Chapter 4 – Foundations for a Moral Code: Rationalism and Its Flaws

In Western philosophy, rationalism is the main alternative to empiricism for describing the human mind and for modeling what knowing is. It is the way of Plato in Classical Greek times and of Descartes in the Enlightenment. Rationalism suggests that the human mind can build a system for understanding itself and for how it knows its universe, only if that system is first of all grounded in the human mind by itself, before any sensory experiences or memories of them enter the thinking system.

                                            

Descartes, for example, points out that our senses give us information that can easily be faulty. As was noted above, the stick in the pond looks bent at the water line, but if we remove it, we see it is straight. The hand on the pocket warmer and the hand in the snow can both be immersed a bit later in tepid tap water; to one hand, the tap water is cold and to the other, it is warm. And these are the simple examples. Life contains many much more difficult ones. Therefore, the rationalists say, if we want to think about thinking in rigorously logical ways, we must try to construct a system for modelling human thinking by beginning from some concepts that are built into the mind itself before any unreliable sense data or memories of sense data even enter the picture.

Plato says we come into the world at birth already dimly knowing some perfect “forms” that we then use to organize our thoughts. He drew the conclusion that these useful forms, which enable us to make sense of our world, are imperfect copies of the perfect forms that exist in a perfect dimension of pure thought, before birth, beyond matter, space, and time—a dimension of pure ideas. The material world and the things in it are only poor copies of that other world of pure forms ultimately derived from the pure Good. The whole point of our existence, for Plato, is to discipline the mind by study until we learn to more clearly recall, understand, and live by the perfect forms—perfect tools, perfect cooking, perfect medicine, perfect beauty, perfect justice, perfect animals, and many others.

Descartes formulated a similar system of thought that begins from the truth the mind finds inside itself when it carefully and quietly contemplates just itself. During this quiet and totally concentrated self-contemplation, the thing that is most deeply you, namely your mind, realizes that whatever else you may be mistaken about, you can’t be mistaken about the fact that you exist; you must exist in some way in some dimension in order for you to be thinking about whether you exist. For Descartes, this was a starting point that enabled him to build a whole system of thinking and knowing that sets up two realms: a realm of things the mind deals with through the physical body attached to it, and another realm the mind deals with by pure thinking, a realm built on “clear and distinct ideas” (Descartes’s words) that the mind knows before it ever takes in the impressions coming from the physical senses.

These two rationalists have had millions of followers—in Descartes’s case for four hundred years and in Plato’s case for well over two thousand. They have attacked empiricism for as long as it has been around (since the 1700s, or in a simpler form, some argue, since the time of Aristotle, who was Plato’s pupil, but who disagreed diametrically with Plato on several matters).