How do we prove something beyond reasonable doubt? We use empirical evidence, corroborate eyewitness accounts and analyze the information that we are given. Most of the tools that we utilize in order to prove that something is beyond reasonable doubt ultimately necessitate the use of our senses, i.e. sight, smell, taste, touch and hearing. This then produces the question, are our senses to be trusted? What can we be certain of without the senses? These questions form the basis of Rene Descartes’ Cogito Argument, which ultimately results in the famous saying, “I think, therefore, I am.”
Descartes’ goal was to build a strong foundation on which his philosophy was to stand. He believed that a strong philosophical foundation should ultimately be based on our most certain beliefs. His methodology for doing so was to place our beliefs under the scrutiny of radical doubt. Instead of trying to prove anything beyond reasonable doubt, Descartes rationalizes that every belief that can be doubted, even beyond conventional reason, should not form a part of his philosophical foundation.
Descartes’ radical doubt forced him to examine the fundamentals of what we think is certain. Most of our knowledge is attained through the senses. Descartes argues that anything we learn or infer from the senses can be doubted. This is because all sense perception can be deceived. When a person in extremely cold weather places their hands in room temperature water they might feel that the water is hot. When a person has an illness they might feel hot when it is cold or vise versa. To take this even farther, when a person is dreaming they do not think that they are dreaming. In their dream they believe that they see, smell, touch, taste and hear in the same way as they would while awake.
Descartes even goes as far as to say that everything he experiences could be the result of an evil demon deceiving him and the world itself being a fabrication created by the demon. He believes that the goodness of God would not lead Him to deceive his creation, however he writes that it is possible that, “some evil genius not less powerful than deceitful, has employed his whole energies in deceiving me; I shall consider that the heavens, the earth, colors, figures, sound, and all other external things are naught 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.”
If our senses cannot be trusted then it might be possible to find certainty in more abstract forms of knowledge, specifically mathematics. After all it would seem absurd to doubt 2+2=4. Except, that’s precisely what Descartes does. He argues that “how do I know that I am not deceived every time that I add two and three, or count the sides of a square, or judge of things yet simpler, if anything simpler can be imagined?”
Descartes, of course, does not really believe that the entire world might be an illusion and that he has erred every time he solves a mathematical equation. He forces himself to contemplate their possibility as to ascertain what is truly certain.
If everything, it seems, can be doubted then how can a person be certain of his or her own existence? How can we be certain of our existence when we cannot be certain that we have senses or even a body? Descartes argues that even if he was to be deceived into believing that he has senses and a body he must be something in order to be deceived. “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. So that after having reflected well and carefully examined all things, we must come to the definite conclusion that this proposition: I am, I exist, is necessarily true each time that I pronounce it, or that I mentally conceive it.”
What cannot be denied is that he doubts. If he doubts then it cannot be doubted that he thinks. If he thinks it undoubtedly necessitates that he is the thinker. If he is the thinker then without a doubt he exists. Therefore, I doubt, therefore, I think, therefore, I am.