Although Socrates is often described as the “father of Western philosophy,” the French philosopher René Descartes* is widely considered the “founder of modern philosophy.” As profoundly insightful as such thinkers as Socrates and Plato were regarding the nature of the self, their understanding was also influenced and constrained by the consciousness of their time periods. Descartes brought an entirely new—and thoroughly modern—perspective to philosophy in general and the self in particular. Earlier philosophers had focused on exploring the fundamental questions of human existence, such as:

• What is the nature of reality?

• What is the “good life” and how we ought to behave?

• Does God exist? If so, what is God’s nature and relation to humankind?

• What is the nature of the soul?

• What is the ideal society?

Although Descartes recognized these as significant questions, he was more concerned with understanding the thinking process we use to answer questions such as these. He agreed with the great thinkers before him that the human ability to reason constitutes the extraordinary instrument we have to achieve truth and knowledge. But instead of simply using reason to try to answer questions, Descartes wanted to penetrate the nature of our reasoning process and understand its relation to the human self. He was convinced that to develop the most informed and well-grounded beliefs about human existence, we need to be clear about the thinking instrument we are employing. For if our thinking instrument is flawed, then it is likely that our conclusions will be flawed as well.

As an accomplished mathematician (he invented analytic geometry) and an aspiring scientist, Descartes was an integral part of the scientific revolution that was just beginning. (His major philosophical work, Meditations on First Philosophy, was published in 1641, the year before Galileo died and Isaac Newton was born.) The foundation of this scientific revolution was the belief that genuine knowledge needed to be based on independent rational inquiry and real-world experimentation. It was no longer appropriate to accept without question the “knowledge” handed down by authorities—as was prevalent during the religion-dominated Middle Ages. Instead, Descartes and others were convinced that we need to use our own thinking abilities to investigate, analyze, experiment, and develop our own well-reasoned conclusions, supported with compelling proof. In a passage from his Discourse on Method, Descartes contrasts the process of learning to construct knowledge by thinking independently with simply absorbing information from authorities:

But reasoning effectively does not mean simply thinking in our own personal, idiosyncratic ways: That type of commonsense thinking is likely to be seriously flawed. Instead, effective use of “the natural light of reason” entails applying scientific discipline and analytic rigor to our explorations to ensure that the conclusions that we reach have genuine merit:

One of the reasons Descartes is such an influential and enduring figure in philosophy is his willingness to test his reasoning powers to their limit and to record with absolute candor the results of his explorations. To this end, Descartes typically writes in the first person, inviting us to participate in his reasoning process and compare it with our own. He’s saying, in effect: “This is what makes sense to me—do you agree?” In his best known work, Meditations on First Philosophy, Descartes shares with us his own philosophical journal, analogous to the philosopher’s journal that you have been encouraged to keep as an integral part of this course. In an opening passage that virtually every young adult can appreciate, Descartes confesses that he has come to the conclusion that virtually everything he has been taught from authorities and other adults is questionable and likely false. His radical solution? To establish a fresh start on gaining true, well-supported beliefs by simply erasing his endorsement of anything he has previously been taught. What a bold and extraordinary project!

Descartes is convinced that committing yourself to a wholesale and systematic doubting of all things you have been taught to simply accept without question is the only way to achieve clear and well-reasoned conclusions. More important, it is the only way for you to develop beliefs that are truly yours and not someone else’s. He explains, “If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.” This sort of thoroughgoing doubting of all that you have been taught requires great personal courage, for calling into question things like your religious beliefs, cultural values, and even beliefs about your self can be, in the short term, a very disruptive enterprise. It may mean shaking up your world, questioning the beliefs of important people in your life, perhaps challenging your image of yourself. Yet there is a compelling logic to Descartes’s pronouncement: For, if you are not willing to question all that you have been asked to accept “on faith,” then you will never have the opportunity to construct a rock-solid foundation for your beliefs about the world and your personal philosophy of life. What’s more, you will never have the experience to develop the intellectual abilities and personal courage required to achieve your full potential in the future.

This, then, is the beginning of Descartes’s quest for true knowledge that leads to his famous first principle: Cogito, ergo sum—“I think, therefore I am.” We will be exploring his epistemological odyssey in some detail in the sections on Knowledge and Truth. For now, we’re going to focus on Descartes’s analysis of the self, the theme of this chapter.

Cogito, ergo sum is the first principle of Descartes’s theory of knowledge because he is confident that no rational person will doubt his or her own existence as a conscious, thinking entity—while we are aware of thinking about our self. Even if we are dreaming or hallucinating, even if our consciousness is being manipulated by some external entity, it is still my self-aware self that is dreaming, hallucinating, or being manipulated. Thus, in addition to being the first principle of his epistemology, cogito ergo, sum is also the keystone of Descartes’s concept of self. The essence of existing as a human identity is the possibility of being aware of our selves: Being self-conscious in this way is integral to having a personal identity. Conversely, it would be impossible to be self-conscious if we didn’t have a personal identity of which to be conscious. In other words, having a self-identity and being self-conscious are mutually dependent on one another. Here’s how Descartes explains this phenomenon in his Meditation II.

For Descartes, then, this is the essence of your self—you are a “thinking thing,” a dynamic identity that engages in all of those mental operations we associate with being a human self. For example:

• You understand situations in which you find yourself.

• You doubt the accuracy of ideas presented to you.

• You affirm the truth of a statement made about you.

• You deny an accusation that someone has made.

• You will yourself to complete a task you have begun.

• You refuse to follow a command that you consider to be unethical.

• You imagine a fulfilling career for yourself.

• You feel passionate emotions toward another person.

But in addition to engaging in all of these mental operations—and many other besides—your self-identity is dependent on the fact that you are capable of being aware you are engaging in these mental operations while you are engaged in them. If you were consistently not conscious of your mental operations, consistently unaware of your thinking, reasoning, and perceiving processes, then it would not be possible for you to have a self-identity, a unique essence, a you.

But what about your body? After all, a great deal of our self-concept and self-identity is tied up with our physical existence: our physical qualities, appearance, gender, race, age, height, weight, hair style, and so on. Despite this, Descartes believes that your physical body is secondary to your personal identity. One reason for this is that he believes you can conceive of yourself existing independently of your body.

Nevertheless, even though your body is not as central to your self as is your capacity to think and reflect, it clearly plays a role in your self-identity. In fact, Descartes contends, if you reflect thoughtfully, you can see that you have clear ideas of both your self as a thinking entity and your self as a physical body. And these two dimensions of your self are quite distinct.

It is at this point that we can see the pervasive influence of the metaphysical framework created by Socrates and Plato and perpetuated through the centuries by such thinkers as Plotinus and Saint Augustine. Following directly in their footsteps, Descartes declares that the essential self—the self as thinking entity—is radically different than the self as physical body. The thinking self—or soul—is a nonmaterial, immortal, conscious being, independent of the physical laws of the universe. The physical body is a material, mortal, nonthinking entity, fully governed by the physical laws of nature. What’s more, your soul and your body are independent of one another, and each can exist and function without the other. How is that possible? For example, in the case of physical death, Descartes believes (as did Plato) that your soul continues to exist, seeking union with the spiritual realm and God’s infinite and eternal mind. On the other hand, in cases in which people are sleeping or comatose, their bodies continue to function even though their minds are not thinking, much like the mechanisms of a clock.

Thus Descartes ends up with Plato’s metaphysic, a dualistic view of reality, bifurcated into

• a spiritual, nonmaterial, immortal realm that includes conscious, thinking beings, and

• a physical, material, finite realm that includes human bodies and the rest of the physical universe.

In the case of the human self, the soul (or mind) and the physical body could not be more different. For example, you can easily imagine the body being divided into various parts, whereas it is impossible to imagine your soul as anything other than an indivisible unity (precisely the point that Socrates makes when he’s arguing for the immortality of the soul):

This dualistic view of the self is particularly useful for Descartes, who was faced with a serious conflict in his personal and professional life. As previously noted, Descartes was first and foremost a scientist in his professional life, committed to establishing true knowledge through rigorous reasoning, experimentation, and analysis. Many scientists of the time—physicists, astronomers, biologists—were inclined to view the human self in terms of the physical body, governed by the same laws of physics that defined the operation of the rest of the physical universe. However, if the self is seen exclusively in terms of the physical body, the self is terminated when the body dies.

As a devout Catholic who believed in God, immortal souls, and eternal life, this view of the world was completely unacceptable to Descartes. However, by advocating a dualistic metaphysic, Descartes was able to maintain both his scientific integrity and his religious convictions. The physical self is a part of nature, governed by the physical laws of the universe, and available to scientific analysis and experimentation. At the same time, the conscious self (mind, soul) is a part of the spiritual realm, independent of the physical laws of the universe, governed only by the laws of reason and God’s will.

Although a bifurcated view of the universe solves some immediate problems for Descartes, it creates other philosophical difficulties, most notably the vexing question, “What is the relationship between the mind and the body?” In our everyday experience, our minds and bodies appear to be very closely related to one another. Our thinking and emotions have a profound effect on many aspects of our physical bodies, and physical events with our bodies have a significant impact on our mental lives. For the most part, we experience our minds and bodies as a unified entity, very different from the two different and completely independent substances that Descartes proposes. As the writer and humorist Mark Twain noted, “How come the mind gets drunk when the body does the drinking?” Even Descartes recognized the need to acknowledge the close, intimate relationship between mind and body, as the following passage reveals:

Descartes believed that the “intermingling” point of contact was through the pineal gland, a small gland located at the base of the skull. It was here that he believed that the thinking self connected to the physical brain. Why the pineal gland? Descartes found its physical location appropriate, and it had no known biological function in Descartes’s time. Ever the scientist, Descartes dissected a variety of animals to learn more about this mysterious gland.

Recognizing the problem of the mind-body relationship in a dualistic system and solving the problem in a satisfactory way are two very different things. Most philosophers agree that Descartes’s efforts to provide an integrated model of his concepts of the mind and body were not successful, and it’s a problem that has challenged thinkers in every discipline ever since. We will continue our exploration of the mind-body “problem” later in this chapter.

How did Descartes’s views regarding the self relate to his personal life? In a fascinating way: Descartes was plagued by frail health, a condition that caused him throughout his life to sleep late into the morning. A financial inheritance from his parents meant he didn’t have to work. Instead, he devoted his life to study and experimentation, spending much of his time alone, and moving from place to place on a regular basis (he lived in twenty different houses in one twenty-year period). Descartes preferred the company of himself because it provided him the opportunity to fully devote himself to his scientific, mathematical, and philosophical activities, without the distraction of social relationships (although he did find time to father an illegitimate child with a servant). Ironically, it was an error in judgment that hastened the death of his body. Against his better judgment, he accepted the invitation of Queen Christina of Sweden to come to Stockholm and tutor her. Unfortunately, the queen turned out to be an early riser, depriving Descartes of his beloved sleep. That, combined with the cold and damp climate of Stockholm, led to pneumonia and his premature death at the age of fifty-three, providing him with a firsthand opportunity to test his theory of an immortal soul.