Aristotle's Contribution to Learning & Behavior
Aristotle, who lived and taught in Greece around 350 B.C., contributed several basic ideas relating to learning and behavior that reappear many centuries later to influence the development of Psychology. These include Aristotle's conception of the life-force, "psyche," or "soul" that distinguishes the animate from the inanimate, his elucidation of the four "causes," and his ideas about the factors involved in memory.
The Three Souls
The ancient Greeks, including Aristotle, were puzzled by the obvious differences between living and nonliving things and sought to account for these differences. They were hampered in this endeavor by an inadequate understanding of chemistry and physiology; for example, they had no idea that the function breathing is to bring oxygen into the lungs and carry off carbon dioxide. Living things seemed to "have" something that nonliving things lacked, an animating principle which the Greeks called the "psyche," a term that has usually been translated into english as "soul." A living human being breathed and was warm; a dead one did not breathe and was cold. It seemed logical to conclude that the human psyche had something to do with warmth and breath. The dead were cold and did not breathe because their psyches had left them.
Aristotle elaborated on this basic theme by suggesting that different types of living things have different kinds of psyche, which confer on them different properties or abilities. Plants could take in nourishment, grow, and reproduce themselves, so Aristotle suggested that they possessed a "nutritive" or "vegetative" soul which conferred these abilities upon them. Animals could also take in nourishment, grow and reproduce, but in addition they had the power to sense and to move. These powers were conferred upon the animal by its "sensitive" soul. Finally, human beings could do everything plants and animals could do (take in nourishment, grow, reproduce, sense, move) but in addition had the power to think, to reason. Humans must therefore have a different, more capable soul than other animals, which Aristotle termed the "rational soul."
Possession of these different psyches or souls is used to explain the different abilities of plants, animals, and human beings, but as the explanation stands it is circular. Why does a human being have the ability to reason? Because humans have a rational soul. How do we know that humans have a rational soul? Because they are able to reason. We are given no reason to believe in the existence of these different souls other than the differences in ability that the different souls were invented to explain. Aristotle's labels do serve, however, to identify what he believed were the basic functional differences between plants, animals, and human beings.
The Four Causes
Aristotle distinguished among four causes, or reasons why something is as it is: efficient, formal, material, and final. Efficient causation is what we would today refer to as mechanical causation, or cause and effect. Formal causation refers to the form something takes -- a statue of Atlas is a statue of Atlas rather than a marble table because of its form. Material causation refers to the material out of which something is made -- a statue of marble is brittle because it is made from marble rather than bronze. Finally, final causation refers to the end for which something exists. For example, wings exist for the purpose of flight.
Our interest here is in the first and last of Aristotle's four causes -- efficient causation and final causation. Efficient causation is at the heart of modern explanations of phenomena. Such causes precede their effects and constitute the explanation for those effects. Example: Thunder is caused by the explosive expansion of air heated by a large, sudden flow of electricity through it, which produces vibrations in the air that we perceive as thunder. Although Aristotle's principle of efficient causation is accepted today, his principle of final causation has often been misunderstood and rejected as unscientific. It has been confused with the notion that the end somehow brings about its own means. This idea would have it that a bird has wings because it needs them to fly. Somehow the need to fly causes wings to develop. That sort of idea is properly rejected as unscientific, but it was not Aristotle's conception of final causation. Rather, Aristotle is saying that, to understand why something has certain properties, one must know what function or functions it serves for its possessor:
Our knowledge [of such structures] must come from a study of their functions." [De Partibus Animalium II, ch. 9: 655b 21.]For example, to understand why the heart has the structure it does, one must know what the heart does: it pumps blood. Today we would say that "form follows function." Aristotle views these functions in terms of their contribution to the survival of the organism:
A being which has no sensation when it comes into contact with other things will be unable to avoid some and seize others. And if this is so, it will be impossible for the animal to survive. [De Anima III]
Aristotle had no concept of evolution, but over 2,000 years later Charles Darwin would propose a theory of the evolution of species that would at last explain how organisms come to have just those parts whose functions enable them to survive and reproduce.
Another topic on which Aristotle wrote that is of interest to us in the study of learning and behavior concerns how people are able to recall things. He suggested that the recollection or observance of one thing will tend to facilitate the recall of another according to three basic principles: contiguity, similarity, and contrast. According to the principle of contiguity, one idea will tend to bring to mind another when the two have in the past been experienced together (contiguity refers to "togetherness" in space or time). The similarity principle states that one thing will tend to facilitate recall of another to the extent that the two are similar. Thus, on viewing a beautiful sunset you may suddenly recall the scene of another day when you witnessed a similarly beautiful sunset. Finally, the principle of contrast states that thinking of one thing tends to bring to mind its opposite, as when thinking of hot reminds you of cold. Two thousand years after Aristotle, these principles would resurface as keys to learning under the process of association.