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Contradiction التَّنَاقُض

Assents · Propositions · 9 of 10

Contradiction

al-tanāquḍ

التَّنَاقُض

(tanāquḍ) is when two differ in and such that, by themselves, one must be true and the other false.

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In a picture

Contradictories sit on the diagonals: they differ in quantity and in quality, so exactly one of them is true.

Explanation

For they must also differ in quantity: the of a is a , and of a a .

Also written as: tanaqud, tanaqudh, contradictory propositions.

In the text

وَالتَّنَاقُضُ هُوَ: اخْتِلَافُ قَضِيَّتَيْنِ بِالإِيجَابِ وَالسَّلْبِ، بِحَيْثُ يَقْتَضِي لِذَاتِهِ أَنْ تَكُونَ إِحْدَاهُمَا صَادِقَةً وَالأُخْرَى كَاذِبَةً، كَقَوْلِنَا: زَيْدٌ كَاتِبٌ، زَيْدٌ لَيْسَ بِكَاتِبٍ.Contradiction is the difference of two propositions in affirmation and negation such that, of itself, it requires one to be true and the other false, as in “Zayd is a writer” and “Zayd is not a writer.”وَلَا يَتَحَقَّقُ ذَلِكَ إِلَّا بَعْدَ اتِّفَاقِهِمَا فِي الْمَوْضُوعِ، وَالْمَحْمُولِ، وَالزَّمَانِ، وَالْمَكَانِ، وَالإِضَافَةِ، وَالْقُوَّةِ، وَالْفِعْلِ، وَالْجُزْءِ، وَالْكُلِّ، وَالشَّرْطِ.This holds only when they agree in subject, predicate, time, place, relation, potentiality, actuality, part, whole and condition.وَنَقِيضُ الْمُوجَبَةِ الْكُلِّيَّةِ إِنَّمَا هِيَ السَّالِبَةُ الْجُزْئِيَّةُ، كَقَوْلِنَا: كُلُّ إِنْسَانٍ حَيَوَانٌ، وَبَعْضُ الإِنْسَانِ لَيْسَ بِحَيَوَانٍ. وَنَقِيضُ السَّالِبَةِ الْكُلِّيَّةِ إِنَّمَا هِيَ الْمُوجَبَةُ الْجُزْئِيَّةُ، كَقَوْلِنَا: لَا شَيْءَ مِنَ الإِنْسَانِ بِحَيَوَانٍ، وَبَعْضُ الإِنْسَانِ حَيَوَانٌ.The contradictory of a universal affirmative is the particular negative, as in “Every human is an animal” and “Some human is not an animal”; and the contradictory of a universal negative is the particular affirmative, as in “No human is an animal” and “Some human is an animal.”وَالْمَحْصُورَتَانِ لَا يَتَحَقَّقُ التَّنَاقُضُ بَيْنَهُمَا إِلَّا بَعْدَ اخْتِلَافِهِمَا فِي الْكَمِّيَّةِ، لِأَنَّ الْكُلِّيَّتَيْنِ قَدْ تَكْذِبَانِ كَقَوْلِنَا: كُلُّ إِنْسَانٍ كَاتِبٌ، وَلَا شَيْءَ مِنَ الإِنْسَانِ بِكَاتِبٍ، وَالْجُزْئِيَّتَيْنِ قَدْ تَصْدُقَانِ كَقَوْلِنَا: بَعْضُ الإِنْسَانِ كَاتِبٌ، وَبَعْضُ الإِنْسَانِ لَيْسَ بِكَاتِبٍ.Between two quantified propositions there is contradiction only when they differ in quantity, because two universals can both be false, as in “Every human is a writer” and “No human is a writer”, and two particulars can both be true, as in “Some human is a writer” and “Some human is not a writer.”وَاسْتِثْنَاءُ نَقِيضِ التَّالِي يُنْتِجُ نَقِيضَ الْمُقَدَّمِ، كَقَوْلِنَا: إِنْ كَانَ هَذَا إِنْسَانًا فَهُوَ حَيَوَانٌ، لَكِنَّهُ لَيْسَ بِحَيَوَانٍ، فَلَا يَكُونُ إِنْسَانًا؛And affirming the contradictory of the consequent produces the contradictory of the antecedent, as in “If this is a human, it is an animal; but it is not an animal, so it is not a human.”

Examples

“Every human is an animal” and “Not every human is an animal”

Related terms

Practise

4 question(s) on this term, in the practice set for propositions.

Go to practice · 8 questions

Test yourself

3 questions. With 6 out of 10 or more (two stars) the next term opens.

Question 1
When are two propositions contradictory?
Question 2
What is the contradictory of “No animal is a stone”?
Question 3
Which pair is contradictory?

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