PERCEPTION AS A TOOL FOR ACQUIRING KNOWLEDGE
For the rationalists, like René Descartes and Baruch Spinoza, the main source and final test of knowledge was deductive reasoning based on self-evident principles, or axioms. For the empiricists, beginning with the English philosophers Francis Bacon and John Locke, the main source and final test of knowledge was sense perception. In exploring perception as a tool for acquiring knowledge and the extent to which it is accurate we are actually in a way attempting to determine the validity and accuracy of empirical knowledge.
To understand whether perception can contribute to knowledge construction we first need to define perception and understand the elements involved in perception. One of the definitions that have been provided for perception is as follows: “Perception is the process by which organisms interpret and organize information received by the sense organs”. Through this we can interpret that the accuracy and reliability of conclusions drawn via perception depends on two factors- the accuracy of the sense data and the interpretation of this data by our mind.
The word that casts doubt on the conclusions that we arrive at via perception is ‘illusion’. Illusions are common in normal perception and are natural consequences of the way our sensory systems work. An illusion can be thought of as something that causes us to deviate from reality. Illusions can be classified into two main types- those with a physical cause and cognitive illusions due to misapplication of knowledge. Although the causes differ considerably these illusions still can produce the same distortions and this makes them difficult to classify.
The Muller-Lyer illusion, the Ponzo illusion, the Zollner illusion, the Ames room are just a few of the many examples that show how our senses can be deceived. The stick that appears bent underwater but is actually just a trick of light is probably one of the most widely used examples to illustrate and discuss illusions. If our senses can be deceived and our thought process influenced then how can we trust what we perceive?
Thus, illusions can be hard to justify and overcome and that makes trusting any knowledge gained through analysis of sensory data suspect.
Another problem which arises with perception is that perception is a causal process and causation takes time. Which means that at the time when perceptual processing is complete, the properties of perceived objects may be distinct from those possessed by the object when it was first seen by us. In extreme cases the object perceived may not even exist any longer. An example of the extreme case is the scenario when we perceive a star in the sky to exist when actually at that instant in time it may have ceased to exist or become a supernova. This is due to the enormous amount of time it takes light to travel the distance from the star to our eye.
However this aspect has a solution which is “One should reject the assumption that the object of perception has to exist at the moment we become perceptually aware of that object.” What we see is then to some extent the past.
These are the two main issues that challenge the empirical point of view in my opinion. Then what alternatives do we have to further our quest for knowledge. If we apply the principle of charity and completely reject the empiricist viewpoint what tools can we use to acquire knowledge?
Rationalists believe that all knowledge can be gained through reason and logic and that exact knowledge does exist and can be gained. Though there is a lot that we can learn purely through reason and logic, if we reject all empiricist data we will have no foundation to build on. If we cannot establish 'first principles' or certain unquestionable assumptions we cannot build any knowledge. We won't know where to begin and we wouldn’t be able to establish anything at all. This situation would be the same as one created by a skeptic, one where absolutely nothing is certain and one where the only thing you can 'Know' is that you don't 'Know' anything at all.
Thus, if we reject perception as a tool totally, we may never be able to gain any kind of knowledge through pure logical analysis. Immanuel Kant tried to solve this problem by fusing elements of empiricism with those of rationalsim. He distinguished three kinds of knowledge: analytical a priori, which is exact and certain but uninformative, because it makes clear only what is contained in definitions; synthetic a posteriori, which conveys information about the world learned from experience, but is subject to the errors of the senses; and synthetic a priori, which is discovered by pure intuition and is both exact and certain, for it expresses the necessary conditions that the mind imposes on all objects of experience. Mathematics and philosophy, according to Kant, provide this last.
Perception may not be a very accurate tool to gain knowledge but it is an important tool. Without perception we would never be able to gain any sort of knowledge of the external world. It is perception which provides the bridge between the physical world and our mental realm. In fact, scientific inquiry is heavily dependent on perception and sense data. This is because the principles of science always seek to explain observed phenomena.
We do realise the importance of perception in knowledge construction. That is why we seek to develop sensory systems in artificial intelligence. The very fact that we believe that sensory inputs and their analysis are vital for the development of artificial intelligence indiactaes that we do understand and appreciate the importance and contribution of perception to knowledge construction.
Conclusion: Perception lies at the root of all our empirical knowledge. We may have acquired much of what we know about the world through testimony, but originally such knowledge relies on the world having been perceived by others or ourselves using our five senses: sight, hearing, touch, taste, and smell. Perception, then, is of great epistemological importance.
