Descartes undertakes an arduous task in his attempt to, “…establish anything firm and lasting in the sciences (The Meditations…).” In order to construct a foundation of the sciences, The Meditations on First Philosophy displays Descartes skepticism challenging all beliefs made to be knowledge. Two arguments propose the possibility that “all …(Descartes’) opinions are false,” and must be doubted in order to find absolute truths.
So that one may come to see that it is possible to deceive oneself in empirical knowledge, or that gained from the senses, Descartes offers the “dream argument.” Secondly, even though there are certainties known regardless of unreliable senses, it is possible there is a force that deceives us further still. This second argument, enhancing the skepticism throughout, is the “evil demon argument.”
Both these arguments make up what is titled, Meditation One, of the …First Philosophy writings. Descartes’ reasoning convinces to the point of the oblivion of what can be known as certainty.
The beliefs in question for Descartes are those that the majority of minds cling to for scientific reassurance. This comfort is undermined by his arguments’ “attack…” on the “…principles” of our claims to knowledge. Simply put, he poses the question of how can one be sure that what is believed to be known is true and certain? If one is to trust that the senses reveal how the world is and not how one believes it to be, it must come in the form of knowledge that is certain.
Most knowledge is derived from the senses and as realized in the “dream argument” may sometimes deceive us, thus making them unreliable. The “evil demon argument” becomes necessary when one comes to realize that these same senses convey matters that “one simply cannot doubt.” To be able to doubt the senses is no small feat, as without them it would seem that we experience nothing and are useless. Once this doubt is in place, one can be equally skeptical of the knowledge derived thereof.
The “dream argument” sets forth the idea that one cannot be certain of the senses when awake, because the mind is also capable of conjuring images when dreaming. These images exist as a product of the mind and are, as Descartes describes, like painted images. If it is so that the mind creates these images in our dreams, could it be that the mind also creates images when awake. In other words, if one cannot rely on what is seen to be certain when dreaming, how can one rely on what is seen when awake.
This element of illusion is manifest in a disease like schizophrenia where the mind hallucinates images. Someone who is schizophrenic cannot rely on or be certain of what they see, and the argument holds that this uncertainty can exist in a healthy mind as well. The senses being deemed unreliable and having such an important role in acquiring knowledge cover much ground for Descartes to undermine his belief system. Still there is much to be certain of and it can be argued that there is knowledge that exists outside the senses. Not knowledge in the terms of experience gained or observation, but something seemingly concrete like mathematics. Although this is a discipline learned through the senses, it is something “indifferent as to whether these things do or do not in fact exist.” How can one begin to falsify the roots of arithmetic or geometry? The only answer is found in the question of what are the intentions of a being or force responsible for our creation and all that exists?
For Descartes, this creator for the sake of argument is not the supremely good and all knowing God we are accustomed to. Instead it is an “evil genius” capable of deceiving us and thus enters his “evil demon argument,” which is used to explore this suspicion of falsehood in fundamentals.
The “evil demon” argument allows Descartes to uphold the ability to doubt all that seems certain. Such as the fact that one plus one is always two, except in the possibility that a supreme being has in fact deceived one in the calculation. Not wanting to rely on habitual opinions that are credulous, Descartes avoids this by supposing to be tricked by a God who may want to deceive him from a truth.
The presence of an evil being bent on deceiving us offers doubt to most anything, whether science, mathematics or perception. Though this argument seems to be contingent to the “dream argument,” it is essential if we are to dispose all notions of certainty.
If Descartes cannot undermine all disciplines of the sciences and mathematics, then he cannot thoroughly undermine the foundations he wishes to doubt. He uses the “evil demon argument” to cast uncertainty on what seems indubitable. The “dream argument” supports that the sciences that are “dependant upon the consideration of composite things,” can be held in doubt (pg 15). A second argument is needed though for something as certain as mathematics. As he states, ” whether…awake or asleep, two plus three equal 5.” If this last statement is to be proven false it can only be so because of an unseen force that hides itself.
Though this testament to doubt is a historical piece whereupon modern science can now claim a more precise certainty. Although the basis of Descartes argument firmly embraces an everlasting notion that the skeptic will always have a home in the world no matter the proof made ready for use. He did a great service and his meditations are essential to all philosophy, allowing the thinker to reach outside of what we think we know.
All quotes from Descartes’ The Meditations on First Philosophy