact with one another is not the Mind-Body Problem. It is a problem with Descartes' solution--so-called 'cartesian dualism or interactionism'--to the Mind-Body Problem. The Mind-Body Problem, rather, is fundamentally the puzzle of how minds and bodies require radically different, apparently mutually irreducible vocabularies to describe and study. Physics does not trade in descriptions of beliefs and desires any more than Psychology trades in descriptions of masses and momenta.
Nor is it clear that Descartes has as good a case for Dualism as it might have seemed in the first place. We considered three arguments for Dualism. I argued that the first and third depend on illegitimate uses of Leibniz Law. I also argued that Descartes' second argument for dualism is possibly unsound insofar as it assumes that the mind is indivisible. It might also be argued that 'divisible' is used in different senses in the argument. That is, bodies are divisible in the sense that they are physical objects that can be split in two, while minds are not divisible, according to the argument, into things which are also minds. Yet, following up on Plato's tripartite distinction of the soul, and considering modern psychology's distinction between the conscious and the unconscious mind, it is not so clear that the mind is quite the monolithic and indivisible entity Descartes thought it was.
Still, that Descartes' own arguments may not stand up to scrutiny does not suggest there cannot be other, better reasons for thinking the natural world is necessarily richer than we ordinarily take it to be. According to the corollary to the indiscernibility of identicals, if there is some property A has B lacks, or vice versa, then A ≠ B. Any of the aforementioned properties, either those ascribed to minds or those ascribed to bodies, will suffice to satisfy the corollary.
Alas, we did not get as far through the material as I would have liked. Next time we pick up right where we left off with Hume. From there we move on to the contemporary debates over the relationship between mind and body, where the shift away from dualism towards so-called reductive materialism or physicalism takes some curious and illuminating turns.