Can We Know the External World Through Our Limited Sensory Perceptions?
(1) Our senses are limited.
(2) We can only perceive the world through our senses.
(3) Therefore, our understanding of the external world is limited and not sufficiently justified in assuming that it is absolute in its existence.
"What will then be true? Perhaps just the single fact that nothing is certain," so were the words of one of the most infamous Western philosophers, Rene Descartes (Descartes, 1998, p 63). Descartes is infamous for the proposition that we cannot believe much of what we previously had, based on the concept that all can be doubted with its connection to our sensory perceptions. Essentially, we only have a limited knowledge of the external world based on our own limited perceptions; yet this limited knowledge is in no way sufficiently justifiable to say that we can truly understand the existence of the external world as it occurs beyond the realm of our sensory experiences. Therefore, our understanding of the external world is limited and not sufficiently justified in assuming that it is absolute in its existence.
Descartes began to question the existence of the external world through doubting the things he thought he knew because of his sensory experiences. Understanding that when things are possibly doubted, their truths are not absolute is a primary foundation for understanding we have no real way to know in absolute certainty that the external world actually exists. Descartes' method of doubt requests his audience, as well as himself, to begin to doubt everything because what we know has come from questionable sources.
"I will stay on this course until I know something certain, or, if nothing else, until I at least know for certain that nothing is certain," (Descartes, 1998, p 63). He is essentially asking us to doubt everything that cannot be proven as an absolute truth. This is a step towards rethinking the external world itself as being doubtful in its existence. Here, the research suggests that "Descartes indicates how we are able to guarantee our beliefs about reality by limiting what we believe to what is indubitable or is based on what is indubitable" (Daniels, 2012). Due to the fact that our knowledge of the external world is open to possible doubt, Descartes is throwing out the idea that it even exists. Descartes writes, "eventually I am forced to admit that there is nothing among the things that I once believed to be true which is not permissible to doubt -- and not out of frivolity or lack of forethought, but for valid and considered reasons" (Descartes, 1998, p 62). His first Meditation is a compelling testament of his experience. Descartes realizes that most everything he thought was true was not, because he could not prove it beyond the presence of containing doubt. Here, BonJour writes that "anything for which such a basis for doubt can be found is something that might conceivably be false and so is something that cannot be accepted or relied on if the goal is to conclusively eliminate all error" (BonJour, 2002, p 12). Descartes uses this method of doubt to question the existence of the external world (Daniels, 2012). If we have the possibility for doubt, the external world cannot exist in absolute truth to us.
The biggest cause of doubt to both Descartes and subsequent philosophers after him is the limitation of our own perception. Descartes saw that our perception abilities were limited, and thus did not always give us the power of absolute certainty when perceiving the external world around us. Yet, our only knowledge of the existence of the external world comes directly from our senses. It is describes as this" "it is subjective sensations or subjectively experienced qualities that are experienced most immediately; and it is upon the experience of these subjective entities or processes or whatever exactly they are that the justification, if any, for the resulting claims abut both the material world and my experiencing of it depends" (BonJour, 2002, p 107). Our senses are limited, and thus only provide limited information about the real external world that we cannot verify as being absolutely true. Thus, e cannot prove with absolute conviction that the external world around us even exists beyond a reasonable doubt, because all of our evidence is tainted by the limitations of our perceptions. Our senses are limited, and thus can deceive us because of the fact that they are not fully or justifiably trusted. They become the possible evil genius, which could trick us into believing something that is not true. The very fact that our senses can be misleading or false in any context, then places them in doubt altogether as a primary source for gathering evidence to support the absolute existence of the external world that exists beyond the contexts of our own logical minds.
Based on the limitations of our senses, there is no way of telling with absolute certainty that the external world exists, because all of our evidence is biased by those limitations. We cannot know the real world because we cannot absolutely prove its existence beyond doubt based on the limitations of our own senses. Human beings are thus unable to know the true nature of the real world around us because we are limited by the bias of our perception. Here, BonJour writes, "we have so far tentatively accepted the conclusion that the immediate object of awareness in perceptual experience is never an external material object, but it is instead something of a quite different sort" and is actually only from the limits of our own perception (BonJour, 2002, p 129). Our senses do not provide enough reason for sufficient justification to say we truly know the real world as it exists outside of our own limited perspective. They are not justified because of their innate limitations. They have a possibility of being misleading or false, and therefore do not have enough justification to believe the truth of the external world. Thus, "whether such beliefs about success are actually justified by the experience in question is just one facet of the problem of the external world" (BonJour, 2002, p 272). This is essentially a type of representationalism, where information about the external world can be represented by our sensory proximity to various stimuli. However, the only thing we really know for certain is our own logic and reasoning, not the limited information provided to us by our senses. We can only state with absolute certainty in the existence of ourselves, our own minds, because that is the only thing we can be justifiably certain of. The rest of the external world is questionable because of the limitations of our own perceptions. Thus, Descartes threw out all of his belief in the external world because of its uncertainty being based on such limited information provide to us by our senses. The only thing we can really believe exists is ourselves, our thinking and rational minds. This is the foundation for Descartes famous saying, "cogito ergo sum," or "I think therefore I am." It is a statement that we cannot believe in the absolute existence of the external world, only ourselves. All Descartes can know with absolute certainty is that he is "a thinking thing" (Descartes, 1998, p 65). With this concept, the possibility of knowing the truth in the external world and its existence is shattered.
There are a number of counterarguments. Many people for generations after Descartes initial philosophy have tried to show a greater ability to rely on our senses as a mode of collecting evidence on the existence of the external world. BonJour once argued against Descartes completely himself. However, even BonJour began to change his assumptions regarding the nature of foundationalism and the classical traditions of philosophy stating that our senses are truly limited. One of the most famous voices for a counter argument is John Locke. He presents a differing version of representationalism, where Lock believes that there is enough justification to trust in what our senses represent to us from the outside external world. According to the research, "Locke's view, according to which our subjective sensory experience and the beliefs that we adopt on the basis of it constitute a representation of the external material world, one that is caused by that world and that we are justified in thinking to be at least approximately accurate" (BonJour, 2002, p 135). John Locke presents a major counter argument in the idea that our senses do actually provide sufficient justification to say we can truly understand the external world. Our senses provide enough justification to understand material objects outside of the realm of our own minds. As such, "Locke's view is clearly that our beliefs or opinions about material objects existing outside of our minds are justified by our ideas of sense" (BonJour, 2002, p 130). In this, Locke is trying to place more reliability and truth on our senses…