Pacisco\Toulmin_Model\Warrant

The warrant is the justification for asserting the claim given the grounds; the middle term.  It is often a principle or rule.

… To present a particular set of data as the basis for some specified conclusion commits us to a certain step; … we must bring forward not further data, … but propositions of a rather different kind: rules, principles, inference-licences or what you will, instead of additional items of information.  Our task is no longer to strengthen the ground on which our argument is constructed, but rather to show that, taking these data as a starting point, the step to the original claim or conclusion is an appropriate and legitimate one.  At this point, therefore, what are needed are general, hypothetical statement, which can act as bridges and authorise the sort of step to which our particular argument commits us.  These may normally be written very briefly (in the form of ‘If D, then C’); but for candour’s sake, they can profitably be expanded, and made more explicit: ‘Data such as D entitles one to draw the conclusions, or make claims, such as C’, or alternatively ‘Given data D, one may take it that C.’

Propositions of this kind I shall call warrants ( W ), to distinguish them from both conclusions and data. …

Toulmin 2003, pp. 90-1.

In Pacisco, a warrant consist of a simple claim, e.g:

“The age of criminal responsibility in England and Wales is 10 years old.”

In this case, if the grounds of the argument had included evidence that someone was older than 10 years of age, a claim that they had criminal responsibility would be substantiated.

“Coomassie G-250 dye stains only protein.”

In this case, if the grounds of the argument included evidence that “Coomassie G-250 dye staining was observed.” a claim that protein was present would be substantiated.

In some cases a warrant, implied and never explicitly stated in everyday conversation, may take some teasing out and may seem like a pedantic triviality when it is expressed.