cases began to arise in which a deceased person left both a grandfather and siblings, and they discussed these. Likewise, the two cases known as the ʿUmariyyatān arose, and they discussed them.

Yet the science of inheritance is a specialist discipline, unfamiliar even to many jurists. For scholars versed in it, it constitutes certain, conclusively established knowledge of jurisprudence, whereas most people associated with scholarship—let alone the general public—have neither certain nor probable knowledge of it. This resembles medical findings established through experience: those who have tested them and those practitioners familiar with them know them, whereas most people engaged in other disciplines—let alone the general public—have neither certain nor probable knowledge of them.

Indeed, menstruation is among the most difficult topics of jurisprudence in the book of purification, with its well-known subsidiary questions and disagreements. Nevertheless, most religious rulings concerning women’s conduct during menstruation are known. Someone who undertakes to give people fatwas gives them known, agreed-upon rulings a hundred times before giving them a ruling based on probability once, even though most people do not know the rulings on menstruation. As for the matters over which jurists disagree—its minimum and maximum duration, the latest and earliest ages at which it occurs, and questions concerning a woman uncertain about her menstrual state—these are among the rarest situations encountered. When does one find a woman whose menstruation lasts only a single day? There are only very few accounts of this, while it is known that the great majority of the daughters of Adam menstruate, as stated by