From the time we are born, we are constantly presented with new information. As that new information comes to us we discover new things, create new beliefs within our minds, and reach new levels of understanding. Unfortunately, not all the beliefs we hold are based on fact. Often we misunderstand the facts, or are confused by ideas we already hold. In our childhood, we often accepted as fact things which we now know to be false, based upon the testimony of people we had, at that time, considered to be expert. How many of those beliefs still remain undiscovered? What impact have they made on our lives?

Recognizing that the influence of false beliefs could impair scientific inquiry, leading to possible incorrect conclusions, René Descartes knew he must rid himself of those false beliefs before he could truly accomplish any valuable scientific discovery.

This is certainly a valid concern. Say, for example, Descartes wished to examine why the ocean appears blue. Ordinarily, he would consider what he knows about water and quickly realize that it is reflecting the color from the sky. But, what if Descartes had the false belief that the sky was not blue? Perhaps he is color-blind, and his examination is based on the testimony of other people. In this case, Descartes might never reach the correct answer. The reason for his confusion is false belief. It is because of this that Descartes begins his Meditations on First Philosophy .

But, for Descartes, the issue of concern was not mere falsehood. He intended not only to rid himself of those beliefs that were absolutely false, but also those that might be false. Any idea, which was not certain, would be discarded. Despite the greater degree of certainty he demanded, Descartes saw this as a lightening of his workload, since he would no longer need to prove the falsehood of his belief, but merely cast doubt upon it.

The process of eliminating false beliefs one at a time would be a practical impossibility. However, René knew that to destroy the foundations upon which those false beliefs rested would send them tumbling, akin to destroying the foundation of a building and watching the walls crumble.

Beginning, as he had planned, with the foundation of his beliefs, Descartes first considered where the majority of his beliefs find their source. He recognized at once that whatever opinions he held were caused by the deliverance of the senses. Yet, he also knew that he had in the past been deceived by his senses. For Descartes, this appeared cause for doubt. If his senses had led him to false belief in the past, how could he know that they would not do so again? Also, how could he know that they had not led him to other false beliefs, which had not yet been uncovered? Based on this doubt, Descartes denies all sense-based belief.

There are some problems with Descartes’ argument for rejecting the senses. One objection raised is that it appears paradoxical. If the senses have led us to false belief, how do we know this without consulting our senses? The proposition that we should deny our sense-based beliefs seems to be based on a deliverance of the senses.

If a person viewed a stick in water, they might take on the belief that the stick is bent; yet this is merely an optical illusion. If they withdrew the stick, they would see that it is straight and would recognize that their first belief was false. In this manner, a person can see that the senses might mislead a person. However, the second sensation (viewing the stick out of the water) was necessary to come to this belief. Were it not for a contradictory sense-based belief, the first opinion would be maintained, and we would never know that the senses can mislead us.

Descartes responded to this apparent paradox by attempting to show how the conclusion can be reached a priori . The manner he approached this argument was through the possibility of dreaming.

Descartes raised the point that at times when a person is dreaming, they cannot tell the difference between dream and reality. Within a dream things are possible which would not be in reality, so something that we perceive as being true within a dream might be false in reality. If we believed that we could fly, based upon a sense impression within a dream, we would hold a false belief. Because we cannot tell the difference between dream and reality, we cannot be sure that at any given time we are awake or asleep, and thus any sense-based belief is not certain.

There may be another problem with Descartes’ rejection of the senses. It could easily be said that the senses are not the cause of false belief; the cause is in actuality the mind itself. The senses do not create belief; belief is created by the mind to interpret phenomena.

Consider again the stick in water, what can we truly say about it, based upon that one image? There is a stick in water, where the stick meets the waterline it appears to bend sharply. If we remove the stick, what can be said about the second image? The stick no longer appears to bend. But are the two statements contradictory? Not without some unspoken premises.

The contradiction lies in prior belief such as continuity, or ideas about the composition of wood. If a person has only senses, they will accept both images as representations of the world and act accordingly. It is the mind which demands that a bent stick remain bent, the senses merely acknowledge the different appearances.

There is no answer to this problem in the First Meditation. Perhaps this was too Eastern a concept for the time period, and it never occurred to Descartes. More likely, the reason Descartes never addressed this issue had something to do with Descartes’ conclusion in the Second Meditation. Namely, the idea that thought proves one’s existence. For Descartes, to deny thought was to deny oneself. Perhaps he considered the argument using the terms "in the past, my mind has deceived me," and found it absurd that one could deceive themselves. For Descartes, "my mind" and "me" are equivalent. Unfortunately, these reasons seem more psychological than philosophical.

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