To be human is to be curious about ourselves and the world around us. We can trace many of psychology’s current questions back to historic philosophical and physiological approaches. These early thinkers wondered: How does our mind work? How does our body relate to our mind? How much of what we know comes built in? How much is acquired through experience?
In ancient Greece, the philosopher-teacher Socrates (469–399 B.C.E.) and his student Plato (428–348 B.C.E.) concluded that mind is separable from body and continues after the body dies, and that knowledge is innate—born within us. Unlike Socrates and Plato, who derived principles by logic, Plato’s student Aristotle (384–322 B.C.E.) loved data. An intellectual ancestor of today’s scientists, Aristotle derived principles from careful observations. Moreover, he said knowledge is not preexisting (sorry, Socrates and Plato); instead it grows from the experiences stored in our memories.
The next 2000 years brought few enduring new insights into human nature, but that changed in the 1600s, when modern science began to flourish. With it came new theories of human behavior and new versions of the ancient debates. A frail but brilliant Frenchman named René Descartes [day-CART] (1595–1650) agreed with Socrates and Plato about the existence of innate ideas and mind’s being “entirely distinct from body” and able to survive its death. Descartes’ concept of mind forced him to wonder, as people have ever since, how the immaterial mind and physical body communicate. A scientist as well as a philosopher, Descartes dissected animals and concluded that the fluid in the brain’s cavities contained “animal spirits.” These spirits, he surmised, flowed from the brain through what we call the nerves (which he thought were hollow) to the muscles, provoking movement. Memories formed as experiences opened pores in the brain into which the animal spirits also flowed.
Descartes was right that nerve paths are important and that they enable reflexes. Yet, genius though he was, and standing upon the knowledge accumulated from 99+ percent of our human history, he hardly had a clue of what today’s average 12-year-old knows. Indeed, most of the scientific story of our self-exploration—the story told in this book—has been written in but the last historical eye-blink of human time.
“ If I see further, it is by standing on the shoulders of giants.”
Isaac Newton, writing to a friend in 1676
Meanwhile, across the English Channel in Britain, science was taking a more down-to-earth form, centered on experiment, experience, and commonsense judgment. Francis Bacon (1561–1626) became one of the founders of modern science, and his influence lingers in the experiments of today’s psychological science. Bacon also was fascinated by the human mind and its failings. Anticipating what we have come to appreciate about our mind’s hunger to perceive patterns even in random events, he wrote that “the human understanding, from its peculiar nature, easily supposes a greater degree of order and equality in things than it really finds” (Novum Organuum, 1620).
Some 50 years after Bacon’s death, John Locke (1632–1704), a British political philosopher, sat down to write a one-page essay on “our own abilities” for an upcoming discussion with friends. After 20 years and hundreds of pages, Locke had completed one of history’s greatest late papers (An Essay Concerning Human Understanding). In it he famously argued that the mind at birth is a tabula rasa—a “blank slate”—on which experience writes. This idea, adding to Bacon’s ideas, helped form modern empiricism, the idea that what we know comes from experience, and that observation and experimentation enable scientific knowledge.