Reliabilism

Reliabilism, a category of theories in the philosophical discipline of epistemology, has been advanced both as a theory of knowledge and of justified belief. As a theory of knowledge, reliabilism on one formulation can be roughly stated as follows:

One knows that p (p stands for any proposition--e.g., the sky is blue) if, and only if, (1) one believes that p, (2) p is true, and (3) one has arrived at the belief that p through some reliable process.

As a theory of justified belief, reliabilism can be formulated roughly as follows:

One has a justified belief that p if, and only if, the belief is the result of a reliable process.

Leading proponents of reliablist theories of knowledge and justification have included Alvin Goldman, Marshall Swain, and more recently, Alvin Plantinga. Goldman's article "A Causal Theory of Knowing" (need full reference) is generally credited as being the seminal statement of the theory, though D. M. Armstrong is also regarded as an important source of the theory.

On the classical or traditional analysis of 'knowledge', one must be justified in believing that p in order for that belief to constitute knowledge; the traditional analysis has it that knowledge is no more than justified true belief (see justified true belief analysis). Reliabilist theories of knowledge are sometimes presented as an alternative to that theory: rather than justification, all that is required is that the belief be the product of a reliable process. But reliabilists need not be regarded as alternatives, but instead as further explications: those who offer reliabilist theories of justification further analyze the 'justification' part of the traditional analysis of 'knowledge' in terms of reliable processes.

Some find reliabilism objectionable because it entails externalism, which is the view that one can have knowledge, or have a justified belief, despite not knowing (having "access" to) the evidence, or other circumstances, that make the belief justified. The reliabilist maintains that a belief can be justified, or can constitute knowledge, even if the believer does not know about or understand the process that makes the belief reliable. In defending this view, reliabilists (and externalists generally) are apt to point to examples from simple acts of perception: if I see a bird in the tree outside my window and thereby gain the belief that there is a bird in that tree, I might not at all understand the cognitive processes that explain for my successful act of perception; nevertheless, it is the fact that the processes worked reliably that accounts for why my belief is justified. In short, I find myself with my belief about the bird, and that belief is justified if any is, but I am not acquainted at all with the processes that led to the belief and made me justified in having it. Of course, internalists have answers to such points; see externalism (epistemology).

Another objection to reliabilism, made first to Goldman's knowledge reliable process theory of knowledge and later to other reliabilist theories, is the so-called

Many reliabilists also subscribe to the causal theory of belief.