They said:

“Furthermore, whether a matter is certain or probable is relative to the circumstances of those who hold the belief; it is not a property of the proposition itself. A person may be certain of things that he knows self-evidently, or through reports whose truth is established for him, while someone else has neither certain nor probable knowledge of them. A person may also be intelligent, sharp-minded, and quick to understand, grasping truths with certainty that another person cannot even conceive of and has neither certain nor probable knowledge of.

“Certainty and probability thus depend on the evidence that has reached a person and his ability to reason from it. People differ in both respects. Whether a matter is certain or probable is therefore not an inherent property of the disputed proposition, such that one could say, ‘Everyone who disagrees with it has contradicted something certain.’ Rather, it describes the condition of the person examining the matter, reasoning about it, and holding the belief. This varies from one person to another. It is thus clear that this distinction does not hold consistently in either direction.”

Some of them drew a third distinction, saying:

“Fundamental matters are those known through reason. Every question concerning knowledge that reason can apprehend independently is therefore a fundamental matter, disagreement with which renders a person an unbeliever or a transgressor. Subsidiary matters are those known through revelation.”

They said: “The first category includes questions concerning the divine attributes and decree; the second includes questions concerning intercession and the departure from Hell of those who committed major sins.”