if his mistakes and lapses of memory outweighed—or were at least equal to—his accuracy and precision, he is classed as having an unsound memory. Accordingly, only the reports in which he is demonstrably accurate and precise, especially when those are numerous, may be relied upon.

Ruling on a narrator with an unsound memory

If this weak memory was his constant state at all times throughout his life, his ḥadīth is not taken into consideration. Some ḥadīth critics even regard such transmissions as falling under the heading of anomalous reports.

The “confused” narrator (mukhta​lat)

Should the poor memory arise later from a specific cause—such as senility, loss of eyesight, or the disappearance of his notebooks—he is termed mukhta​lat, “one who became confused.”

Ruling on the mukhta​lat narrator

Whatever he transmitted before the onset of confusion must be kept separate from what he narrated afterwards. When it cannot be determined whether a particular report came from the earlier or the later period, judgment is suspended; and if the matter remains uncertain, the same suspension applies.