251. Masters of the University: "Latin Averroism"

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Did Siger of Brabant and Boethius of Dacia, who have been called “Latin Averroists” and “radical Aristotelians,” really embrace a doctrine of “double truth”?



Further Reading

• J.F. Wippel (trans.), Boethius of Dacia: On the Supreme Good, On the Eternity of the World, On Dreams (Toronto: 1987).

• R. McInerny (trans.), Aquinas Against the Averroists on There Being Only One Intellect (West Lafayette: 1993).


• B.C. Bazán, “Was There Ever a ‘First Averroism’?” in J.A. Aertsen and A. Speer (eds), Miscellanea Mediaevalia, vol.27: Geistesleben im 13. Jahrhundert (Berlin: 2000), 31-53.

• R.C. Dales, “The Origin of the Doctrine of the Double Truth,” Viator 15 (1984), 169-79.

• G. Klima, “Ancilla theologiae vs domina philosophorum: Thomas Aquinas, Latin Averroism and the Autonomy of Philosophy,” in Was ist Philosophie im Mittelalter? (Berlin: 1998), 393-402.

• D. Niewöhner and L. Sturlese, Averroismus im Mittelalter und in der Renaissance (Zürich: 1994).

• F.-X. Putallaz and R. Imbach, Profession: philosophe. Siger de Brabant (Paris: 1997).

• F. van Steenberghen, Thomas Aquinas and Radical Aristotelianism (Washington DC: 1970).

• F. van Steenberghen, Maître Siger de Brabant (Louvain: 1977).


Chris Valentine on 10 April 2016

How is a physicist

How is a physicist researching the Big Bang and worshiping a divine creator contradictory? Particularly when it is considered that the Big Bang theory was developed by a Catholic Priest, and was rejected by many for implying a Creator.

In reply to by Chris Valentine

Peter Adamson on 10 April 2016

Big bang

I was looking for a modern analogue of the situation faced by Siger and Boethius, where you have two alternative explanations or accounts for the same thing, one scientific and one religious. And my point was that the scientific and religious accounts are not actually incompatible, insofar as you can argue that they are explanations operating at two different levels or orders, or that one explanation appeals to resources unavailable to the other. So this is why later in the episode I come back to the example and say, "Consider the Big Bang cosmologist who goes to church on Sundays. She might say that she isn’t really being inconsistent, but just taking two different points of view on the question of where the universe came from. During the week she pursues an answer using the tools of science, and on the weekend she accepts a wholly different explanation on the basis of faith."

So actually I think the position I'm suggesting on the Averroists' behalf is very close to yours, except that you may not be willing to admit that there is even a prima facie tension between physics and religion in this case. Actually my example will still work to some extent even without the prima facie tension, since what I want to illustrate is not just the initial conflict, but the appeal to two explanations of different types.

In reply to by Peter Adamson

Bear on 18 April 2016

Big Bang

I was going to raise the point that M. le Abbé Georges Lemaître first proposed the Big Bang Theory in 1927. It was initially rejected because (a) it looked too much like the intervention of a creator, and (b) it violated the Law of Conservation of Matter: the latter implies the eternity of the universe. Since then, a particular sort of Physicist has been trying to get around this apparent Theism by making all sorts of absurd proposals, such as the "Multiverse", or the spontaneous creation of parallel and detectable universes (so much for empiricism).

A more germaine example would be to consider a Geologist who works as an academic Geologist during the week, but promotes Creationism outside his job. One account having the Earth formed many millions of years ago, the other having the Earth created 6000 years ago. I am sure such a person does exist today.

In reply to by Bear

Peter Adamson on 18 April 2016


Right, that's a nice example - I wish I'd thought of that. That does almost as well as a parallel to the eternity of the world debate, too, which is the topic of the next episode.

In reply to by Chris Valentine

Zarl on 2 May 2019

The Big Bang and Christianity

I was going to say just that! It's quite an ironic example given that the Big Bang theory is pure Christian cosmogony. As we've seen in this series, the question of the eternity vs creation of the universe was a long-standing one, but with the Big Bang theory science ended up siding with Christianity against Aristotelian eternity, which had hitherto been the position of most atheists.

Now, is this evidence that Christianity contains some deep truth? Or, as Spengler would say, are we as Westerners merely projecting our deep-rooted religious and philosophical world view onto every intellectual endeavour including physics and thus constructing models that have no universal truth but that instead correspond to the soul of our particular civilisation?

I suppose there's also a small chance that it could just be a coincidence.

Berel Dov Lerner on 10 April 2016

Siger and C.J.

All through the podcast I was thinking: C.J. was the White House Press Secretary on West Wing - was that some kind of philosophical inside joke about political spin-masters and "double truth"?

Sati on 21 April 2016

Double truth

I have a double truth to confess... I love HOPWAG but hate Reese's Peanut Butter Cups. Only kidding, everyone knows double truth is impossible, I love them both. Thanks for the episodes Peter, this episode marks where I have finally caught up. Sati.

In reply to by Sati

Peter Adamson on 21 April 2016


If anything teaches us that two apparently contrasting things can exist in harmony, it's Reese's Peanut Butter Cups. Thanks, and thanks for sticking with the series! Hope you won't be annoyed your have to wait for the new episodes from here on out...

Roman Prychidko on 21 April 2016

web site poetical philosophy

Hi Peter

I am working on launching a poetical philosophical website based on your podcast. I do not have yur e-mail to discuss.


In reply to by Roman Prychidko

Peter Adamson on 21 April 2016

My email

If you just google me ("LMU Adamson" should do it) you'll get to my email.

John Farrell on 19 August 2021

Aquinas and Averroës

Dear Prof. Adamson,

I have greatly enjoyed your books on the history of philosophy, as well as listening to several of your podcasts on Islamic and medieval philosophy.

I wanted to reach out for your view on Aquinas and Averroës. Specifically, in regards to Aquinas's On the Unicity of the Intellect. Did Aquinas read too much of his own position into Aristotle's own view's from De Anima, when he accused Averroës of --not just misreading Aristotle, but actually 'perverting' him? Wasn't Averroës being truer by also considering Aristotle's metaphysics on the question of monopsychism? Anyway, I'm curious as to whether there is agreement or consensus about how Aquinas read Averroës himself? I can't help feeling that, standing between Bonaventure on one side, and Siger and the 'Averroists' on the other, and wanting to adopt as much of Aristotle's work as possible given the threat of condemnations, he sort of 'threw Averroës under the bus' (to use an anachronistic expression). Does that make sense?

~John F

In reply to by John Farrell

Peter Adamson on 19 August 2021

Aquinas vs Averroes

Behind your question is obviously the difficult matter of what Aristotle really meant in the section on De Anima where he talks about intellect. Personally, I very much doubt that Aristotle ever entertained the notion that the human intellect is only numerically one - to the contrary I think he assumed that the intellect is a power of the embodied human soul which would die along with the body. So my reading would be more or less diametrically opposed to Averroes'. But that's just my opinion of course and people disagree fervently about how to read Aristotle - however I don't really know of any modern-day scholar who adopts an Averroist reading.

I do think you're right though that Aquinas threw Averroes under the bus: he was trying to distance himself from the radical Aristotelians, because he was a pretty radical Aristotelian himself so wanted to create distance to make himself seem more mainstream or orthodox. But that is not to deny that the reading of Aristotle he presents is sincerely held, and I guess that it is somewhat closer to how modern-day scholars read Aristotle, though the majority would probably now reject the idea that the intellect outlives the body.

Zachary on 27 August 2021

The Problems of the "Latin Averroists"

You stated right at the beginning that the Latin Averroists definitely didn't believe in the Doctrine of Double Truth, but judging from the sketch you've drawn from them in this episode you couldn't blame anyone for thinking they hold it. Siger seems to be a very different case from Boethius. Siger seems to be the more cautious one, at least as you portray them. Siger, publicly at least, denied the eternity of the world and univocity of the intellect, but thinks they are proved philosophically. His position doesn't look too different from Aquinas' position on the surface, but unlike Aquinas' position, Siger's position looks like its shows that philosophy can "prove" something that is known to be false, which would damage the idea that philosophy can bring us to the truth. Alternatively, you could resort to a Straussian reading and think that Siger wasn't serious when he said this. At least, however, you can't say that he taught a doctrine of double truth.

Boethius, however, seems to me a very different case, and it looks like he actually did teach the doctrine of double truth. Unlike Siger, Boethius is not willing to say that philosophy can prove something that is false. Instead, he wishes to say that philosophy and theology are separated into two distinct fields, and both their conclusions can be believed to be true in their own field. However, this kind of strict division looks irrational. Though their methods are very different, philosophy and theology are both talking about the same reality, so it doesn't look possible to have them hold incompatible conclusions and both of them to be true. This division does make science possible, but it looks like a very unsatisfying philosophical position.

In reply to by Zachary

Peter Adamson on 27 August 2021

Double truth

I think the important point is that in different ways, they are trying to make space for teaching of philosophy independently from theology: Siger by saying he is basically a scholar who is just trying to explain what Aristotle said; Boethius with that autonomous science move. I can see why you find that unsatisfying but I think it does make sense: his point would be that if you are doing physics (the study of nature) you cannot and should not factor in the possibility of supernatural events. If miracles are possible, as Christian doctrine insists, you have to either say "ok let's forget science entirely" or "ok let's do science but ignore the cases where miracles happen" and it makes sense that these arts masters would want to do the latter. 

The irony I see here is that in a way Aquinas was more of a rationalist than the so-called Averroists, because he wanted to insist that philosophy and theology fit together perfectly, even if theology introduces new truths that philosophy could not have established. Whereas the Averroists are basically fideists, that is, when we are in the domain of religious belief by faith, then all kinds of things can and should be believed that would otherwise be deemed false. (But that doesn't mean that they are both truth and false, just that the perspective of human reason is limited.)

In reply to by Peter Adamson

Zachary on 28 August 2021


Thank you for the response. If they are doing the type of fideism you describe that would indeed make more sense.

Fr. John Ricke… on 3 April 2023

Two comments: Gilson, Vat I

Thanks yet again for another excellent podcast.  I'd certainly be interested in your thoughts on Gilson's The Spirit of Medieval Philosophy.

I find it remarkable that the Catholic Church has made official pronouncements concerning Faith and Reason: Vatican I, Sess. 3, ch. 4.  

Best wishes.



In reply to by Fr. John Ricke…

Peter Adamson on 3 April 2023


Well, I have read the Gilson but I was in grad school which is now (checks watch) more than twenty years ago. So my memories are mighty vague. In general, what I would say about Gilson is that he was an immense scholar, on whose shoulders a lot of later work was built. I myself am not in the Thomist tradition, and I think Gilson and other Thomists have often kind of skipped too much of what happened between Aristotle and Aquinas, as if Aquinas is in direct conversation with Aristotle (I mean, he is, but there are thirty other voices in there too, many from the Islamic world). But even that may be unfair, since as I say it has been a while; in fact if I remember right Gilson is pretty good on the relevance of Avicenna to Aquinas. But as you know from the podcasts I also slightly diverge from the Aquinas-centric approach to medieval philosophy anyway.

In reply to by Peter Adamson

Fr. John Ricke… on 4 April 2023


Thank you.  It's been some time since I've read any Gilson myself.  Your comments certainly fit well with the impressions that do remain in my mind.   As always, best wishes.

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