presumption: one construct, many systems

In statistical hypothesis testing, the null hypothesis plays the role of a presumption: it is the default state of the world that the analyst retains unless the observed data are improbable enough under it to justify rejection. Neyman and Pearson's 1933 theory formalised this as a decision rule that controls the risk of wrongly rejecting a true null, placing the burden on the evidence to overcome the default. Their paper is the earliest source cited on this page, but the presumption-and-burden idea is older in law and rhetoric, so its place here is not a claim that statistics coined the construct. The construct is the same default-until-displaced logic, expressed in the mathematics of error rates.[1]

Unit

The default hypothesis retained pending sufficient evidence to reject it

Recovery means

Not applicable

Measured by

Quantified by the significance level and power that govern when the default is rejected

In argumentation and informal logic, a presumption is a provisional standing granted to a claim that lets it be accepted without proof until someone raises a sufficient objection, which is why presumption and burden of proof are treated as two sides of one device. Walton analyses how presumptions allocate the obligation to act or speak in a dialogue, so the party without the presumption carries the burden of advancing reasons. The referent is a procedural default in reasoned exchange, the same burden-shifting construct that governs legal presumptions and statistical null hypotheses, realised in the rules of dialogue rather than a courtroom or a dataset.[2]

Unit

A provisionally accepted claim that shifts the burden onto its challenger

Recovery means

Not applicable

Measured by

Characterised by what grants the presumption and what weight of objection is needed to defeat it

In the law of evidence, a presumption is a rule that directs the fact-finder to take a particular fact as established once a basic fact is proved, unless the opposing party produces sufficient evidence to displace it. Rebuttable presumptions (of innocence, of legitimacy, of death after long absence) allocate the burden of proof by fixing a default that holds until it is challenged, as Munday sets out alongside the burden of proof. The referent is a burden-shifting default in adjudication: the same logical device that, in statistics, retains a null hypothesis until the data overturn it, and in argumentation, settles who must speak first.[3]

Unit

A default fact that stands until contrary evidence is produced

Recovery means

Not applicable

Measured by

Operationalised by what basic fact triggers it and how much contrary evidence is needed to rebut it