The Cartesian Paradigm

Lecture 12.  October 2 and 8.

Afterthoughts.  I talked about a Cartesian Paradigm, or Framework, that would guide scientific psychology for much of the twentieth century.  Here I want to amplify two aspects of the paradigm that will be especially important and trouble-making as we move through the rest of the course.

The first aspect is Descartes’ consideration of the mind-body problem and his particular solution to it, interactive dualism.  Most people share an intuition that there is something unique about people that sets us off from things and from the other animals, and we have seen how the Greek philosophers articulated this intuition in different ways.  However, Cartesian dualism is different from Greek dualisms, especially Aristotle’s, in important ways, and I want to stress here how Descartes’ situation is different from Aristotle’s (or all premodern thinkers) not so much because of his conception of mind or soul, but because of the new conception of matter as machine ushered in by the Scientific Revolution.

The key distinction for Descartes is between the soul and the machine-body, but for Aristotle (and the Bronze Age Greeks, too) the key distinction to be drawn was between the living and the nonliving.  For Aristotle, soul was the presence of life, in plants, animals, and humans alike.  The soul was not a thing apart from the living body, but defined the essence of each kind of creature, animated it, and gave it purpose: Soul was form, body was matter.  Soul was life-process, and what distinguished each grade of soul were the processes unique to it: animals had sensation and movement, to which humans added the ability to formulate universal truths.

Descartes, however, had to jettison the idea that plants and animals had souls, because in Christian thought only humans have souls, and he came to regard all physical things, including plant, animal, and human bodies, as machines whose various movements could be explained in the same mechanical terms as the movements of a clock or of the new Newtonian clock-universe.  For Aristotle on the one side there was unformed, unanimated matter and on the other was defining, change-giving form, or soul; for Descartes, on one side were machines, capable of motions of their own, having mechanical causes, and on the other was disembodied nonphysical soul.  Animal behavior had mechanical causes, as seemed clear from Vaucanson’s Duck and other clever automata.  Most importantly, animals had internal cognitive-mechanical processes too, responsible for sensation, awareness, imagination, memory, and learning, things traditionally associated with soul.  But for Descartes, these were no longer life-processes of the soul, as for Aristotle, but mechanical processes of the presumed reflexive gears, springs, and wheels of the nervous system and brain.  Soul was limited to one arena, consciousness, and found in only kind of creature, human beings.

The second critical aspect of the Cartesian Paradigm was the creation of the private realm of consciousness that flowed from the new scientific withdrawal of soul from the material world.  Ideas existed in consciousness only (and animals did not and could not) have them.  Because there seemed to be a New World of consciousness, it invited exploration and study with a special tool for making the voyage, introspection.  Thus was created the idea of a science devoted to consciousness, psyche-logos, the science of the soul.

Forethoughts.  We will soon see the problems raised by this new definition of human science; indeed, we have already met one in Princess Elizabeth’s observations about the difficulties of claiming that a machine can act on spirit and spirit on a machine, the problem of interaction.  What I want to point out here is a more basic problem for psychology defined according to the Cartesian framework: It makes doing psychology as a science nearly impossible, especially as science, especially physiology advances, and as the enterprise of science itself becomes more precisely formed in the nineteenth century.  

So little is left to soul in the Cartesian view that it will become tempting to simply eliminate the concept altogether and say that men are machines as are all animals, albeit more complicated ones.  If one takes this step, then since there is no psyche there can be no psyche-logos anymore then there can be Zeus-logos.  

On the other hand, if one retains the idea of consciousness, other problems arise.  If consciousness is real, but does not interact with body (the view of psycho-physical parallelism we’ll soon meet), then one can have a disciplined study of consciousness, but its point becomes unclear, especially when science is linked to application.  If consciousness exists but does not do anything, its study can have little, if any, practical pay-off.  In addition, introspection is necessarily a private exploration of one person’s consciousness, and even if it’s done in a lab with the best intentions and the tightest methodological controls, the resulting data are tainted with subjectivity, including the possibility of individual differences, the powers of suggestion and expectation, and the difficulties of verifying the accuracy of introspective reports.  While disputes of course arise in any science over the validity of data, the data of introspection will seem especially dodgy, and the enterprise of psyche-logos, while logically possible, will seem to many not to be worth the effort.

Note that these problems would not have arisen for an Aristotelean psyche-logos, because in Aristotle there is no private world of non-physical ideas populating a non-physical soul.  There is, of course, experience in Aristotle’s psychology, but experience is the process of sensation and perception; it is not the collective set of ideas present at some moment in consciousness.  There are no ideas needing description and reduction to lawful order.

That is why my last slide on Descartes said that while he invited the creation of psyche-logos, he made its practice impossible, even paradoxical.