وَإِنْ لَمْ يَكُنْ لَهُ ظَنٌّ: بَنَى عَلَى الْيَقِينِ.
Translation: If one has no stronger judgment, one builds on what is certain.
When probabilities are balanced, certainty lies in the smaller established number. Between three and four, three are definite while the fourth is doubtful; the smaller number is the basis for completion.
The ruling preserves established certainty rather than treating a doubtful rakah as proven.
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Prostrations of Forgetfulness: Causes, Method, Missed Sittings and Doubts
وَإِنْ لَمْ يَكُنْ لَهُ ظَنٌّ: بَنَى عَلَى الْيَقِينِ.
Translation: If one has no stronger judgment, one builds on what is certain.
When probabilities are balanced, certainty lies in the smaller established number. Between three and four, three are definite while the fourth is doubtful; the smaller number is the basis for completion.
The ruling preserves established certainty rather than treating a doubtful rakah as proven.