In the classical Hindu schools of thought that deal with epistemology, various sources of knowledge are identified. The primary sources are perception, inference, and testimony. Other processes have also been identified but are either reducible to one or more of the widely accepted sources such as perception and inference or are considered not truth-conducive. The Cārvāka materialist school was one of the proponents of Skepticism. They recognized perception as a knowledge source but not inference nor any other candidate. Inference depends upon generalizations which outstrip perceptual evidence. Cārvāka claims that no one can know that. That which we take to be the result of a genuine inference may turn out to hinge on a fallacy. Similarly, testimony is also no good since it presupposes that any speaker would tell the truth and thus is subject to the same criticism of lack of evidence. For this school, our only channels of knowledge are our sense perceptions. Everything else, they contended, is only inference which is not always reliable. Like Hume, they attacked inductive reasoning, questioning our logical right to extrapolate from what we know to be true, and generalize on the basis of particular observations. A different kind of skepticism that is broader in scope is not restricted to questioning inference alone. Perception, it is pointed out can also mislead us, given that the perceptions are dependent on our senses. It is clear that information acquired through our sense organs is not always a hundred percent reliable since the senses can create illusion, whether optical, auditory, olfactory, gustatory, or tactile. Given that our sensory perceptions are determined by the kind of bodies--cerebral physiology--we happen to possess, all human knowledge is ultimately a function of our brain chemistry. No matter what or how the external world of reality is, the phenomenal world--as Kant was to remind us centuries later--is different from the noumenal world. This leads us to the conclusion that what we call objective knowledge is actually species-subjective.
Radical skepticism is one of the many kinds of philosophical skepticism, which pertains to the idea that knowledge is quite likely impossible. A radical skeptic maintains that all of our beliefs are subject to doubt, the most famous illustration of this being the Brain-in-a-vat hypothesis (BIV). In popular entertainment, the BIV hypothesis is best depicted in the film The Matrix. The film encourages one to imagine that our lives and the reality that we perceive are a computer generated simulation. Since it is impossible to know the difference between a reality that is real and a reality that is “the matrix” with absolute certainty, we can suppose that we cannot really “know” that our reality is in fact real.
This radical skepticism has often been compared to the Hindu and Buddhist philosophical concept of 'māyā '. The concept of māyā , or illusion of knowledge has been variously defined by the different schools. Shankara, for instance, expounded on the idea of māyā as the appearance which veils the true nature of things. In his famous analogy, the ignorant person mistakes a rope for a snake. Gaudapada treats life as a waking dream, and contends that world exists only in the mind of Man. This illusion, called māyā , gives rise to forms which need names, thus offering our minds a semblance of objective reality. Many philosophies and religions seek to "pierce the veil" of māyā in order to glimpse the transcendent truth from which the illusion of a physical reality springs.
While the Advaitin maintains that Māyā is the veiling of the Cosmic Spirit or Brahman, and the epiphany realisation of this fact is the road to nirvana or salvation, I wish to give a slightly different interpretation. I posit that māyā is not a veil to be pierced but the intrinsic impossibility to know anything about the world around us. Radical skepticism seems excessive, and critics are right to point out that we can't live as skeptics in our normal lives. It may well be impossible to ever refute radical skepticism but struggling with the issue helps illuminate the nature of knowledge itself.
References:
- http://plato.stanford.edu/entries/epistemology-india
- http://www.utm.edu/staff/jfieser/class/120/6-knowledge.htm
- http://www.hinduwebsite.com/maya.asp
p.s.- This is an assignment that I submitted to Coursera for my Introduction to Philosophy