Do you exist?

Do you exist? If you are a sane individual (i.e. not a student of philosophy), you might be tempted to slap me in the face. Please don't, yet: as I will now proceed to make you doubt your own existence. If you are of the faint-hearted lot, please do not read what follows.

It starts with Descartes

You might be wondering, "What is a mathematician doing here? Isn't Descartes the guy who postulated the Cartesian coordinate system? What is he doing here?" You are right! This is the guy whom the Cartesian coordinate system is named after (as he postulated the idea). He is also considered to be the father of analytic geometry.

However, many people might not know this: he is often considered to be the father of modern philosophy as well. This guy was born in a wealthy and privileged family, but became a gentleman soldier to support the Protestant Prince Maurice against the Catholic parts of the Netherlands (which parts later formed Belgium). He also had a child with his housekeeper. Okay, this is getting personal: let's move on.

Okay, back to Descartes being a philosopher. In 1641, Descartes published "Meditations On First Philosophy". The first two meditations of this book are considered to be epoch-making, and a crucial first step for any modern philosophical endeavor. In them, we shall find this blog's central question.

The evil demon

Let me start this section by quoting, from the book, the great man himself, "I shall then suppose, not that God who is supremely good and the fountain of truth, but some evil genius not less powerful than deceitful, has employed his whole energies in deceiving me;" (emphasis mine)

 

Let me ask you an absurd question. How are you certain that what you perceive is real? Isn't it possible that you are being deceived? Isn't it possible that what you are perceiving is just an illusion? Isn't it possible that an evil demon has employed all of his energies in deceiving you? This is the exact question Descartes attempted to wrestle with.

He assumed that an evil demon, or a malin génie, was constantly deceiving him. In his words, "I shall consider that the heavens, the earth, colors, figures, sound, and all other external things are nought but the illusions and dreams of which this genius has availed himself in order to lay traps for my credulity; I shall consider myself as having no hands, no eyes, no flesh, no blood, nor any senses, yet falsely believing myself to possess all these things;" In brief, he began to doubt the existence of everything, including the existence of his own self!

What followed was pure agony for Descartes, "The Meditation of yesterday filled my mind with so many doubts that it is no longer in my power to forget them. And yet I do not see in what manner I can resolve them; and, just as if I had all of a sudden fallen into very deep water, I am so disconcerted that I can neither make certain of setting my feet on the bottom, nor can I swim and so support myself on the surface."

A way out

Now, how did Descartes get himself out of this mess? Watch the next episode to find out! Haha. Okay, let's get serious. Descartes started by putting aside all that in which there is the least doubt. He wished to continue down this road until he found something which is certain, or at least, until he had learned for certain that there is nothing in the world that is certain.

Then, he found something. Something certain. He observed, "But I was persuaded that there was nothing in all the world, that there was no heaven, no earth, that there were no minds, nor any bodies: was I not then likewise persuaded that I did not exist? Not at all; of a surety I myself did exist since I persuaded myself of something [or merely because I thought of something]. But there is some deceiver or other, very powerful and very cunning, who ever employs his ingenuity in deceiving me. Then without doubt I exist also if he deceives me, and let him deceive me as much as he will, he can never cause me to be nothing so long as I think that I am something." (emphasis mine) 

Do you get it? An evil demon cannot possibly deceive me to think that I exist when in reality I don't because for the demon to deceive an entity, that entity must exist. Otherwise, who is the demon deceiving? So, I can know for certain that I exist. Put simply, if my mind is being deceived, then my mind must exist for the evil demon to deceive. 

This can be thought of another way. I can be certain at least that I am doubting. Doubting is thinking, so I can be certain that I exist; otherwise, who is doing the doubting/thinking?  This spurred his famous saying, " I think, therefore I am." We have reached Solipsism: the belief that only one's own mind exists for certain. 

Conclusion

The line of skepticism introduced by Descartes became known as Cartesian skepticism. Although philosophers found holes in his ideas later on, the ideas he promulgated changed philosophy forever, and yeah, you don't have to worry. You exist. Or do you?