Psyche and Purpose

Lecture 8.  September 16 and 22.

Afterthoughts.  Aristotle is important for us in his treatment of two of the things we take for granted in psychology.  The first is the existence of a psyche, or soul, as discussed in class and in earlier posts; the second is purpose.  I remarked that positing the existence of a soul-thing would create problems for psychology, because how soul as a non-material entity interacts with the body as a material entity will prove deeply puzzling.  Aristotle’s analysis of the soul-body relationship offers a way out.  He agrees with intuition and Plato that we need to distinguish soul and body, but disagrees that we need therefore to separate soul and body.  

Plato’s postulation of transcendental Forms existing apart from their earthly copies is called the doctrine of “the separability of the Forms,” and we learned in class that Aristotle rejected it, and replaced it with his form (note the lower case) vs. matter distinction, in which form is defined as what individuates an object — defines what it is — rather than as a thing separate from matter.  Thus according to Aristotle, but not Plato, form cannot exist without embodiment.  Applied to psychology, the soul is the form of the body, and cannot exist without a body.  Moreover, his discussion of the types of soul indicates that he defines soul as biological processes, not immaterial things; for example the animal soul consists in sensation and movement.  It is important to observe that Aristotle does not say the soul carries out these functions, because that would lead to dualism.  Instead, the soul is these functions in a living body.  When life ceases, the functions, and the soul, cease, too.  

In certain respects Aristotle’s theory of the soul-body relation is similar to that of modern information-processing psychology, which says that the human mind is a set of computational functions carried out by the brain similar to the way a computer program is a set of computational functions running in a computer (mind is to body as program is to computer).  Indeed, on this “functionalist” theory of mind and body, it’s logically possible to figure out what program code constitutes your personality and then load the code into a computer, which would then be mentally identical to you (see this famous paper, “Where am I?” by philosopher Daniel Dennett: .)  In fact, some folks in AI hope to achieve immortality that way (  For a criticism of the idea that Aristotle was a functionalist, see ).

The other taken-for-granted concept, purpose, is closely linked to soul.  In saying that the soul is the form of the body, Aristotle says that soul is the final cause of the body, both the purpose for which living bodies exist (the proper end of living tissue is to perform the functions of the soul) and the giver of purposes to the body (the soul is, as it were, the body’s CEO).  As I said in class, the history of science, however, is marked by the erasure of purpose from nature, including living things and human beings.  Although Aristotle was committed to purposive explanation in all the sciences (even physics), by making purpose a concept for conscious reflection, he began its downfall.  Only when something is remarked upon can it become a topic of conversation and argument.  Aristotle began the conversation about purpose.

Forethoughts.  Christianity’s commitment to dualism meant that Aristotle’s functional definition of the soul would not catch on in European thought, even when Aristotle’s philosophy and science were assimilated into the university curricula of the high Middle Ages.  However, his treatment of the workings of the soul were accepted, but an attempt was made to see them as workings of the immortal divine soul of Plato and Christian religion.  This will soon lead, as we shall see, to two related problems.  The first is called by philosophers the homunculus [“little man”] problem.  Because the soul is the essence of who you are, it is tempting to think of the soul as a mini-you living in your head, giving the body orders.  But who is in the head of the mini-you?  a mini-mini-you?  with a mini-mini-mini-you inside, and so on absurdly ad infinitum?  A further difficulty arises when theologians and medieval natural philosophers had to identify the Christian soul with Aristotle’s rational soul (more technically, with Aristotle’s passive mind, or agent intellect, but that is not important here).  Memory is important to your personal identity; without it you would literally not know who you are.  But because memory is part of the animal sensitive soul, Christian doctrine has to exclude it from immortality.  It then follows that if only your rational soul is immortal, then you cannot have personal immortality, only immortality as pure thought without sensation, movement, or memory of your life on earth.  These issues will loom large for Descartes, arguably the most influential philosopher-psychologist of all.

Published in: on September 22, 2008 at 4:20 pm  Leave a Comment  

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