Free tool · Legal Reasoning and Argument
Toulmin Argument Builder: Claim, Grounds, Warrant, Backing and Rebuttal
The Toulmin model describes an argument as a claim, supported by grounds (facts or evidence), linked to the claim by a warrant (the general rule or principle that makes the step legitimate), which needs backing (its source), and is qualified in strength and open to rebuttal. Most weak legal arguments are weak in a predictable way: a part is missing, and most often it is the warrant. A good legal argument states the rule that connects its facts to its conclusion, says where the rule comes from, admits its own limits with a measured qualifier and says when the claim would fail and why those conditions are absent.
Tool · Argument Builder (Toulmin)
All six parts are present and sound.
Good: There is a claim: a conclusion that the reader is asked to accept.
Good: There are grounds: facts or evidence that the claim rests on.
Good: There is a warrant: the rule or principle that connects the grounds to the claim.
Good: The warrant says something more general than the claim, as a warrant should.
Good: The warrant speaks to the kind of facts in the grounds, so it connects them to the claim.
Good: The warrant has backing: a statute, case or principle that shows it is the law, or why it is sound.
Good: The qualifier shows the strength of the claim and is measured.
Good: The argument recognises the conditions under which the claim fails. This is what makes it credible and prepares you for the other side.
As one sentence
Because the customer slipped on a wet floor that had no warning sign, and the floor had been wet for forty minutes, and since a business that lets a hazard remain for longer than a reasonable time without warning breaches its duty to take reasonable care of visitors (the duty of care owed by occupiers to lawful visitors, and the case law on how long a hazard may remain before the occupier is taken to know of it), it follows that Very probably, the shop is liable for the customer’s broken wrist, unless the customer was not looking where she was going to a degree that breaks the chain of causation, or the spill happened moments earlier.
Fill in the six parts of a Toulmin argument, claim, grounds, warrant, backing, qualifier and rebuttal, and see which parts are missing or weak, and how the argument reads as one sentence. The checks look for gaps (above all a missing warrant), absolutes, restating the claim as the warrant and bare assertions. They cannot tell whether the argument is right. Use invented facts. Runs in your browser; nothing is stored or sent.
How to use it
- Write the claim you want accepted.
- Add the grounds, the warrant and the backing for the warrant.
- Add a qualifier and the rebuttal.
- Read the checks, fix the gaps and read the argument back as one sentence.
Common questions
What is a warrant?
The rule or principle that links the grounds to the claim. It is general: it would support other, similar claims, and not only this one.
Why is a qualifier useful?
Because legal conclusions are rarely certain. A measured qualifier such as ‘probably’ is more credible than an absolute, and it tells the reader how strong the claim is.
Does the tool tell me whether my argument is right?
No. It checks structure, such as whether a warrant is missing or restates the claim. Whether the argument is correct on the law depends on the authority and the facts.
Learn the law behind the tool
This tool is part of our Legal Reasoning and Argument course, with lectures, concept maps, flashcards, interactive exercises and a capstone case. Legal Reasoning and Argument: Building an Argument.
More free law tools
General information, simplified, mainly on American law, not legal advice. States and countries differ, and real cases turn on facts that a tool cannot capture.