The greatest challenge of rationalists is that they seem incapable to allow us gain contingent truths, truths which pertain to the world. Critics of rationalists argue that while reason allows us to have knowledge which is indubitable, they are limiting in nature and do not tell us anything of interest about the world. For instance, it is inconceivable that rationalists can obtain knowledge that Mount Everest is the tallest mountain on Earth through pure reasoning. Some rationalists advance their argument through the use of an omnipotent God. They argue that since God is all powerful, the world He created must have some underlying order and it is the best possible world. Human minds, equipped with the faculty of reasoning can discern contingent truths. Unfortunately, this view is challenged on the ground that existence of God is not established and even if this all powerful omnipotent being existed, He might not play the role the rationalists describe.
Another school of foundationalism, empiricism, argues that experience is the primary source of knowledge. Hume, the great British empiricists, argues that there exist ideas and impressions in our mind. Impressions can come from sense experience or mental experience and it is through impressions that we can form ideas. For instance, when one sees a red circle, one has the sense experience of seeing something round and red in color. The faculty of cognition will make a copy of this red, round sense experience in the memory, forming the idea of ‘red circle’ such that he will recognize it when he next encounters it. Empiricists claim that this idea or concept formation is how we acquire knowledge.
Empiricists pride themselves with the indubitability of sense data. According to them, sense experience is indubitable. One cannot doubt the slightest that one is having the sense experience of looking at a piece of paper with words on it. It could be that an evil genius was deceiving him or a computer stimulating his brain, feeding him the sensation, or it could be a dream (as Descartes presented in his Meditation), but the very fact that one having this paper-like sensation is indubitable. However, many critics argue that while sense experience is indubitable, it remains as a bundle of perceptions until one interprets and categorizes it meaningfully. But if one attempts to interpret and categorize it, then one faces the possibility of error and thus uncertainty. Therefore, while sense experience provides knowledge of the world, there cannot be absolute certainty.
From the above illustrations, it is obvious that neither empiricists nor rationalists are able to provide a theory of knowledge which can satisfactorily provide us a mean of acquiring knowledge of the world, contingent truths, with certainty. Besides, the very idea of self-justifying, basic, indubitable beliefs have been under much attack. It seems that the notion of indubitable beliefs suggest that we can form our knowledge on the basis of a set of arbitrary beliefs (like clear and distinct ideas). Even if these basic beliefs are to gain general acceptance, it seems like it is the general acceptance which makes them self-justifying.
When we look at the world around us, the progress human civilization has made in the past few centuries – the advancement of natural sciences, space exploration, biomedicine, social sciences like economics and geography, none of them are based on a set of indubitable beliefs. Instead, they are subjected to constant revision. Three hundred years ago Newton formulated the law of gravitation; the beginning of twentieth century saw the great scientist Einstein rejecting it with his Theory of Relativity. Adam Smith, the father of modern economics established that a society is best when all individuals think only for themselves. In the 1950s, John Nash proposed otherwise. In his game theory, he argued that the society is best when all individuals think for themselves and the society. This view has gained wide acceptance and is now seen as a substitute for the former.
The foundationalists’ enterprise does not fit the need of the society. It is coherentism which is the accepted model of knowledge, not by epistemologists, but by practitioners of social and natural sciences. The coherentists accept that a belief is justified so long as it coheres well with a web of established beliefs (in this case, the objective set of established beliefs by the society) and support it. Each belief is not justified by one other belief, but all the immediate beliefs which are linked to it. All beliefs are subjected to revision though those beliefs which are located at the side of the web will be revised more easily than those at the center of the web. For instance, Newton’s law of gravity is a belief which is well justified by many of the beliefs in this established web and those located near the center. In order to revise it, there must be a great amount of evidence which will overwrites those justifying beliefs. It is the overwhelming evidence of the Relativity Theory that Newton’s law of gravity is revised and removed.
In conclusion, progress cannot be made if we insist that knowledge be based on bedrock of indubitable belief. The field of mathematics, which is based on a set of axioms from which all other theorems can be proven, is a good illustration of a field of knowledge which can be formed from foundationalists’ principles. It is eternal and unchanging and certain. However, for progress to be achieved, we cannot rely solely on mathematical knowledge. Social and natural sciences are founded on the principles of coherentism, where beliefs can be revised. Even the strongest belief can be revised if there are sufficient beliefs to do so. Therefore, it is my contention that if progress is to be achieved, we cannot insist on knowledge that is founded on bedrock of indubitable beliefs.
