The answer: He should not pray while in doubt, because the basic presumption is that the time has not begun; one should not depart from that presumption except on the basis of a legally valid justification.

May he pray when he considers it more likely than not that the time has not begun?

The answer: He should not pray, all the more so.

May he pray when he is certain that the time has not begun? The answer: It is not permissible.

Thus, there are three cases in which he should not pray and two in which he may pray, making five cases in all: certainty that the time has begun, and the preponderant likelihood that it has begun. He may pray in these two cases. However, if, in the second case, he later becomes certain that he prayed before the time began, he must repeat the prayer, and the first prayer counts as a voluntary prayer.

The third, fourth, and fifth cases are: doubt as to whether the time has begun, the preponderant likelihood that it has not begun, and certainty that it has not begun. In these cases, he should not pray.

We also learn from the author’s words that preponderant likelihood has a role in acts of worship. Although some acts of worship cannot be performed except on the basis of certainty, many acts of worship are based on preponderant likelihood. Indeed, this is a principle concerning acts of worship: acting upon what is considered more likely than not. Hence, if a person is uncertain about how many units of prayer he has performed, the correct view is that he acts upon what seems more likely to him. The established school holds that he should act only upon certainty (1). Likewise, if he is uncertain about the number of circuits of tawaf or the rounds of sa‘i, he bases his count on what seems more likely to him if one possibility outweighs the other; but if neither possibility outweighs the other, he bases it on certainty.