Reliabilism

Reliabilism is a family of epistemological theories that define justification and knowledge in terms of the reliability of the process by which beliefs are formed. In standard reliabilist accounts, a belief is justified if it is produced by a reliable cognitive process, and knowledge is true belief produced by such a process.

There are externalist and internalist variants. Externalist reliabilism holds that justification does not depend on the subject's internal mental states but on the overall reliability of the process in producing true beliefs across relevant conditions. Internalist variants attempt to tie justification to internal criteria, such as conscious reasoning or accessible reasons, while still appealing to reliability as a virtue of the process.

Common reliable processes include perception, memory, inference, and testimony; the theory emphasizes that reliability is evaluated across the environments in which the process operates, rather than requiring the subject to recognize or justify the process internally.

Criticisms include Gettier-style cases, which show that true beliefs produced by reliable processes can still fail to be knowledge. Externalist reliabilism faces questions about attributing justification to agents who are unaware of the generating process, while internalist critics worry about grounding justification without appealing to process reliability. Proponents respond by refining the notion of reliability, environment sensitivity, and the kinds of processes counted as epistemically relevant.

Relabilism is a major approach in contemporary epistemology, often contrasted with evidentialism and coherentism, and it has influenced discussions of memory, perception, testimony, and even applications in cognitive science and artificial intelligence.