Similarities and differences between an evidentialist justification and a reliabilist justification for a belief?

Question

Evidentialism

Evidentialism in epistemology is defined by the following thesis about epistemic justification:

(EVI) Person S is justified in believing proposition p at time t if and only if S’s evidence for p at t supports believing p.

As evidentialism is a thesis about epistemic justification, it is a thesis about what it takes for one to believe justifiably, or reasonably, in the sense thought to be necessary for knowledge. Particular versions of evidentialism can diverge in virtue of their providing different claims about what sorts of things count as evidence, what it is for one to have evidence, and what it is for one’s evidence to support believing a proposition. Thus, while (EVI) is often referred to as the theory of epistemic justification known as evidentialism, it is more accurately conceived as a kind of epistemic theory. In this light, (EVI) can be seen as the central, guiding thesis of evidentialism. All evidentialist theories conform to (EVI), but various divergent theories of evidentialism can be formulated.

Source: https://iep.utm.edu/evidentialism/

Reliabilism

Reliabilism encompasses a broad range of epistemological theories that try to explain knowledge or justification in terms of the truth-conduciveness of the process by which an agent forms a true belief. Process reliabilism is the most common type of reliabilism. The simplest form of process reliabilism regarding knowledge of some proposition p implies that agent S knows that p if and only if S believes that p, p is true, and S’s belief that p is formed by a reliable process. A truth-conducive or reliable process is sometimes described as a belief-forming process that produces either mostly true beliefs or a high ratio of true to false beliefs. Process reliabilism regarding justification, rather than knowledge, says that S’s belief that p is justified if and only if S’s belief that p is formed by a reliable process. This article discusses process reliabilism, including its background, motivations, and well-known problems. Although the article primarily emphasizes justification, it also discusses knowledge, followed by brief descriptions of other versions of reliabilism such as proper function theory, agent and virtue reliabilism, and tracking theories.

Source: https://iep.utm.edu/reliabilism/

Suppose that person S believes proposition p.

• If S has an evidentialist justification E for p, does it follow that S also has a reliabilist justification R for p?
• If S has a reliabilist justification R for p, does it follow that S also has an evidentialist justification E for p?
• Generally speaking, what similarities and differences can there be between justifications E and R?

Answer 1

To take a stab at an answer, responding to each question in turn:

1. This likely depends on the exact formulations of reliabilism and evidentialism involved. If an evidentialist theory does not specify that the quality of evidence for a belief p depends on S's knowledge or belief about the quality of evidence S has, rather than the evidence simpliciter, such a theory could depart from reliabilism. For example, the gorilla basketball video. Most people, on first viewing, would endorse the proposition 'there was no person in a gorilla suit,' and it seems to me the evidence they have would support that belief on some evidentialist theories. However, someone with knowledge of how focused attention occludes or can occlude peripheral awareness could know, after watching the video, that the evidence available to them is not likely to be sufficiently exhaustive to motivate belief on a reliabilist view, as an eyewitness to a crime might frustrate police officers by not being confident in their recollection of what occurred. This is, to be fair, splitting hairs, and I think both evidentialism and reliabilism could be specified such that what counts as evidence is all and only that formed by a reliable process (such that, for example, a hallucination would not count as evidence for believing in the content of a hallucination).
2. This, as with 1, depends much on how the specific theories are formulated and what counts as evidence. If, as above, justified beliefs about the belief-formation process are part of the evidence for any p, then evidentialism and reliabilism would seem to converge. Even then, maybe, if S encountered a piece of evidence unimplicated in any belief-formation process that S has available to them then they might diverge. Maybe God could do it; if S had a mystical experience in which God, to S's seeming, disclosed himself to S and this experience was nothing like any other that S has experienced, this might be evidence of some kind without participating in any belief-formation processes that S was used to relying on to evaluate evidence. If so, evidentialism and reliablism might diverge, though the exact formulation of each which still bear on the question. If S could believe in God's existence because, per hypothesis, God is real and S's process for ascertaining his existence is a reliable one independent of S's justified belief that it is a reliable process, then they might again converge. However, still with the hypothetical of God being real, S might conclude that the evidence of the mystical experience is insufficient to believe in God's existence and so not believe in it on an evidentialist view, despite it in fact being the case that the kind of mystical experience S had was in fact a reliable belief-forming process, unbeknownst to S.
3. Much, as above, seems to depend on the formulations involved, but it seems to me that the difference is one of locating the source of epistemic grounding for justification. Under an evidentialist view, what grounds justified belief in p is the evidence that S has for p, while reliablism holds that what grounds justified belief is not the evidence that S has for p, per se, but either is grounded by the belief-forming process that led to S believing in p being a reliable one or is grounded by the evidence that S has for the belief-formation process that leads to S believing p. It could be the case that the belief-formation process that leads S to p is an evidentialist one; likewise, S's commitment to evidentialism could lead them to reliablism. In each case, S would be by strong rational compulsion led, it seems to me, insofar as evidentialism and reliabilism are each true; or, as the case may be, as they are evidently reliable.

This is, though, just a stab.