What do you know, really? And how did you arrive at it? These are the two central questions of epistemology, or theory of knowledge, one of the most central branches in philosophy along with metaphysics and ethics. Epistemological views have been elaborated in all philosophical traditions. They divide primarily among so-called rationalist and empiricist theories, the former relying on reason for the justification of beliefs, the latter on the senses.
Skepticism
One way to approach the central questions of epistemology start from skepticism: what do we have reasons to doubt philosophically?
Pretty much everything, says the most radical form of skepticism (Pyrrhonian skepticism), as revived also by Descartes in modern times. The senses prove to be unreliable on many counts, as when we watch a glass of water and we see a straw bent, which is in fact not bent at all. But also reason proves to be unreliable, as when we go through a series of calculations to determine the result of a math exercise, only to realize at the end that we made some mistake along the way – but, where? Memory is also of little comfort, as it often misguides us.
The skeptical solution is to live without the need to know. To Pyrrho, this was also a recipe for happiness, an invitation not to hold dear anything of this world. Unfortunately for him, the proposal did not convince many heads.
Empiricism
Empiricists believe that the senses are the primary source of information for human agency. In their mind, skeptical objections toward the senses can be bracketed by learning how to construe general claims from specific sensorial experiences.
Empiricism has been particularly strong in Western philosophy starting from the the scientific revolution in sixteen and seventeen hundreds, with authors such as Bacon, Locke and Hume. The need to sort out a methodology for the correct formation of general claims starting from particular impressions brought to a refinement of scientific methodology, most especially to the development of inductive reasoning.
An induction is indeed a reasoning, which ends with a general or universal statement, and is prompted by claims regarding particular facts. Hume most famously criticized the possibility of reaching certain conclusions through inductive reasoning, a conclusion which was then picked up by Kant, who attempted to rebut it in a rationalist fashion.
Rationalism
Rationalists such as Kant hold that reason is the primary source of knowledge. The senses, by themselves, could never suggest the existence of a self, a substance, or just about any continuous entity whatsoever.
As empiricists aimed to find out the correct methodology for philosophizing, so rationalists deny that all sorts of claim arrived at through the use of reason ought to be accepted as correct. Thus, for instance, Kant proposed that only claims of a certain form could constitute viable candidates for assessing the ethical worth of an action, and he devised a parallel method also for metaphysical and aesthetic claims.
Introspection
A special place in epistemology occupies knowledge of our own beliefs and sensations, which is achieved through introspection. Descartes’s Meditations on First Philosophy had placed a special weight on introspection: the possibility of human knowledge rested on self-consciousness, the most basic and fundamental of our introspective acts. For Descartes, indeed, introspection was infallible: you cannot make any mistake in knowing your own mind, that is, the mind is transparent to the self that reflects upon it. This myth has been challenged on several counts in modern and contemporary philosophy, not only by Freudian and Lacanian theories of the mind, but also by a number of philosophers who have accounted for different models of the self and self-knowledge.
Further Online Readings
The entry on epistemology at the Stanford Encyclopedia of Philosophy.
The entry on epistemology at the Routledge Encyclopedia of Philosophy.
The entry on epistemology at the Internet Encyclopedia of Philosophy.
The epistemology page, maintained by philosopher Keith de Rose.
The epistemology research guide, maintained by philosopher Keith Korcz.
