Evidence

Evidence for a proposition is what supports the proposition. It is usually understood as an indication that the proposition is true. The exact definition and role of evidence vary across different fields. In epistemology, evidence is what justifies beliefs or what makes it rational to hold a certain doxastic attitude. For example, a perceptual experience of a tree may serve as evidence to justify the belief that there is a tree. In this role, evidence is usually understood as a private mental state. In phenomenology, evidence is limited to intuitive knowledge, often associated with the controversial assumption that it provides indubitable access to truth.

In the philosophy of science, evidence is material that confirms or disconfirms scientific hypotheses, acting as a neutral arbiter between competing theories. Measurements of Mercury's "anomalous" orbit, for example, are seen as evidence that confirms Einstein's theory of general relativity. Philosophers of science tend to understand evidence not as mental states but as observable physical objects or events, secured by following the scientific method. The problems of underdetermination and theory-ladenness are two obstacles that threaten to undermine the role of scientific evidence.

In law, evidence is information to establish or refute claims relevant to a case, such as testimony, documentary evidence, and physical evidence.^[1]

The relation between evidence and a supported statement can vary in strength, ranging from weak correlation to indisputable proof. Theories of the evidential relation examine the nature of this connection. Probabilistic approaches hold that something counts as evidence if it increases the probability of the supported statement. According to hypothetico-deductivism, evidence consists in observational consequences of a hypothesis. The positive-instance approach states that an observation sentence is evidence for a universal statement if the sentence describes a positive instance of this statement.