---
title: "Evidence"
chunk: 3/5
source: "https://en.wikipedia.org/wiki/Evidence"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T09:55:48.385077+00:00"
instance: "kb-cron"
---

==== In epistemology ====
The guiding intuition within epistemology concerning the role of evidence is that it is what justifies beliefs. For example, Phoebe's auditory experience of the music justifies her belief that the speakers are on. Evidence has to be possessed by the believer in order to play this role. So Phoebe's own experiences can justify her own beliefs but not someone else's beliefs. Some philosophers hold that evidence possession is restricted to conscious mental states, for example, to sense data. This view has the implausible consequence that many of simple everyday-beliefs would be unjustified. The more common view is that all kinds of mental states, including stored beliefs that are currently unconscious, can act as evidence. It is sometimes argued that the possession of a mental state capable of justifying another is not sufficient for the justification to happen. The idea behind this line of thought is that justified belief has to be connected to or grounded in the mental state acting as its evidence. So Phoebe's belief that the speakers are on is not justified by her auditory experience if the belief is not based in this experience. This would be the case, for example, if Phoebe has both the experience and the belief but is unaware of the fact that the music is produced by the speakers.
It is sometimes held that only propositional mental states can play this role, a position known as "propositionalism". A mental state is propositional if it is an attitude directed at a propositional content. Such attitudes are usually expressed by verbs like "believe" together with a that-clause, as in "Robert believes that the corner shop sells milk". Such a view denies that sensory impressions can act as evidence. This is often held as an argument against this view since sensory impressions are commonly treated as evidence. Propositionalism is sometimes combined with the view that only attitudes to true propositions can count as evidence. On this view, the belief that the corner shop sells milk only constitutes evidence for the belief that the corner shop sells dairy products if the corner shop actually sells milk. Against this position, it has been argued that evidence can be misleading but still count as evidence.
This line of thought is often combined with the idea that evidence, propositional or otherwise, determines what it is rational for us to believe. But it can be rational to have a false belief. This is the case when we possess misleading evidence. For example, it was rational for Neo in the Matrix movie to believe that he was living in the 20th century because of all the evidence supporting his belief despite the fact that this evidence was misleading since it was part of a simulated reality. This account of evidence and rationality can also be extended to other doxastic attitudes, like disbelief and suspension of belief. So rationality does not just demand that we believe something if we have decisive evidence for it, it also demands that we disbelieve something if we have decisive evidence against it and that we suspend belief if we lack decisive evidence either way.

==== In phenomenology ====
The meaning of the term "evidence" in phenomenology shows many parallels to its epistemological usage, but it is understood in a narrower sense. Thus, evidence here specifically refers to intuitive knowledge, which is described as "self-given" (selbst-gegeben). This contrasts with empty intentions, in which one refers to states of affairs through a certain opinion, but without an intuitive presentation. This is why evidence is often associated with the controversial thesis that it constitutes an immediate access to truth. In this sense, the evidently given phenomenon guarantees its own truth and is therefore considered indubitable. Due to this special epistemological status of evidence, it is regarded in phenomenology as the basic principle of all philosophy. In this form, it represents the lowest foundation of knowledge, which consists of indubitable insights upon which all subsequent knowledge is built. This evidence-based method is meant to make it possible for philosophy to overcome many of the traditionally unresolved disagreements and thus become a rigorous science. This far-reaching claim of phenomenology, based on absolute certainty, is one of the focal points of criticism by its opponents. Thus, it has been argued that even knowledge based on self-evident intuition is fallible. This can be seen, for example, in the fact that even among phenomenologists, there is much disagreement about the basic structures of experience.