Errors in proof, and the close of the poem

An error in a demonstration, wherever it is found, lies in the matter or in the form. The first is in the wording, like equivocation, or like taking as distinct what is synonymous; and in the meanings, through a false premise being confused with a true one — so understand what is said:

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like treating the accidental as the essential, or taking the conclusion as one of the premises, or judging the genus by the judgement of the species, or treating the uncertain as certain. The second is like leaving its figures, or leaving out a condition of producing from its completeness.

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This completes the intended aim among the mothers of praiseworthy logic. By the praise of the Lord of the daybreak, what I sought from the science of logic is finished. The lowly, needy servant put it in verse, in need of the mercy of the great, mighty Master: al-Akhḍarī, ʿAbd al-Raḥmān, hoping from his generous Lord

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for forgiveness that covers all sins and lifts the veil from hearts, and that He reward us with the high Garden, for He is the most generous of those who give.

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Be lenient, my brother, with the beginner, and be a sincere helper in setting right what is wrong. Set right what is wrong after reflection, and do not change things on first sight, for it has been said: how many have found fault with what is sound only because their understanding was poor! And say to whoever does not do my purpose justice: the excuse is a right owed to the beginner,

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and for a youth of twenty-one years an excuse is accepted and fitting, above all in the tenth century, the age of ignorance, corruption and strife. The writing of this ordered rajaz was at the beginning of Muḥarram of the year forty-one after nine hundred.

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Then blessing and peace for ever on the Messenger of God, the best who ever guided, and his family and trustworthy companions, who travel the paths of salvation, as long as the sun of the day crosses the constellations and the shining full moon rises in the dark.

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