donkey. If the water has changed because of this dung, doubt arises as to whether it is impure or pure.

It is then said: Proceed on the basis of certainty. What is certain is that it is tahūr (pure and purifying), so purify yourself with it; there is no harm in doing so.

The same applies when there is doubt about the impurity of something other than water.

For example, a man has a garment and doubts whether it is impure. The basic presumption is purity until he knows of its impurity.

Likewise, if he has a sheepskin and doubts whether it is the skin of an animal that was lawfully slaughtered or the skin of carrion, the more likely assumption is that it is the skin of an animal that was lawfully slaughtered, and it is therefore pure.

Similarly, if, when intending to pray, he doubts whether the ground is impure or pure, the basic presumption is purity.

An example of doubt concerning purity is when one has impure water whose impurity he knows; then, upon returning to it, he doubts whether its change has disappeared or not. It is then said: the basic presumption is that the impurity remains, so he should not use it.

He proceeds on the basis of certainty, …

His statement, “He proceeds on the basis of certainty”: certainty is that which admits of no doubt. The evidence for this in the reports is the hadith of Abdullah ibn Zayd (may Allah be pleased with him): a man complained to the Prophet (peace and blessings be upon him) that he felt something in his stomach and was uncertain whether anything had come out of him or not. He said: “He should not leave until he hears a sound or detects an odor.” (1) The Prophet (peace and blessings be upon him) thus instructed him to proceed on the basis of the original state, namely, the continuance of