Читать книгу Figure It Out - Stephen P. Anderson - Страница 18

Since the days of Socrates and Plato, and almost certainly before then, human beings have wondered how we think, understand, and gain knowledge about the world we inhabit. The modern quest for a theory of mind began with the emergence of cognitive science in the late 1950s. Back then, the dominant theory was behaviorism, which viewed the brain as a black box—a biological device whose inner workings could never be directly observed. Because there was no way to see an idea, or a thought, or anything that happened in the head, behaviorists were taught “to eschew such topics as mind, thinking, or imagination and such concepts as plans, desires, or intentions.”⁵ What happened in the brain was mysterious and unknowable and, therefore, off limits.

Not everyone was convinced. Some researchers believed that clever experiments could be devised that would explain the machinery of mind, at least in part. Early experiments were promising, many more were undertaken, and the cognitive revolution was underway. By the 1990s, cognitive science had convincingly demolished the central premise of behaviorism: the machinery of mind was knowable. Harvard psychologist Steven Pinker summarized the cognitive turn this way: “Behaviorists insisted that all talk about mental events was sterile speculation ... Exactly the opposite turned out to be true.”⁶

Cognitive science came to see the mind as an elaborate biological apparatus for processing information. It starts with your senses, which perceive information from the world and send signals to your brain. When you stub your toe, for example, information passes from the nerve ending, through the spinal cord, and up to your brain. When the stoplight turns green, your eyes perceive this change and send the information along the optic nerve. Your brain takes these signals and converts them into symbols. Cognitive scientists call these symbols mental representations, which is simply a scientific phrase that means thoughts or ideas. The brain processes these representations, transforming them into other representations, and the whole operation is what we call cognition. Originally known as the information-processing theory, today it is often called the computational theory of mind.

Thus, cognitive science is based on two fundamental concepts: mental representation and mental computation. The term computation, however, requires some qualification. To say the mind does computation does not mean the neurons in your brain work just like the silicon transistors in your laptop. Rather, it means that we can explain how brains and computers operate using many of the same principles, even though the details are vastly different. Pinker provides a useful analogy: “To explain how birds fly, we invoke principles of lift and drag and fluid mechanics that also explain how airplanes fly. That does not commit us to an airplane metaphor for birds, complete with jet engines and complimentary beverage service.”⁷ This view of the mind does, however, hinge on the conviction that brains do perform computation, in some way, on mental representations.