On doubt and the nature of the self

This week, I’m sharing my final essay of the semester for my Master’s program. It’s about René Descartes’s Meditations on First Philosophy.

Since the essay is a textual analysis that may be confusing without some prior knowledge of the book, here’s a summary:

Descartes's Meditations on First Philosophy, first published in 1641, is a seminal work in Western philosophy that uses a method of systematic doubt to establish a new foundation for knowledge. Through six meditations, Descartes questions everything that can be doubted to arrive at indisputable truths, most famously expressed as "Cogito, ergo sum" ("I think, therefore I am"). His exploration not only delves into the nature of the human mind and reality but also sets the stage for discussions on the relationship between the mind, body, and the physical world, profoundly shaping subsequent intellectual discourse. In my paper, I focus on the first and second meditations, particularly his conception of the self.

Side note: Descartes doesn't actually use the phrase "I think, therefore I am" in this work. But he does say something similar, albeit not as memorable, which you'll see below.

Descartes begins his Meditations by acknowledging the numerous falsehoods he has believed throughout his life and the implied invalidity of all the beliefs formed on these shaky grounds. He then introduces his method of doubt—a cornerstone in his quest for certainty:

I realized that it was necessary, once in the course of my life, to demolish everything completely and start again from the foundations if I wanted to establish anything at all in the sciences that was stable and likely to last.

Using this method, he investigates the limits of skepticism, peeling away layers of unsteady beliefs until he identifies what he considers an undeniable truth about the self.

What does Descartes’s method of doubt reveal about the nature of the self in the first and second meditation?

Initiation of the method of doubt

In his attempt to “demolish everything” as swiftly as possible, Descartes formulates the following approach:

Reason now leads me to think that I should hold back my assent from opinions which are not completely certain and indubitable just as carefully as I do from those which are patently false.

If there's even the slightest possibility of doubt, Descartes will consider it as false. He has committed himself to starting fresh from a blank slate. This radical skepticism serves as a catalyst for a deeper inquiry into the self. At this point, Descartes has not yet concluded anything about the self but has effectively set the stage for the discovery that is to come. A deeper inquiry also reveals the first apparent condition of the self, not yet made explicit: humans have the ability to form and dissolve beliefs and opinions entirely within their minds.

Descartes’s first target for demolition is the senses. “Whatever I have up till now accepted as most true I have acquired either from the senses or through the senses. But from time to time, I have found the senses deceive, and it is prudent never to trust completely those who have deceived us even once.”

We are often misled by “objects which are very small or in the distance.” This reasoning is easy to understand for anyone who has momentarily mistaken an inanimate object, such as a rope in a dark room, for a living thing like a snake. Descartes contends that stronger sense-derived beliefs, like the fact that I am currently sitting in front of a laptop screen, are not beyond all doubt either. I could be dreaming that I am currently sitting in front of a laptop screen, lacking “any sure signs by means of which being awake can be distinguished from being asleep.”

One could argue that even though our senses sometimes deceive us, they usually work well. Similarly, while we may not always realize we are dreaming when we are dreaming, we can sometimes wake ourselves up. However, this only reaffirms Descartes's method: anything even slightly doubtful is considered false.

Reaching the foundation - what is beyond all doubt?

At this point, he is still left with something seemingly certain and indisputable: arithmetic and geometry. “For whether I am awake or asleep, two and three added together are five, and a square has no more than four sides. It seems impossible that such transparent truths sound incur any suspicion of being false.”

After contemplating if God could make him go wrong every time he adds two and three or counts the sides of a square, he considers an even more radical idea:

I will suppose therefore that not God, who is supremely good and the source of truth, but rather some malicious demon of the utmost power and cunning has employed his energies in order to deceive me. I shall think that the sky, the air, the earth, colours, shapes, sounds and all external things are merely the delusions of dreams which her has devised to ensnare my judgement.

Descartes uses the concept of a malicious demon with complete control over his beliefs to reach the depths of doubt. He reaches a point where he is open to the possibility that he may have to "recognize for certain that there is no certainty."

In his Second Meditation, in the midst of complete uncertainty, Descartes finds the foundation of his philosophical approach: the recognition of his own existence (or more accurately, the denial of his non-existence.) There is one thing he cannot doubt:

…if I convinced myself of something then I certainly existed. But there is a deceiver of supreme power and cunning who is deliberately and constantly deceiving me. In that case I too undoubtedly exist […] I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.

The insight that even a deceiver must necessarily be deceiving someone or something is Descartes’s undeniable truth that even the most deceptive forces cannot invalidate. The very act of doubting his existence serves as proof of it.

Understanding the essence of self - what is the “I”?

In the process of uncovering this truth, Descartes highlights a fundamental aspect of the self: its self-evident existence. When all other beliefs are demolished, the existence of the self is the only thing one can be absolutely certain of.

He then seeks to understand the true nature of this "I" that necessarily exists. He reflects on "the whole mechanical structure" and different body parts, his basic drives for growth and nourishment, his ability to move, and his capacity for sense-perception. However, when assessed alongside his prior doubts about possessing these attributes, it becomes clear that none of them are essential to a self that undoubtedly exists.

What remains becomes evident:

At last I have discovered it — thought; this along is inseparable from me. I am, I exist — that is certain. But for how long? For as long as I exist […] I am, then, in the strict sense only a thing that thinks, that is, I am a mind, or intelligence, or intellect, or reason.

The self is “a thinking thing.” Rather than understanding the self as merely a physical thing, Descartes sees it as primarily defined by the act of thinking.

He deepens his exploration of thought, and by extension the self, by using the example of a piece of wax. “I put the wax by the fire, and look: the residual taste is eliminated, the smell goes away, the colour changes, the shape is lost, the size increases; it becomes liquid and hot, you can hardly touch it, and if you strike it, it no longer makes a sound. But does the same wax remain? It must be admitted that it does.” The senses, once again, cannot help him understand the essence of the wax. Even the faculty of imagination is “unable to run through [the] immeasurable number of changes” that the piece of wax can undergo:

…the nature of this piece of wax is in no way revealed by my imagination, but is perceived by the mind alone […] the perception I have of it is a case not of vision or touch or imagination — nor has it ever been, despite previous appearances — but of purely mental scrutiny.

The wax analogy leads Descartes to claim that the mind’s grasp of the self and objects is superior to that of the senses and the faculty of imagination:

I now know that even bodies are not strictly perceived by the senses or the faculty of imagination but by the intellect alone, and that this perception derives not from their being touched or seen but from their being understood; and in view of this I know plainly that I can achieve an easier and more evident perception of my own mind than of anything else.

At its core, Descartes's conception of the self is that of a self-evident thinking entity with pure mental faculties that don't rely on physical interaction.


Ultimately, Descartes arrives at controversial yet important ideas about the nature of the self. What begins as radical skepticism of everything leads to a clear insight: “I am, I exist.” This moment of clarity establishes the self’s existence as intimately connected to its capacity to think.

By embracing and demonstrating the method of doubt, Descartes offers a model of inquiry that remains deeply relevant today. It challenges us to question the foundations of our beliefs and to seek certainty in an uncertain world.

Reflecting on these insights and inspired by the challenge to continue the process of scrutiny, I am left with more lingering questions about identity, self, and Descartes's method of doubt:

  • Is discarding anything with the slightest possibility of doubt a reasonable approach?
  • Does the act of thinking necessarily require a thinker?
  • Is the melted wax really the same as the original piece of wax?
  • Can the mind exist entirely distinctly from the body, as Descartes implies?