or a mound of sand that is round and rises above the ground around it; its plural is falak.”

He further says: “Hence the expression, ‘falaka the breast of a young girl—taf līkan and taf allaka,’ meaning that it has become rounded.”

I say: The term “swimming” (sabāḥah) also carries the sense of swift movement, as the lexicographers have noted.

Knowledge of the crescent moon

In the same way, the Lawgiver has made the ruling on the crescent conditional upon actual sighting. He said, “Fast when you see it and break your fast when you see it.” He also said, “We are an unlettered nation; we neither write nor calculate. When you see it, begin the fast, and when you see it, end the fast.” And he said, “Fast from one crescent to the next.”

Those skilled in astronomical computation agree that the precise moment the crescent first appears cannot be fixed by calculation. Although they know that the moon’s light is borrowed from the sun, and that when the two discs coincide at conjunction no light is visible, and that once the moon parts from the sun it begins to shine, the utmost their calculations can yield—assuming their ephemerides and corrections are accurate—is the moon’s distance from the sun at sunset. They call this the science of “tables and corrections,” for they take the moon’s greatest and least positions and derive its mean, then compute on that basis.

Even if they succeed in estimating its altitude at sunset, this in itself neither proves nor disproves the possibility of sighting, for sighting is a sensory matter influenced by many factors: the clarity or turbidity of the atmosphere, the elevation or depression of the viewing point, and the sharpness or dullness of eyesight. Thus, one person may fail to see it while another with keener vision does see it, and it may be visible from a high vantage point yet invisible from a low-lying one.