The human sensory faculties, in addition to the processing power of the brain, play a vital and definitive role in how knowledge is acquired. The five major sensory faculties are sight, smell, hearing, taste and touch. Cognition is the higher faculty that integrates and interprets inputs from these five senses. But what is also interesting is that the brain, rather than being a passive recipient of inputs also directs and conditions the other sense organs. This makes the brain the most powerful sense organ, for it can potentially control the flow and the meaning of information that is gathered through the five basis sensory inputs.
There are several factors that determine the accuracy of sensory information. The quality of the information source is one and the health of the receiving sensory organ is another. The conduciveness of the medium of transmission is also a key factor. The way these three factors interact and compound is best illustrated through the example of listening to the radio. Thrown in this mix is the nature/nurture divide that adds complexity the problem of information acquisition. Nature plays a role in that the innate intelligence and modes of survival of the species (ex. carnivorous or herbivorous) determine the necessity for perceiving relative threats, opportunities, etc. In other words, the way animals are programmed to fight or flee and what to eat and what to shun determine their capacity for perceiving select information out of all the available data. Other factors such as health condition, age, etc all have a bearing on the efficiency and accuracy with which information is gathered through the senses. (Pomerantz, 2003)
Philosophers since ancient times have grappled with the nature, scope and veracity of human knowledge. In fact, the philosophical discipline of epistemology concerns itself wholly to answering such questions. Epistemologists generally agree that human knowledge is largely a product of human sensory capabilities. In other words, our capacity for knowledge is limited by the range and depth of our sense faculties in receiving and interpreting data. Thus, understanding the roles of nature and nurture are essential to the epistemological analysis. To the extent that human beings are a product of a long line of evolutionary adaptation, our DNA and the basic imperatives for the survival of our genes (the building blocks of DNA) dictate and define meaning. Hence, from the point of view of our species, knowledge has an evolutionary role, namely that of survival. Perhaps our sensory perceptions can only reach thus far and may never fetch the ‘absolute truth’, if ever there is such a concept. (Goldstein, 2009)
When one ventures beyond the merely scientific and into the world of spirituality and mysticism, one is informed of the ‘illusionary’ nature of human sensory perception. For example, according to the Buddhist view on sensory perception, what we see, hear, etc are a result of conditioning (both as a result of nature and nurture) and thereby skewered. The Buddhist view claims that ‘absolute truth’ is to be discerned as a result of sensory suspension and de-conditioning – say, as it happens during a meditation session. The nature of this ‘absolute truth’ is universal and not merely limited to human sensory capacities. Hence, merely depending on sensory perception to ascertain facts is hazardous to self and society.
Goldstein, E. Bruce (13 February 2009). Sensation and perception. Cengage Learning.ISBN 978-0-495-60149-4. Retrieved 26 March 2011
Pomerantz, James R. (2003): “Perception: Overview”. In: Lynn Nadel (Ed.), Encyclopedia of Cognitive Science, Vol. 3, London: Nature Publishing Group, pp. 527–537