Story of Psychology - Morton Hunt [18]
For far from regarding sense perceptions as illusory and untrustworthy, Aristotle considered them the essential raw material of knowledge.18Extraordinary for one who had studied with Plato, he had, says one Aristotle scholar, “an intense interest in the concrete facts”;19 he regarded the direct observation of real things, except in abstract domains such as mathematics, to be the foundation of understanding. In De Generatione Animalium, for instance, after admitting that he does not know how bees procreate, he says:
The facts have not yet been sufficiently established. If ever they are, then credit must be given to observation rather than to theories, and to theories only insofar as they are confirmed by the observed facts.20
Like earlier philosophers, he sought to understand how perception takes place, but having no way to gather hard data on the matter— testing and experimentation were unknown, the dissection of human bodies impermissible—he relied on metaphysical explanations. He theorized that we do not perceive objects as such but their qualities, such as whiteness and roundness, which are nonmaterial “forms” that inhere in matter. When we see them, they are re-created within the eye, and the sensations they arouse are transmitted through the blood vessels to the mind—which, he thought, must be in the heart, since people often recover from injuries to the head while wounds to the heart are invariably fatal. (The brain’s function, he thought, was to cool the blood when it became overly warm.) He also discussed the possible existence of an interior sense, the “common” sense, by means of which we recognize that various sensations arriving from different sense organs—say, white and round, warm and soft—come from a single object (in this case, a ball of wool).
If we ignore these absurdities, Aristotle’s explanation of how perceptions become knowledge is commonsensical and convincing, and complementary to the perception-based epistemologies of Protagoras and Democritus. Our minds, Aristotle says, recognize the similarities in a series of objects—this is the essence of inductive reasoning—and from those common traits form a “universal,” a word or concept signifying not an actual thing but a sort of thing or a general principle; this is the route to higher levels of knowledge and wisdom. Reason or intellect thus acts upon sense data; it is an active, organizing force.
Having spent so many years examining biological specimens, Aristotle was of no mind to regard the objects of perception as mere illusions, or to rank generalized concepts as more real than the individual things they summarize. Where Plato said that abstract ideas exist eternally, apart from material things, and are more real than they, his realistic pupil said they were only attributes that could be “predicated” of specific subjects. Though he never totally abandoned the metaphysical trappings of Greek thought, he came close to saying that universals have no existence except in the thinking mind. He thus synthesized the two main streams of Greek thinking about knowledge: the extreme emphasis on sense perception of Protagoras and Democritus and the extreme rationalism of Socrates and Plato.
About the relation of mind to body, at times he is hopelessly opaque, at other times crystal clear. The opacity concerns the nature of “soul,” which, waxing metaphysical, he calls the “form” of the body—not its shape but its “essence,” its individuality, or perhaps its capacity to live. This muddy concept was to roil the waters of psychology for many centuries.
On the other hand, his comments about that part of the soul where thinking takes place are lucid and sensible. “Certain writers,” he says in De Anima, “have happily called the soul the place of ideas, but this description applies not to the soul as a whole but merely to the power of thought.”21 Most of the time he calls the part of the soul where thinking takes place the psyche, although sometimes he uses that