René Descartes - Biological Psychology - The Canon

Psychology: Essential Thinkers, Classic Theories, and How They Inform Your World - Andrea Bonior 2016

René Descartes
Biological Psychology
The Canon


BORN 1596, La Haye en Touraine, Kingdom of France


DIED 1650, Stockholm, Sweden


Educated at the University of Poitiers



René Descartes, whose fame is not primarily associated with psychology, made notable contributions to philosophy and mathematics. But his years of philosophizing on the nature of the mind, the scientific process, and the structures and mechanisms of the body’s actions had an indelible impact on how we think about thinking itself. Descartes is known as the originator of a thoroughly modern concept—the mind-body problem, or the question of what the mind and the body are, and of how they interact.

Cogito ergo sum—“I think, therefore I am,” a quote famous enough to be parodied on modern-day T-shirts—encompasses this towering figure’s most famous theory. That theory says this: We must abandon our thoughts about anything that can be doubted because that thing, whatever it is, is fundamentally uncertain. According to Descartes, if we were to start again from scratch, making no assumptions that could be doubted, then we would be left with just one thing—the ability to doubt. And, for Descartes, it is our very ability to doubt, and to think, that makes us conscious and true beings.

This way of thinking is probably little more than an intellectual exercise that Descartes conducted within his own mind, but it’s not hard to see its implications for the scientific method. Indeed, stripping away all assumptions before beginning an experiment is now something we see as a fundamental element of research.

Descartes is also credited with having advanced the notion of reflexes, even if certain aspects of his theory have long since been debunked and discarded. He believed that external stimuli could set off a series of events within the nerve cells that in turn would trigger the movement of what he called animal spirits. That part isn’t true, of course, but Descartes was correct—and advanced—in thinking that the body responds in automatic ways to certain external stimuli. He further posited that the interaction between awareness and bodily responses—an interaction considered to be the essence of consciousness—occurs in the brain, within the pineal gland. Descartes understood this interaction to be a two-way phenomenon, with the body influencing the mind by making the mind aware of bodily reflexes, and with the mind in turn affecting the body by initiating movement. This notion of mutual influence is at the heart of dualism, the philosophical concept of mind and body as distinct entities.

If you were to follow this idea, you would go on to assume that the mind is not physically quantifiable—that it is without concrete substance, and that thoughts have no material quality. This conceptualization of the mind also encompasses our modern definition of the soul, since Descartes believed that the mind survives bodily death. And the body, for its part, is limited and defined, according to Descartes—a physical substance through and through. This idea has a certain correspondence with the notion of primary qualities, as opposed to secondary qualities: Primary qualities—objective, observable, measurable characteristics—can be perceived apart from all subjectivity, whereas secondary qualities are not as concretely discernible and are therefore subject to bias, and to all the skewed interpretations that play a part in human perception. Similarly, Descartes distinguished between innate ideas, which he saw as springing up naturally, rather than through interaction with the outside world, and derived ideas, which he saw as born of direct external experience and of the memories formed from experience.

Notwithstanding Descartes’s rather striking thoughts about animal spirits, he believed, notably, that the pineal gland is present only in human beings, and that only human beings possess real consciousness, the ability to reason, and the capacity to feel pain. As it happens, though, the pineal gland was first discovered in an ox, and various studies have demonstrated problem-solving abilities in animals as well as the presence of painful sensations in nonhuman mammals.


The philosophy of Descartes—Cartesian philosophy, as it’s called—had a direct impact on later research into human sensation, thought, and experience. But some later theorists rejected the Cartesian conceptualization of dualism, holding instead that all experiences and things should be categorized in only one of two ways, as either material or immaterial. Thomas Hobbes understood mental processes to be caused by physical activity within the brain, and he believed that all knowledge arises from sensation; the Hobbesian view was that there are no innate ideas and everything is material. John Locke, although greatly influenced by Descartes’s mechanistic approach, rejected Cartesian dualism in favor of empiricism. Along these lines, George Berkeley (pronounced “Barkley”) and Baruch Spinoza joined Hobbes and Locke in rejecting Cartesian ideas, but discussion of the mind-body problem continues to this day.



The question of where the mind ends and the body begins, and vice versa, gained major traction with Cartesian philosophy, but of course this issue has yet to be definitively settled. We know that the mind affects the body and the body affects the mind, but at what point are they distinct entities? Is the material world real if our mind is not there to perceive it?

Some of the quirkiest party tricks are, at heart, explorations of the distinction that becomes evident between the mind and the body as reflexes overtake conscious thought. Try this: Sit with your right leg raised a few inches off the floor. Move your leg rhythmically in a circle, in a clockwise direction (that part’s important.) Now, as you’re doing that, raise your right index finger, and trace the number 6 in the air in front of you. Notice anything interesting about your right foot? It has almost certainly stopped moving clockwise, and it has probably begun to go in the opposite direction! You might ask what that foot is thinking, but this is a case of your conscious mind’s woeful inability to triumph over your body’s desperate, reflexive impulse to have both the right foot and the right finger moving in the same direction. That reflexive impulse dominates because your right foot and your right finger are both controlled by the left side, or hemisphere, of your brain, and your brain is trying to simplify things. Can you blame it? Now repeat the experiment, again moving your right leg in a clockwise circle, but this time use your left hand to trace the number 6 in the air. Now you shouldn’t see the same reflex. That’s because the two different hemispheres of your brain can work concurrently on different tasks.

Reflexes certainly do matter. Sometimes the body reacts, and the mind has trouble overriding the body, no matter what the mind’s intentions may be. We see this phenomenon when we sneeze, flinch, blink, recoil from a hot stove top, or freeze up in terror. We can thank René Descartes for being an early proponent of the notion of reflexes and for offering descriptions that have sparked study for centuries.

You may also be thinking in Cartesian terms if you’re someone who ponders the nature of the soul or the qualities of God. Some clergymen who were contemporaries of Descartes believed that his works were subversive, even heretical, but he actually had a deep religious faith. His concept that the soul and the mind are one entity, and that they transcend the material world’s constraints of time and space, is certainly one that millions of people still follow or at least think about. Is there something in the brain that rises above its physical nature, and that gives our personhood meaning beyond the trappings of this Earth? Descartes certainly thought so, but perhaps none of us can know for sure.