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Presumption

Presumption 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 rather than just read about it. In short: In law, a presumption is an "inference of a particular fact". There are two types of presumptions: rebuttable presumptions and irrebuttable (or conclusive) presumptions.

Key takeaways

  • Presumption 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 to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Presumption from memory before moving on to harder problems.

Reference excerpt

In law, a presumption is an "inference of a particular fact". There are two types of presumptions: rebuttable presumptions and irrebuttable (or conclusive) presumptions. A rebuttable presumption will either shift the burden of production (requiring the disadvantaged party to produce some evidence to the contrary) or the burden of proof (requiring the disadvantaged party to show the presumption is wrong); in short, a fact finder can reject a rebuttable presumption based on other evidence. Conversely, a conclusive/irrebuttable presumption cannot be challenged by contradictory facts or evidence. Sometimes, a presumption must be triggered by a predicate fact—that is, the fact must be found before the presumption applies.

History The ancient Jewish law code, the Talmud, included reasoning from presumptions (hazakah), propositions taken to be true unless there was reason to believe otherwise, such as "One does not ordinarily pay a debt before term." The same concept was found in ancient Roman law, where, for example, if there was doubt as to whether a child was really the issue of someone who had been left money in a will, the presumption was in favour of the child. Medieval Roman and canon law graded presumptions according to strength: light, medium or probable, and violent. These gradings and many individual presumptions were taken over into English law in the seventeenth century by Edward Coke.

Specific presumptions

A number of presumptions are found in most common law jurisdictions. Examples of these presumptions include:

The presumption of death. A person who has been absent for seven years without explanation and "gone to parts unknown" is presumed dead at common law. The time period it takes for the presumption to arise has often been modified by statute. The presumption of sanity. A person who faces criminal trial is presumed sane until the opposite is proved. Similarly, a person is presumed to have testamentary capacity until there is evidence to undermine that presumption. The presumption of innocence, which holds that the prosecution bears the burden of proof in a criminal case with the result that the accused may be acquitted without putting forward any evidence. The presumption of legitimacy or presumption of paternity, which presumes that a husband is the legal father of a child born to his wife during the marriage, or within nine months after the marriage is ended by death, legal separation, or divorce. Some jurisdictions also hold that a presumption of paternity arises when a father accepts a child into his home, or publicly represents that he is the child's father. A presumption of survivorship has referred to a number of different presumptions. The term is sometimes used to refer to presumptions that one or another of two persons lived the longer when they died together in the same accident. The presumption that two or more people who establish a joint account intend for the survivors to have the assets put into the fund upon the death of one of the joint account holders has also been called the "presumption of survivorship". The presumption of mailing presumes that a properly addressed letter delivered to the post office or a common carrier was in fact delivered and received by the addressee. The presumption of fraud or undue influence arises where a person in a position of trust over another, such as a guardian or the holder of a power of attorney applies the other person's assets to their own benefit. The presumption of validity is another way of expressing a burden of proof: the official acts of courts are presumed valid, and those who would challenge them must overcome this presumption. This is also termed the presumption of regularity. The presumption of advancement in relation to transfers from husbands to wives and from fathers to children. In commercial contracts, there is a presumption that parties to a contract intend all disputes between them to be determined within the same forum. This presumption is also known as "one-stop adjudication" and reflects the belief that contracts are entered into by rational business parties. A German Bundesgerichtshof (Federal Court of Justice) decision made on 27 February 1970 thought there was "every reason to presume that reasonable parties will wish to have the relationships created by their contract and the claims arising therefrom ... decided by the same tribunal and not by two different tribunals", and the Federal Court of Australia in Comandate Marine Corp v Pan Australia Shipping Pty Ltd. (2006) referred to a "sensible commercial presumption that the parties did not intend the inconvenience of having possible disputes from their transaction being heard in two places". The House of Lords in Premium Nafta Products Ltd (20th Defendant) and Ors v. Fili Shipping Company Ltd and Ors (2007) noted that "this approach to the issue of construction is now firmly embedded as part of the law of international commerce" and endorsed a ruling the Court of Appeal made on this basis, stating that this presumption "must now be accepted as part of our [England and Wales] law too". In the law of the United States, the presumption of constitutionality presumes that all statutes are drafted in accordance with Federal and state constitutional requirements. The party challenging the constitutionality of a statute bears the burden of proof, and any doubts are resolved against that party. If there are two reasonable interpretations of a statute, one of which is constitutional and the other not, the courts choose the path that permits upholding the statute.

Conclusive (irrebuttable) presumption

A conclusive presumption, also known as an irrebuttable presumption, is a type of presumption used in several legal systems. In English law, a conclusive presumption is a presumption of law that cannot be rebutted by evidence and must be taken to be the case whatever the evidence to the contrary. For example, a child below the age of criminal responsibility is presumed to be incapable of committing a crime.

Australia In Australian law, it is a conclusive presumption that no child under the age of 10 can be held responsible for criminal action. This presumption exists to protect children by acknowledging that they do not have sufficient development to understand the gravity and consequences of committing a criminal act.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Presumption

Start with the simplest possible case. Write down what Presumption 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 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 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

In research
Presumption 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 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 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Evidence law, Legal doctrines and principles, so understanding it makes those chapters shorter.
In everyday life
Look for Presumption 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 in 20 minutes

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

Frequently asked questions

What is Presumption in simple terms?

In law, a presumption is an "inference of a particular fact". There are two types of presumptions: rebuttable presumptions and irrebuttable (or conclusive) presumptions.

Why does Presumption 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?

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.

Tags

  • Evidence law
  • Legal doctrines and principles

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