Tuesday 1/23

The History of Cognition II: Modern Philosophy

Readings

Texts

• Descartes, "Meditations: Meditation VI"
• Hume, "An Enquiry Concerning Human Understanding", (selections)

Notes

• The Mind-Body Problem
• Cartesian Dualism
• Humean Psychology

Links

• The Checkershadow Illusion (Adelson)

Synopsis

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 bear on 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 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.

We must grant that the mind and the body appear to be very different kinds of things having very different kinds of properties. 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 chasm between the two by asserting that physical events cause mental events and mental events cause physical events. Nevertheless, mind and body are distinct substances. How, then, do they interact? 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 distinct substances, causally interact.

Nor is it clear that Descartes has a good case for Dualism 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.

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.