science

Presumption of regularity

Presumption of regularity is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Presumption of regularity rather than just read about it. In short: The presumption of regularity is a presumption that forms part of the law of evidence of England and Wales. It also plays a role in some other countries.

Key takeaways

Presumption of regularity belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Presumption of regularity to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Presumption of regularity from memory before moving on to harder problems.

Reference excerpt

The presumption of regularity is a presumption that forms part of the law of evidence of England and Wales. It also plays a role in some other countries. It is expressed by the maxim of law omnia praesumuntur rite et solemniter esse acta donec probetur in contrarium, (lit. 'Everything is presumed right and solemn about this act until proven to the contrary'); which may be shortened to omnia praesumuntur rite et solemniter esse acta (lit. 'everything is presumed right and solemn about this act') or omnia praesumuntur rite esse acta (lit. 'Everything is presumed right about this act').

Official actions Where it has been proved that an "official act" has been done, it will be presumed, until the contrary is proved, that the said act "complied with any necessary formalities" and that the person who did it was "duly appointed". This is a presumption of law. The following cases are relevant to this presumption:

R v Gordon (1789) 1 Leach 515, (1789) 1 East PC 315 R v Jones (1806) 31 St Tr 251, (1806) 2 Camp 131 R v Verelst (1813) 3 Camp 432 R v Catesby (1824) 2 B & C 814, (1824) 4 Dow & Ry KB 434, (1824) 2 Dow & Ry MC 278 R v Rees (1834) 6 C & P 606 R v Murphy (1837) 8 C & P 297 R v Townsend (1841) C & Mar 178 R v Newton (1843) 1 C & K 469 R v Manwaring (1856) 26 LJMC 10, (1856) Dears & B 132, (1856) 7 Cox 192 R v Cresswell (1876) 1 QBD 446, (1876) 33 LT 760, (1876) 40 JP 536, (1876) 13 Cox 126 R v Stewart (1876) 13 Cox 296 R v Roberts (1878) 14 Cox 101, (1878) 42 JP 630, (1878) 38 LT 690, CCR Gibbins v Skinner [1951] 2 K.B. 379, [1951] 1 All E.R. 1049, [1951] 1 T.L.R. 1159, (1951) 115 J.P. 360, 49 L.G.R. 713 Campbell v Wallsend Shipway and Engineering Co Ltd [1977] Crim LR 351, DC Dillon v R [1982] AC 484, [1982] 2 WLR 538, [1982] 1 All ER 1017, 74 Cr App R 274, [1982] Crim LR 438, PC Gage v Jones [1983] RTR 508, DC Kynaston v Director of Public Prosecutions, 87 Cr App R 200, DC

Business transactions Where it has been proved that "necessary business transactions" have been carried out, it will be presumed, until the contrary is proved, that the said transactions were carried out in the order (if any) that they are required to be carried out. See Eaglehill Ltd v J Needham (Builders) Ltd [1973] AC 992, HL.

Mechanical contraptions Where it has been proved that a "mechanical device" is normally in "good working order", it will be presumed, until the contrary is proved, that it was in good working order on any relevant occasion. See Tingle Jacobs & Co v Kennedy [1964] 1 WLR 638, CA

In the United States In the United States, the presumption of regularity is a principle of deference that narrows judicial scrutiny over executive decisions. It applies to "a subset of factual disputes about administrative motivations and internal processes".

References

Further reading Best. A Treatise on Presumptions of Law and Fact. 1844. Chapter 2 of Part 2. pp 74 to 86. Best. The Principles of the Law of Evidence. 8th Ed. 1893. Subsection 4 of Section 2 of Part 2 of Book 3. pp 330 to 336. Jones. The Law of Evidence in Civil Cases. 1896. Volume 1. p 55 et seq.

Worked examples

Example 1 — a first encounter with Presumption of regularity

Start with the simplest possible case. Write down what Presumption of regularity claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Presumption of regularity before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Presumption of regularity ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Presumption of regularity

In research: Presumption of regularity appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Presumption of regularity in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Presumption of regularity is common in secondary-school and first-year university syllabi. It links to neighbouring topics Evidence law, so understanding it makes those chapters shorter.
In everyday life: Look for Presumption of regularity outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Presumption of regularity in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Presumption of regularity means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Presumption of regularity out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Presumption of regularity in simple terms?

The presumption of regularity is a presumption that forms part of the law of evidence of England and Wales. It also plays a role in some other countries.

Why does Presumption of regularity matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Presumption of regularity?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Presumption of regularity.