Sense perception is one of the four ways of knowing. It is our senses that give us the ability to smell, hear, touch, see and taste. As we use these abilities to perceive the world around us, how much can we rely on them to give us the truth? This also begs the question, when should we trust our senses to give us truth? Epistemology is one of the main branches of philosophy1 which attempts to answer these questions. We identify an epistemological problem; our knowledge of the external world that may be misguided by our senses. When we speak of ‘trusting’ our senses, it is referred to whether we may ‘rely’ on our senses, and use our senses as valid measures of our existing world. Our senses are used so often since they are the most immediate forms of the ways of knowing. But our senses can be fallible. To explore these issues, we will look into the arts and the natural sciences.
G. E. Moore (1941) asserts that “a thing can’t be certain unless it is known”. He believes that this differentiates the word ‘certain’ from the word ‘true’. Something can be true that is not known by anybody, but it can’t be certain2. Thus truth lies in reality, independent of whether it is known or not or how it is perceived. Truth is defined by several substantive theories, which all commonly agree on knowledge that represents reality. Able to distinguish truth helps to answer; how much can we trust our senses in giving us truth? Each individual perceives reality through their senses, and then interprets this perception by associating it with their existing knowledge. If a person’s senses gave an identical representation of reality, this does not mean that their interpretation of reality is true.
The different modes of sense perception are inseparable from the other ways of knowing: reason, emotion and language. This is because as our senses attempt to mirror reality, they require other ways of knowing to determine what we select to hear, see…etc. In my first theory of knowledge lesson, the class was asked, “what can you see?”. A student eventually replied, “what do you want us to look at Sir…?”. The purpose of the teacher’s request is to exemplify the selective nature of our sense perception and in this case, it required reasoning. As we have established that truth lies in reality, the selective process of our senses without the involvement of the other ways of knowing can distort our understanding of truth.
By experience, most people can notice that vision can play tricks on them. Submerging a straight stick into water will give the optical illusion that the stick becomes bent. Similarly, rail road tracks in the distance are seen to converge. We know that both of these are untrue, but our perception gives us this impression of reality. Thus our sense of sight is misleading in some way. One can argue that the stick is truly straight because once it is out of the water, it can be seen as straight.
But how does one know whether it bends under the condition of being submerged in water? From this confusion, one becomes doubtful on the reliability of their sense of sight, and may use a different mode of perception. For example, one may feel the stick to be straight underwater by touching it. But this gives rise to the issue as to what justifies a mode of perception to give us truth more accurately than another.
However, the sense of touch may be just as fallible as sight. For example, assume that a person’s left hand is very cold, and the right hand is extremely warm. If this individual puts both of his hands into the same bucket of water with the same temperature throughout the water, the cold hand will feel warm and the warm hand will feel cold. This creates conflict between the senses of touch. Thus, this other mode of perception cannot be trusted either. Since we are in doubt of our senses of both sight and touch for the previous example, we must use other ways of knowing. We may use reason to justify that the stick is straight both in and out of water. Descartes’ law, the law of refraction, must be used to draw a conclusion and support the sense of touch that the stick never bends. Thus when we are in doubt about the accuracy of our senses, it is difficult to trust them to give us truth.