What is Cartesian Skepticism, Cartesian Doubt, and Cartesian Dualism?

What is Cartesian Skepticism, Cartesian Doubt, and Cartesian Dualism?

June 27, 2021 Off By Felso

Your alarm goes off, you turn it off, get out of bed, get dressed, have your breakfast, and you’re ready for the day. But then something happens that you didn’t expect; you wake up, it was just a dream… In your dream you were getting up and getting ready for the day, but in reality you were sleeping soundly under the covers. If you’ve ever experienced something like this in your life, you should already know what I mean.

These dreams are known as “false wakefulness” and are quite realistic. Rene Descartes (1596-1650) also had such a dream in his time and started to think about it.

How could one be sure that he was not dreaming? Philosophy was just one of Descartes’ intellectual interests. He was a highly accomplished mathematician, and his real reputation comes from his discovery of the “cartesian coordinate system”.

Rumor has it that while he was following a fly hovering on the ceiling with his eyes, wondering how the fly would describe its position at different points led him to find the Cartesian coordinate system.

Science also fascinated him, he was both an astronomer and a biologist. His reputation as a philosopher rests mostly on his books “Discourse on Method and Meditations,” in which he examines the limits of knowledge.


Like many philosophers, Descartes didn’t believe anything without asking why he believed something, and he also enjoyed asking weird questions that other people wouldn’t have thought of. Of course, Descartes was also aware that life would not pass by questioning everything.

Undoubtedly, as Pyrrhon realized, it must have been quite difficult to live without trusting anything most of the time. For Descartes, however, it was worth the trouble to find something he was sure of, even once in his life, no matter what. For Descartes, the method that draws the way to reach real knowledge is known as “Cartesian skepticism”.

This method is quite simple. Do not accept as true anything that has the slightest possibility of being untrue. Think of a sack of apples. You know there are rotten apples in the sack, but you’re not sure which ones are rotten. What would you do to get a sack where you are sure there are no rotten apples left but only fresh apples?

You dump all the apples on the ground, check them one by one, and throw back into the sack only the ones you’re sure are healthy. While doing this, you can also throw away a few healthy apples that look a little rotten inside. But you still make sure you have good apples in your sack in the end. Descartes’ method of skepticism was more or less similar.

If you have a thought that says “I am awake while reading this”, you should definitely test it and accept it if you are absolutely sure that it is not false or misleading. If you have even the slightest doubt in your mind, you should deny it.

Descartes would review many of the things he believed in and question whether he was absolutely sure that they were what they seemed. Was the world really what it seemed to him? Could he be sure that he was dreaming?

What Descartes was trying to find was the only thing he could be absolutely sure of. Thus, he would be able to establish a solid ground for himself in the slippery reality. But there was also the danger of falling into a whirlpool of doubt and eventually thinking that nothing was right.

Descartes wanted to be skeptical, but his skepticism was different from the skepticism of Pyyrhon and his students. They thought that nothing could be known for certain; however, Descartes wanted to show that some beliefs are unaffected by even the most perfect form of skepticism.

Descartes first began his search for certainty with evidence obtained through the senses: sight, touch, taste, hearing and smell. Can we trust our senses?

Descartes concluded that we cannot fully trust. Our senses can sometimes deceive us. He could have made us wrong. Consider your eyesight. Can you always rely on your eyesight? Are your eyes always loyal to you? For example, a stick that you put in water appears bent when viewed from a certain angle.

A square tower may appear round when viewed from afar. Each of us has trouble with our eyesight from time to time. Descartes thinks it would be wrong to trust something that had previously deceived you. Therefore, it does not accept that our senses are completely reliable. He will never be sure whether his senses are deceiving him.

Maybe they don’t deceive us most of the time, but even the slightest chance that they could deceive means that Descartes could not fully trust them.

So where does that take him? The belief that “I am awake right now while reading this book” may sound very reliable to you. I hope you are awake and indeed reading. How can you doubt that? However, we mentioned that you can think that you are awake when you are dreaming. How can you be sure if you are dreaming right now?

You probably think your experiences are too realistic and detailed to be dreamy, but many people are