Thursday 1/23

The History of Cognition I: Ancient Philosophy





Recall our project for the semester. We have assumed Dretske's Dictum:

You don't understand it if you don't know how to build it.

where 'it', in our case, refers to the mind. To be sure, this dictum requires us to take something like an engineering perspective, and it requires careful qualification. Here is what Dretske himself says about it.

There are things I believe that I cannot say - at least not in such a way that they come out true. The title of this essay is a case in point. I really do believe that, in the relevant sense of all the relevant words, if you can't make one, you don't know how it works. The trouble is I do not know how to specify the relevant sense of all the relevant words.

I know, for instance, that you can understand how something works and, for a variety of reasons, still not be able to build one. The raw materials are not available. You cannot afford them. You are too clumsy or not strong enough. The police will not let you.

I also know that you may be able to make one and still not know how it works. You do not know how the parts work. I can solder a snaggle to a radzak, and this is all it takes to make a gizmo, but if I do not know what snaggles and radzaks are, or how they work, making one is not going to tell me much about what a gizmo is. My son once assembled a television set from a kit by carefully following the instruction manual. Understanding next to nothing about electricity, though, assembling one gave him no idea of how television worked.

I am not, however, suggesting that being able to build one is sufficient for knowing how it works. Only necessary. And I do not much care about whether you can actually put one together. It is enough if you know how one is put together. But, as I said, I do not know how to make all the right qualifications. So I will not try. All I mean to suggest by my provocative title is something about the spirit of philosophical naturalism. It is motivated by a constructivist's model of understanding. It embodies something like an engineer's ideal, a designer's vision, of what it takes to really know how something works. You need a blueprint, a recipe, an instruction manual, a program. This goes for the mind as well as any other contraption. If you want to know what intelligence is, or what it takes to have a thought, you need a recipe for creating intelligence or assembling a thought (or a thinker of thoughts) out of parts you already understand.

-Fred Dretske, “If You Can't Make One, You Don't Know How It Works”

Perhaps we will discover that Dretske's Dictum places too great a burden on our investigations and so close the semester by rejecting it. Nevertheless, it is a good place to start, and it puts us in exactly the right frame of mind to understand the endeavors of Cognitive Science today.

Yet it is useful to begin our study of the mind from the perspective of Dretske's Dictum if we first consider what has previously been said about the mind. Hence we begin the semester with a very short survey of the history of the philosophy of mind. Today we considered Ancient views of the mind as discussed in Plato and Aristotle.

Now recall the question I asked last time, what is the most remarkable thing to be found on the beach? I suggested 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.

This important point was not lost on the Ancient Philosophers. Certainly understanding the mind and its place in nature was of central interest to both Plato and Aristotle. Moreover, they came to develop distinct positions which set the course for two very different traditions in philosophy.

Please note that our discussion of all these views is hasty almost to the point of scholarly irresponsibility. All of the philosophers we will be considering have carefully worked-out theories and arguments any one of which would require an entire semester's work to fully appreciate. We can, however, get a sense of the overall framework each philosopher has developed, and that will be enough to ground our subsequent study of contemporary issues in the foundations of cognitive science and artificial intelligence. So, whatever you do, do not come away from these views thinking them ridiculous or absurd. Any perceived silliness is surely an artifact of our brevity in considering them.

First for our consideration is Plato's complicated view of the mind. To understand the portion of the reading you were given, it is useful to understand Plato's project in the Republic. The Republic consists of a lengthy, involved, and sometimes heated discussion between Socrates and his friends on the nature of justice or morality. The question that preoccupies the Republic is, why be moral if there were no consequences to being immoral? To answer this question, Socrates proposes that the state be viewed as the individual person writ large. If we can understand why it is good for the state to be just or moral, then we can understand by analogy why it is good for individual to be just or moral. Socrates is busy explaining all this, and thereby explaining his famous tripartite distinction of the soul in your reading.

To understand Plato's tripartite division of the soul, it may help to draw on the analogy Plato uses in another dialogue, the Phaedrus. According to Plato, the human mind is composed of three parts which are akin to two horses drawing a charioteer. One of the horses is driven by its desire for food, the other is high-spirited and driven by its emotions, while the charioteer is put in the position of having to control the two unruly, uncooperative animals. What this boils down to is the proposal that the human mind or soul has three distinct parts:

  1. The Rational Soul
  2. The Passionate Soul
  3. The Appetitive Soul

No one of these parts is intrinsically bad. Rather, evil arises when the Rational Soul cedes primacy to either the Passionate Soul or the Appetitive Soul. The just or moral soul, exactly analogous to the just or moral state, is the well-ordered soul (or state).

Thus Plato is able to explain the complexity of human behavior in terms of a kind of complexity in the human mind. As we shall find, this approach to explanation is a forebear to much of current psychological explanation. Indeed, even Freud, it was noted, employs a similar tripartite distinction of the human mind in his discussions.

Is the platonic/freudian approach to explaining the mind satisfactory, though? This is where our discussion got very interesting. The point I tried to make in class is that if we conceive of the Appetitive Soul, the Rational Soul, and the Passionate Soul (or the Id, Ego, and Superego, respectively) as minds themselves--and there is no reason whatsoever to think either Plato or Freud saw them as anything else--then we must conclude that these cannot be satisfactory explanations. After all, we are being asked to accept an explanation of the mind which uses minds in the explanation. It's an altogether pointless circularity, from the standpoint of needing an explanation.

This problem raises, I submit, a fascinating question: In what terms, then, shall an explanation of mind be given?

Our ordinary folk-psychological approach is to explain minds by citing the beliefs, desires, and intentions that presumably comprise them. In doing so, we construct a theory of mind for those whose behavior we are attempting to understanding--including, notably, ourselves!

Yet as fodder for proper scientific investigation, mental states like beliefs, desires, and intentions seem spectacularly ill-suited. How, for example, does one measure them? Where are they located? How are they individuated (identified) in the first place?

Theory of Mind, which we all employ in understanding one another, seems not to fit the standard reductionist approach in the sciences to showing how a natural phenomenon in question can be boiled down, as it were, to physics. That is, if our difficulty is in just how to give a naturalistic explanation of the phenomenon of mind, it seems pointless to turn around and invoke phenomena like believing, desiring, and intending which appear at least as mysterious from the naturalist's standpoint as the mind they are intended to help us explain.

Perhaps, then, we should eschew mental states per se in favor of neurological states. This gets us much closer to the overall project of today's cognitive science, but as we shall see, we've many hurdles to cross before we get there.

Returning to the ancients, it bears noting as we did not in class as clearly as I would have liked that Plato's discussion of the soul is interwoven with epistemic worries about the nature of human knowledge and metaphysical worries about the underlying nature of reality. That is, it is only by the use of reason that man is able to apprehend the eternal and unchanging perfection of the realm of forms which underlies the messy and changing reality we actually perceive. (Put that way, Plato has a very different idea than us of what counts as a good explanation!)

Reading Plato is always a pleasure, but where Plato may be best appreciated by those with a literary and humanist bent, Aristotle often appeals to those with a more scientific attitude. For Aristotle is especially interested in developing principled classifications by which all things can be distinguished. For example, in De Anima, or On the Soul, Aristotle notes that all living things are to be distinguished from inanimate things insofar as that which lives takes nutrition, grows, dies, and decays. Thus plants, animals, and humans are to be distinguished from rocks by having a nutritive soul. Animals and humans are distinguished from plants by having appetitive, perceptive, and locomotive souls in varying degrees. Humans are distinguished from animals in having also rational souls. There is, it must be admitted, a certain elegance to this explanation. We have at least an account of a kind of fundamental hierarchy into which all organisms fall.

As with Plato, though, Aristotle considers mankind to occupy the apex of this hierarchy.

Next time we will take up Descartes, who inherits Plato's inclination to see the gap between me and the rock as profound and unbridgeable, but who also brings to bear vastly more sophisticated arguments in favor of the position.