Descartes went as far as questioning whether one can trust one’s senses. He argued that because one’s senses can sometimes be deceived, how can one accept any information that has been received in a physical manner? It is evident that senses can, at times, be deceived. The Muller-Lyer, for example, tricks the viewer into thinking that two lines are of different lengths, when they are, in fact, of equal lengths. Descartes argued that since such blatant examples of sensual deception exist, how can one ever trust what one’s senses is perceiving? This was an effective argument because if information is perceived incorrectly then certainty cannot be achieved.
Dreams were Descartes’ second argument. He stated that because, at times, dreams can be so extremely intense and vivid, to the point where they mimic everyday lives one cannot determine whether they are part of one’s ordinary daily life. Since this is the case Descartes put forward an argument of continuity, whereby he stated that at times it can be near enough impossible to determine differences between your states of consciousness. Information gained through, therefore, one’s dreams can sometimes be confused with information that has been gathered during the day. This can lead to errors in knowledge.
Malcolm argued against Descartes’ dream argument by stating that in order to question the state of one’s consciousness one must be in a state of wakefulness. Many psychologists have refuted Malcolm’s statement for the simple fact that those who can experience lucid dreams would be able to question the state of their consciousness. Hitherto no one has been able give a good enough argument to successfully disprove Descartes’ argument.
The evil demon argument was Descartes’ most extreme argument. He posed the concept of a malicious deity. This malicious deity was proposed as being responsible for sensual deception. Since deception occurs it is logical to presume that ideas about the world can be questioned. Therefore, all things being equal, it is even possible to question one’s very existence (later Descartes argued against this with his ‘Cogito ergo sum’ statement). Descartes suggested that even a posteriori knowledge may be a result of implanted deceptions carefully manipulated and controlled by a evil deity. He suggested that this deity was evil because it is associated with lies, whereas a benevolent deity would not be.
Wittingstein tried to refute Descartes’ concept of doubt as a means to certainty. Wittingstein believed that language is a subjective rather than objective experience. He therefore argued that Descartes had incorrectly made use of the word doubt. Descartes used the word doubt to described that of which cannot be brought into light through adequate evidence. This term was used as an eliminator of questionable knowledge, therefore helping Descartes achieve true knowledge.
Wittingstein argued that Descartes had no grounds to doubt ‘questionable knowledge’ simply because he had nothing to check this knowledge against. For example, using Wittingstein’s concept, one can doubt whether it will be sunny tomorrow, but unless one experiences tomorrow’s weather, one has no grounds to doubt otherwise. The weather could be sunny, but it could also be stormy only experience is ultimate evidence. Wittingstein therefore stated that Descartes’ lack of relativism meant his doubting was made on no grounds. Descartes could counter this argument by using his Archimedean point, whereby it is not always necessary to prove that something is right to accept that it is, because some facts will remain true no matter what. Descartes had effectively made a post hoc ergo procter hoc statement whereby he assumed that because leverage principles are based on true knowledge it must therefore be true that Archimedes’ ‘the world can be lifted’ statement was feasible.
Conceptual relativism suggests that when one states, for example, ‘doubt’, others may not comprehend the word in the manner it was originally intended. What is considered relatively meaningful to one person may not be to another. Wittingstein suggested that language is a system in which the structural aspect of its use is determined and governed by social rules. It may be that, since Descartes was of a different society to that of Wittingstein, Descartes’ use of the word doubt was adequate and its intended meaning permissible to his society. Unless Wittingstein knew for sure that both mentioned cultures were identical the grounds for his argument is substandard.
A good analogy to support Descartes’ doubt argument is that of swans. One can count 1000 white swans and come to a conclusion that all swans are white. This is often what some sciences do, they observe patterns and, together with assumptions, aims to come up with a conclusion, which associates the assumption with the evidence. Descartes argued that knowledge based solely on sampling techniques is unjust. If one concludes that all swans are white based on the observation of a sample then one would most certainly be wrong, because there are indeed black swans present in New Zealand.
Descartes aimed to acquire knowledge that was not polluted with probability or observation of patterns from a sample. Descartes believed that knowledge such as maths, physics and astronomy were sources of true knowledge this is because they are associated with concepts that are not under influence from other factors. For example 2 + 2 must be 4, the ‘mustness’ is logical and independent of all other factors. The realm of numbers cannot be easily affected by any other factors, for Descartes’, subjects that are influenced by this realm seem to be the best sources of true knowledge.
At the end of Meditations 1 Descartes is still seeking for certainty. Hitherto it is yet unclear whether such level of comprehension can be achieved. Descartes does successfully make one question every aspect of one’s beliefs. It may be that one lives out one’s life according to facts that are untrue. Whether Descartes was right or wrong is beside the point, it does not affect the way one carries out one’s existence. If a whole species, for example, accepts a fact as being true surely it must have some truth because of that species’ perception of the fact. One can compare it to the blind leading the blind. The majority usually prevails, if no one knows otherwise the fact will remain true.