Does one prostrate for forgetfulness merely upon doubt in the prayer?

Question:
May Allah reward you, Honorable Shaykh. This questioner says: Does one prostrate for forgetfulness merely upon doubt in his prayer?

Answer:
Yes, this is one of the causes of the prostration for forgetfulness. There are three causes for the prostration for forgetfulness: either an addition in the prayer, or a decrease in the prayer, or doubt in the count. If one doubts about the number of rak'ahs, and something prevails in his mind, he acts according to his predominant suspicion and relies on his predominant suspicion, and he prostrates for forgetfulness. If nothing prevails in his mind and the two possibilities are equal for him, he builds upon the certainty, which is the lesser number, and completes his prayer, and he prostrates for forgetfulness. Yes.