The Story of Psychology (4 page)

Their general answer was sense experience. Alcmaeon, for one, said that the sense organs send perceptions to the brain, where, by means of thinking, we interpret them and derive ideas from them. What intrigued him and others was how the perceptions get from the sense organs to the brain. Unaware of nerve impulses, even though he had discovered the optic nerve, and believing, on abstract metaphysical grounds, that air was the vital component of mind, he decided that perceptions must
travel along air channels from the sense organs to the brain: No matter that he never saw any and that no such channels exist; reason told him it must be so. (Later Greek anatomists would refer to the air,
pneuma
, they thought was in the nerves and brain as “animal spirits,” and in one form or another this belief would dominate thinking about the nervous system until the eighteenth century.) Although Alcmaeon’s theory was wholly incorrect, his emphasis on perception as the source of knowledge was the beginning of epistemology—the study of how we acquire knowledge—and laid the ground for a debate about that topic that has gone on ever since.

Alcmaeon’s ideas were borne around the far-flung Greek cities by travelers; soon, philosophers in many places were devising their own explanations of how perception takes place, and a number of them asserted that it was the basis of all knowledge. But some saw the troubling implications of this view. Protagoras (485–411), best known of the Sophists (a term that then meant not fallacious reasoners but “teachers of wisdom”), unsettled his contemporaries and pupils by pointing out that, since perception was the only source of knowledge, there could be no absolute truth. His famous apothegm, “Man is the measure of all things,” meant, he explained, that any given thing is to me what it appears to me to be, and, if it appears different to you, is what it seems to you to be. Each perception is true—for each perceiver. Philosophers were willing to debate the point, but politicians considered it subversive. When Protagoras, visiting Athens, tactlessly applied his theory to religion, saying there was no way for him to know whether the gods exist or not, the outraged Assembly banished him and burned his writings. He fled and drowned at sea en route to Sicily.

Others carried on that line of inquiry, devising explanations of how perception takes place and maintaining that, since knowledge is based on perception, all truths are relative and subjective. The most sophisticated of such musings were those of Democritus (460–362) of Abdera, Thrace, the most learned man of his time. Vastly amused by the follies of humankind, he was known as the “laughing philosopher.” His main claim to fame, actually, derives not from his psychological reflections
but from his extraordinary guess that all matter is composed of invisible particles (atoms) of different shapes linked together in different combinations, a conclusion he came to, without any experimental evidence, by sheer reasoning. Unlike Alcmaeon’s air channels, this theory would eventually be proven absolutely correct.

From his theory of atoms Democritus derived an explanation of perception. Every object gives off or imprints on the atoms of the air images of itself, which travel through the air, reach the eye of the beholder, and there interact with its atoms. The product of that interaction passes to the mind and, in turn, interacts with its atoms.
³
He thus anticipated, albeit in largely incorrect detail, today’s theory of vision, which holds that photons of light, emanating from an object, travel to the eye, enter it, and stimulate the endings of the optic nerves, which send messages to the brain, where they act on the brain’s neurons.

All knowledge, according to Democritus, results from the interaction of the transmitted images with the mind. Like Protagoras, he concluded that this means we have no way of knowing whether our perceptions correctly represent what is outside or whether anyone else’s perception is identical with our own. As he put it, “We know nothing for certain, but only the changes produced in our body by the forces that impinge upon it.”
⁴
That issue would vex philosophers and psychologists from then until now, driving many of them to devise elaborate theories in the effort to escape the solipsistic trap and to affirm that there is some way to know what is really true about the world.

When the early philosopher-psychologists concluded that thought occurs in the mind, it was only natural that they would also wonder why our thoughts are sometimes clear and sometimes muddled, and why most of us are mentally healthy but others are mentally ill.

Unlike their ancestors, who had believed mental dysfunction to be the work of gods or demons, they sought naturalistic answers. The most widely accepted of these was that of Hippocrates (460–377), the Father of Medicine. The son of a physician, he was born on the Greek island of Cos off the coast of what is today Turkey. He studied and practiced there, treating many of the invalids and tourists who came for the island’s hot springs and achieving such renown that far-off rulers sought him out. In 430 Athens sent for him when a plague was ravaging the city; observing that blacksmiths seemed immune to it, he ordered fires
built in all public squares and, legend says, brought the disease under control. Only a handful of the seventy-odd tracts bearing his name were actually written by him, but the rest, the work of his followers, embody his ideas, which are a mixture of the sound and the absurd. For instance, he stressed diet and exercise rather than drugs, but for many diseases recommended fasting on the grounds that the more we nourish unhealthy bodies, the more we injure them.

His greatest contribution was to divorce medicine from religion and superstition. He maintained that all diseases, rather than being the work of the gods, have natural causes. In this spirit, he taught that most of the physical and mental ills of his patients had a biochemical basis (though the term “biochemical” would have meant nothing to him).

He based this explanation of health and illness on the prevailing theory of matter. Philosophers had held that the primordial stuff of the world was water, fire, air, and so on, but Empedocles concocted a more intellectually satisfying theory, which dominated Greek and later thinking. All things, he said, are made up of four “elements”—earth, air, fire, and water—held together in varying proportions by a force he called “love” or kept asunder by its opposite, “strife.”
⁵
Though the specifics were wholly wrong, many centuries later scientists would find that his core concept—that all matter is composed of elemental substances alone or in combination—was quite right.

Hippocrates borrowed Empedocles’ four-element theory and applied it to the body. Good health, he said, is the result of a proper balance of the four bodily fluids, or “humors,” which correspond to the four elements—blood corresponding to fire, phlegm to water, black bile to earth, and yellow bile to air. For the next two thousand years physicians would attribute many illnesses to humoral imbalances that they would try to cure by draining off an excess of a humor (as in bloodletting) or by administering medicines supplying one that was lacking. The harm this caused over the centuries, particularly through bloodletting, is incalculable.

Hippocrates used the same theory to explain mental health and illness. If the four humors were in proper balance, consciousness and thought would function well, but if any humor was either in excess or short supply, mental illness of one kind or another would result. As he wrote:

Later, followers of Hippocrates extended his humoral theory to account for differences in temperament. Galen, in the second century
A.D.
, said that a phlegmatic person suffers from an excess of phlegm, a choleric one from an excess of yellow bile, a melancholic one from an excess of black bile, and a sanguine one from an excess of blood. That doctrine persisted in Western psychology until the eighteenth century and remains embedded in our daily speech—we call people “phlegmatic,” “bilious,” and so on—if not our psychology.

Although the humoral theory of personality and of mental illness now seems as benighted as the belief that the earth is the center of the universe, its premise—that there is a biological basis to, or at least a biological component in, personality traits and mental health or illness—has lately been confirmed beyond all question. A vast amount of recent research by cognitive neuroscientists has identified many of the substances produced by brain cells and shown how these enable thought processes to take place, and myriad other studies have shown that foreign substances such as drugs or toxins distort or interfere with those processes. Hippocrates was close to the mark after all.

One can only marvel at the psychological musings of Hippocrates and the pre-Socratic psychophilosophers. Quite without laboratories, methodology, or empirical evidence—indeed, without anything but open minds and intense curiosity—they recognized and enunciated a number of the salient issues and devised certain of the theories that have remained central in psychology from their time to our own.

We now come upon a man unlike the shadowy figures we just met, a real and vivid person whose appearance, personal habits, and thoughts are thoroughly documented: Socrates (469–399), the leading philosopher of his time and the proponent of a theory of knowledge that directly contradicted perception-based theory. We know a good deal about him as a person because two of his pupils—Plato and the historian-soldier Xenophon—set down detailed recollections of him. Unfortunately, Socrates himself wrote nothing, and his ideas come to us chiefly through Plato’s dialogues, where much of what he says is probably Plato’s own thinking put in Socrates’ mouth for dramatic reasons. Nonetheless, Socrates’ contributions to psychology are clear.

He lived during the first half of Athens’ era of greatness (the span from its defeat of the Persians at Salamis in 480 to the death of Alexander in 323), when philosophy and the arts flourished as never before. The son of a sculptor and a midwife, he was fascinated by what he learned of philosophy in his youth from Protagoras, Zeno of Elea, and others. He early decided to make it his life work, but, unlike the Sophists, he took no fees for his teaching; he would talk to anyone who wanted to discuss ideas with him. He occasionally worked as a stonecutter and carver of statues but preferred the luxury of thought and discourse to the comforts money could buy. Content to be poor, he wore one simple shabby robe all year and went barefoot; once, looking about in the marketplace, he exclaimed with pleasure, “How many things there are that I do not want!”

Not that he was an ascetic; he liked good company, sometimes went to banquets given by the wealthy, and freely confessed to feeling a “flame” within him when he peered inside a youth’s garment. Uncommonly homely, with a considerable paunch, a bald head, broad snub nose, and thick lips, he looked like a satyr, his friend Alcibiades told him. Unlike a satyr, however, he was a model of moderation and self-control; he seldom drank wine, remained sober when he did, and was chaste even when in love. The beautiful and amoral Alcibiades, slipping into Socrates’ bed one night to seduce him, was astonished to be treated as if by a father. “I thought I had been disgraced,” he later said, according to Plato’s
Symposium
, “and yet I admired the way this man was made, and his temperance and courage.”

Socrates kept himself in good physical condition; he fought bravely during the Peloponnesian War, where his ability to withstand cold and
hunger amazed his fellow soldiers. After long years of instructing his pupils, he was tried and condemned for his teachings, which Athenian democrats said corrupted youth. The real problem was that he was contemptuous of their democracy and numbered many aristocrats, their political foes, among his followers. He accepted the verdict with equanimity and refused the opportunity to escape, preferring to die with dignity.

Although the Delphic Oracle once declared Socrates the wisest man in the world, he disputed that pronouncement; it was his style to claim that he knew nothing and was wiser than others only in knowing that he knew nothing. He claimed to be a “midwife of thought,” one who merely helped others give birth to their ideas. This, of course, was a pose; in reality he had a number of firmly held opinions about certain philosophic matters. But unlike many of his contemporaries, he was uninterested in cosmology, physics, or perception; as he says in Plato’s
Apology
, “I have nothing to do with physical speculations.” His concern, rather, was with ethics. His goal was to help others lead the virtuous life, which, he said, comes about through knowledge, since no man sins wittingly.

To help his students attain knowledge, Socrates relied not on lectures but on a wholly different educational method. He asked his students questions that seemingly led them step by step to discover the truth for themselves. This technique, known as dialectic, was first used by Zeno, from whom he may have learned it, but it was Socrates who developed and popularized it. In doing so, he promulgated a theory of knowledge that would be the major alternative to perception-based theories from then on.