Certainty is a firm conviction that conforms to reality, and the accepted position is that a report(1) transmitted through tawātur(2) produces necessary knowledge—the kind that forces itself upon a person so that he cannot possibly repel it(3).
Some have claimed that it yields knowledge only through inference, but this view carries no weight. Knowledge derived from tawātur(4) is attained even by those who lack the capacity for analytical reasoning—such as the average layperson—because reasoning(5) is the ordering of established or conjectural premises in order to reach further truths or assumptions, and the layperson is not equipped for that. If tawātur knowledge were merely inferential, it would never reach such people.
[The difference between necessary and inferential knowledge]
From this explanation(6) the distinction between necessary knowledge and inferential knowledge has become clear, since(7) necessary knowledge imparts certainty without recourse to inference, whereas inferential knowledge does so only by means of inference. Moreover, necessary knowledge reaches every listener, while inferential knowledge is acquired solely by those who possess the aptitude for reasoning.