180 - Proof Positive: The Logical Tradition

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Logicians ply their trade across a millennium of Islamic history, considering such issues as the status of logic itself and the Liar Paradox.



Further Reading

• A. Alwishah and D. Sanson, “The Early Arabic Liar: the Liar Paradox in the Islamic World from the Mid-Ninth to the Mid-Thirteenth Centuries CE,” Vivarium 47 (2009), 97-127.

• K. El-Rouayheb, Relational Syllogisms and the History of Arabic Logic, 900-1900 (Leiden: 2010).

• K. El-Rouayheb, “Post-Avicennan Logicians on the Subject Matter of Logic: Some Thirteenth- and Fourteenth-Century Discussions,” Arabic Sciences and Philosophy 22 (2012), 69-90.

• D. Perler and U. Rudolph (eds), Logik und Philosophie: Das Organon im arabischen und im lateinischen Mittelalter (Leiden: 2005).

• N. Rescher, The Development of Arabic Logic (Pittsburgh: 1964).

• T. Street, “Arabic Logic,” in D.M. Gabbay and J. Woods (eds), Handbook of the History of Logic vol.1: Greek, Indian and Arabic Logic (Amsterdam: 2004), 471-556.

• J. Walbridge, “Logic in the Islamic Intellectual Tradition: the Recent Centuries,” Islamic Studies 39 (2000), 55-75.

Stanford Encyclopedia: Arabic and Islamic Philosophy of Language and Logic 

My thanks to Riccardo Strobino for advice on this episode!


SMatthewStolte on 15 June 2014

Apple Podcasts App

I listened to this episode with my iPhone’s web browser, but I don’t seem to be able to get it to show up on my Podcasts app. Maybe there’s just a delay.

In reply to by SMatthewStolte

Dave Martin on 15 June 2014

Episode not in podcast app

I have the same issue.

In reply to by SMatthewStolte

SMatthewStolte on 16 June 2014

It is showing up now

It is showing up now (Monday).

In reply to by SMatthewStolte

Peter Adamson on 16 June 2014


Sorry, this was my fault - I didn't upload it properly. But as you say it's fixed now!

In reply to by Peter Adamson

SMatthewStolte on 16 June 2014

Thanks for the for the

Thanks for the for the response. Glad it was simple.

Hoom on 3 December 2016

Mulla Nasr al-Din

Is this character based on an actual person, or is it just a placeholder name people use for such jokes?

In reply to by Hoom

Peter Adamson on 4 December 2016

Nasr al-Din

Good question. I don't know actually but I assumed the latter.

Madrasa drop out on 17 September 2017

We still study logic in Madrasa!

As late as the 20th century? Bihari's Sulum Al-Ulum and dozens of commentaries on it are still required reading in many of the better off subcontinental madrasas. In some cases commentaries on the Sulum account for the bulk of the subject, alongside Al-Abhari's classic commentary on Ibn Al-Muqaffa's translation of the Isagoge. It might be rare, but a distant relative of mine did study Avicenna's Al-Shifa during her time in madrasa which is very unusual. The extent to which new works on logic are produced appears miniscule, for various reasons, but I think it's wrong to imply that it's a dead tradition. Avicenna, Mullah Sadra, Muhibb Allah Bihari, Hussein Maibazi, Mullah Jaunpuri and Mir Muhammad Zahid are still studied in many places and not as mere historical figures. 

In reply to by Madrasa drop out

Peter Adamson on 18 September 2017

Madrasa curriculum

Yes, thanks for pointing this out! I think I allude to this a bit more in later episodes; and anyway I didn't mean to imply it is a dead tradition, it also lives on in the schools of Iran. I'm fascinated to hear about your relative studying Avicenna directly!

Alexander Johnson on 22 March 2019

Liar's Paradox

I first encountered the Liar's Paradox in "Sideways Arthimatic from Wayside School."  There it is "1. the answer to question 2 is false" "2. the answer to question 1 is true".  the 'solution' i came up with in elementary school was focused on breaking the infinite chain.  so i said if 1 is true, 2 is false, but if 2 is false, then 1 can't be true, so 1 is false.  however, just because 1 is false, doesn't mean 2 is true, it just means that 2 is a different kind of false than 1 is refering to.  therefore both of them are false.  i guess it was based on the idea that there is only one way to be right but many to be wrong.  i don't really fully remember the reasoning, but the answer stuck with me all these years.

if i wanted to follow young me's ideas and explore them, being my own historian, i might argue:  

"if 1 is true, then 2 must be false.  but then if 2 is false, one just has to be not true.  If 1 is not true, that doesn't mean it is false (just like not white doesn't mean black), therefore, 2 is false, and 1 is just not true.  therefore, the problem is the idea that a statement is only true or false."

i don't think i'm hitting on any real solution, just thought i'd share, however.

In reply to by Alexander Johnson

Peter Adamson on 24 March 2019

Liar's paradox

Yes, that is a possible solution: just introduce a third status or truth value like neither true nor false. But most logicians, historically, were committed to the Aristotelian principle that there is no such third truth value so this was not an available way out.

David Marans on 19 November 2021

Resource Correction

My previous comment suggests the Open Access LOGIC GALLERY.

Its address has changed to     http://humbox.ac.uk/5497/

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