The question of whether we should trust our sense comes to us from the ancient times. Since the beginning of philosophy and thought, humans wondered whether the world is the way they see and experience it. With the advancements in philosophy, such doubts even framed out in a separate field of thought. Many thinkers were very skeptical about the contrast between the world as we perceive it and the way it really is and what role do our senses play in the process of perception and understanding. Descartes and Hume are two of the most prominent philosophers whose views regarding this issue show that we cannot totally trust our senses in judging about the external world. In this work, I will argue that the senses can give us the truth about the external world, but only when coupled with imagination and reason, considering that the latter are more important to perception than the former. My arguments will be based on the positions held by Hume and Descartes.
In the discussion concerning the role of the senses in our perception of the real world, it is important to start from finding whether there exists something as "real world" and whether it can be perceived. Rene Descartes and David Hume approach this issue differently. Descartes employs radical skepticism and total denial of the reality of the world while Hume uses much more moderate approach.
Rene Descartes in his Mediations on First Philosophy puts forth an argument that all external world may be an illusion, and therefore the senses may be rendered useless at all. He starts from the point that his senses often deceived him and what he considered right turned out wrong later. He discusses that senses can be deceptive and gives an example about dreams. When we are dreaming, Descartes asserts, we experience the world of dreams as real – we may be feeling like standing on a sunlit lawn while actually lying in bed at night (Descartes and Haldane 1-7). But he does not stop on this and pushes this argument further coming to its most famous form - “evil demon” argument – the most radical form of skepticism. Descartes asks that if a powerful demon deceives his senses about everything he ever knew, about all his experience, about the external world and even about his body what is he left with (Descartes and Haldane 1-8)? What can be known for certain? Descartes comes up with the answer that if he is deceived then, he at least exists ("Cogito ergo sum") (Descartes and Haldane 1-9). From this position, he proceeds to prove that God exists. Descartes suggests that he has the idea of a perfect being and what has perfect effect must have the perfect cause. He cannot be this perfect cause of the idea of God, which means that the God indeed exists (Skirry). And the last step Descartes makes returns him back to the real world. He states that he was created by God and given the ideas about the external world and that it exists. Since God is not deceiver this must be true from whence he concludes that external world really exists (Descartes and Haldane 1-26-1-28). Having found that there is actually what to perceive, Descartes follows further to determine the role of the senses in this process.
Having determined in his inquiries that the senses cannot be the sole basis of perceiving reality, Descartes finds that perception is impossible without applying reason. Senses, as he has formerly found, are deceptive and do not serve as the only means of knowing about the external things. Descartes makes an assumption that the process of understanding of any physical object is grounded on grasping the idea of the object. In proving his assumption, he proceeds from the opposite and makes an example about the piece of wax (Descartes and Haldane 1-11). If we observe a piece of wax, he says, we may note its physical characteristics – its distinct shape, color, odor, taste, and temperature. We know that it is wax before our eyes. If the wax is heated it starts to melt and eventually loses all of those features it formerly had – it has another color, shape, temperature, and even smell. But we still consider that it is wax. If wax cannot be judged by its physical appearance, then maybe it is the other non-sensory characteristics that we rely on. For wax, they would be extended, transformable, etc. But those features cannot be sense directly; maybe they are processed by imagination? But we cannot imagine all of the possible configurations that the mentioned characteristics impose with regard to wax. We do not image all possible forms it may take and all the sizes and positions it may take. Thus, it is not the imagination which is responsible for the understanding. Hence, it is only mind which is left. From this, it can be inferred, that we do not rely on our physical senses in perception but on our reason. It should be noted, however, that Descartes does not deny the importance of senses in the act of perception because it cannot be the activity of sole mind because it needs some reference point from which to proceed. He suggests that our understanding of the external world is based more on reason than on the senses.
When approaching the issue of sensual perception, David Hume makes his starting move in regard to the problem of reality from the point of expediency. In contrast to Descartes skeptic position, he states that, in order for us to make any inquiry at all, we need to assume that the external world exists and that it is “real” and thus can be perceived (Fieser).
David Hume starts his inquiry from finding on what basis do we conclude about the continued existence of the physical objects in the external world. The continued are the objects which actually exist and are independent of conscience, in contrast to them, interrupted are the objects existence of which is dependent on conscience. Hume suggests that senses cannot be this basis. If we would rely solely on our senses, then we would conclude that objects tend to appear and disappear as we point our attention to or from them. This is obviously not the case because we consider external objects to be existent regardless of our perception. So, it is not the senses that are responsible for our understanding of the external objects but something else. This could be the reason. But the reason is not required for making the decision concerning the continued existence of the external objects because we do not need to think thoroughly about it or apply philosophical principles to make such judgment. In support of this, Hume tells that many people do not use reason at all, and still they agree upon that the external objects exist regardless of us. So, accordingly, if only reason, senses, and imagination can be responsible for our perception then it must be imagination that guides our ideas of continued existence of the external objects. Hume suggests that we attribute the continuity of existence to the objects based on the activity of our imagination which compares impressions which we experience now, experienced in the past, and anticipate. He finds that there are two distinct characteristics based on which we decide that the object has continued existence. They are coherence and constancy. Suppose we are looking at the tree, if we turn out from the tree and lose it from sight and then turn back, we will see the tree in the same place. This is the expression of constancy in senses which makes us think than tree exists disregarding our perception, However, if the tree is cut down while we are not looking at it, we will still assume that we see a tree, although it will look differently and be in another position. Coherence is the reason for that. It consists in the dependence of changes in external objects we perceive on each other. So, when we observe the tree being not the same as when we observed it before we still consider it as existing independently of us because these two impressions are connected to each other and the change occurred conforms to our assumed possibilities of it. This, however, poses another question: do our perceptions have continued or interrupted existence? The philosopher gives his answer to this inquiry and draws a sharp distinction between these two categories.
David Hume asserts that there is a significant difference between perceptions and objects. He begins by stating that all external objects possess two distinct types of characteristics. The first type encompasses volume, mass, shape, solidity, and motion. These impressions have continued existence. The second group is the taste, color, smell, sound, and heat – these do not have continued existence because they cannot be deprived of feelings and experience. Following this classification, Hume asserts that while it might be tempting to assign continuity to our perceptions on the basis of the argument presented in the previous part but it would be a mistake. The perceptions and objects are two distinct kinds of bodies which can be readily proved by the following argument. If we push on one eye with a finger, we will see the external world totally different from how we see it with the other eye. Thus, the perceptions are dependent on our organs and possess interrupted existence. The existence of a single object cannot be at the same time interrupted and continued this is why external objects and our perceptions are two distinct bodies. Accordingly, the view that Hume stands unites the imagination which assumes the continued existence of the objects and reason which imposes the interrupted existence of our reflections.
The views of Hume and Descartes regarding the role of senses in perceiving the real world are very much alike but still possess difference. Both philosophers assume that senses might be deceptive and that they are not the only source of our understanding of the external world. While Descartes attributes mind with the power greater than senses in shaping our perception by processing and identifying ideas, Hume stands that our understanding of the external world is dualistic: it consists of reflections in our mind and imagination of the objects. The former does not deny the possibility that our perceptions are the exact reflections of the external world. Moreover, he asserts that our understanding and knowledge of the objects not only originates from our mind but that effective information can be known about the external objects by solely operating our own mind. From Hume's inquiry, it can be inferred the contrary – that our perception is different from the objects. All we can do with our reason is to manipulate perceptions and ideas, but we will never be able to step outside our impressions. Hume and Descartes are both skeptical about the supremacy of physical senses in the process of perception, but they attack senses from different perspectives. Hume does it from the inability to give the direct view of the real objects, and Descartes from their deceptiveness and inferiority to reason.
It may be objected, however, that even incorporating imagination into understanding cannot give us the truth about external world because we would still be operating perceptions with our mind which are different from the actual objects. We can respond to this objection that it is true that perceptions and objects are different bodies, but that does not imply that perceptions do not represent the truth about the world or are deceptive. The process of perception consists in interpreting sensory input based on our previous experience and memory. By applying reason it can be found whether this information is truthful and by comparing it with what imagination offers us we can know the extent to which our perception agrees with the external world. By using these faculties, we can doubtlessly find the truth about any of the characteristics of the external objects defined by Hume. We can compare the perceived attributes of the object (the ones of continued existence) to the previously set standards by using our mind and obtain truthful information about the external world. The secondary characteristics (taste, smell, etc.) are perceived directly since they do not exist independently of our conscience.
As it has been proved by using the arguments of Descartes, Hume, and their combination, the sole senses cannot be used to know the truth about the external objects. But when reason and imagination are applied to the process of understanding truth about the world can be devised. This inference implies that the world we live in can be understood and come to know to a reasonably truthful extent. However, this is only possible by reflecting and pondering on our direct sensual perceptions of it and comparing it to the images provided by imagination.
References
Descartes, René and Elizabeth Sanderson Haldane. Meditations On First Philosophy. Print.
Fieser, James. "Hume, David | Internet Encyclopedia Of Philosophy". Iep.utm.edu. N.p., 2016. Web. 28 Apr. 2016.
Skirry, Justin. "Descartes, Rene". Iep.utm.edu. N.p., 2016. Web. 28 Apr. 2016.
.
