Peter Adamson, Philosophy in the Islamic World: A History of Philosophy Without Any Gaps, Volume 3 (Oxford University Press, 2016).

Jadaliyya (J): What made you write this book?

Peter Adamson (PA): The book is actually the third volume of a book series called the “History of Philosophy Without Any Gaps,” which is based on a podcast of the same name that I have been running since 2010. The books are basically a revised version of the scripts I wrote for the podcast, with some added chapters plus supplementary material like footnotes, bibliography, maps, and so on. The idea of the project as a whole is, as the name says, to cover the history of philosophy without skipping anything. This means, for one thing, covering periods of philosophy that are pretty familiar but with attention paid to supposedly “minor” as well as “major” thinkers. For instance, in ancient Greek philosophy there were numerous episodes on big hitters like Plato and Aristotle, but also episodes on lesser known movements and figures like, say, the Cyrenaics and Maximus Confessor. One result is that I pay more attention to female philosophers than is often done, since women thinkers usually fall into the supposedly “minor” category. And then for another thing, the series covers non-Western philosophy extensively: the fifth volume, which is just about to come out, looks at classical Indian philosophy (with co-author Jonardon Ganeri), and the podcast is nowadays covering Africana philosophy. 

Both aspects of the project are relevant for this volume on the Islamic world. Obviously, having a whole book on this topic in a general history of philosophy is unusual. But also, the book covers not just major, more or less famous thinkers like Avicenna and Averroes, but literally hundreds of philosophers, with dozens getting close attention. So, while it probably is not really possible to write a book on this topic literally “without any gaps,” it is as far as I know the most detailed survey that is aimed at a general reader.

J: What particular topics, issues, and literatures does the book address?

PA: To some extent, the book covers the topics and figures you might expect, namely philosophers from al-Kindī to Averroes who were Muslims and wrote in Arabic, engaging with the classical Greek tradition. These are the figures who usually make it into histories of philosophy and occasionally onto university teaching syllabi. But I also include coverage of non-Muslim philosophers who lived in the Islamic world, which is especially important in the second part of the book. That part looks at philosophy in medieval Andalusia and quite a few Jewish thinkers are covered there. The contribution of Christian literature in Arabic is also highlighted. Chronologically, I go a lot further than most surveys of the Islamic philosophical tradition do. Usually that tradition is considered to be part of “medieval” philosophy and to end in around 1200 CE. Instead, I take the story all the way to the twentieth century, with about one-third of the book being dedicated to “post-classical” topics. Finally, I should add that I was looking here at figures who are obviously “philosophers,” such as commentators on Aristotle. I try to cover everything—or at least, as much as possible—that should interest a historian of philosophy. So, there are chapters on the sciences, for instance on optics, and on theology and mysticism, showing how these intellectual traditions interacted with those that are more usually called “philosophical.” 

J: How does this book connect to and/or depart from your previous work?

PA: My main area of research is late ancient philosophy and philosophy in the Islamic world, so to some extent I was on familiar terrain writing this book. In particular, I have written quite a lot on figures like al-Kindī and Avicenna. But I had not worked much on the post-classical tradition or on Jewish philosophy, so that was new for me. Conversely, working on this project has also changed my research agenda quite a bit. In particular, discovering just how rich the post-classical period is convinced me that I should be trying to do more to bring it to wider awareness. So now I am running a funded research project in Munich on the “Heirs of Avicenna,” where we are producing thematically organized volumes on philosophy in the twelfth and thirteenth century in the Islamic East. My hope is that, with other projects like this, the word will get out that philosophy did not just expire in the Islamic world around the time that it recovered in Christian Europe. 

J: Who do you hope will read this book, and what sort of impact would you like it to have? 

PA: It is designed to be readable without any background knowledge. Probably the ideal thing would be to have read the other volumes in the series, especially those on either side of it. Volume 2 was on later ancient philosophy, which leads directly into the Islamic world because philosophy there was strongly influenced by intellectual currents from late antiquity. Volume 4 is on Latin medieval philosophy and charts, among other things, the influence of texts from the Islamic world on medieval philosophy. Still, the idea is that each volume can be easily followed on its own. Despite all the historical detail, the writing style is quite “light”—for example, there are running gags and jokes, aiming for the effect of an informative but also entertaining classroom experience. Obviously, my hope is not that everyone who reads the book, or listens to the podcast, goes off to be an expert researcher on Islamic philosophy. It would be great if it inspired some people to read further, pick up primary texts in translation, or dip into other secondary literature. To this end, I gave rather extensive “further reading” suggestions at the end. For this reason, the book would hopefully also be useful as a text to accompany a course on the subject (in fact, I use it this way). But, really, it is supposed to reach beyond academia and just get people to re-think the nature of philosophy in the Islamic world. As I have already implied, there are a lot of myths about this subject out there and anyone who looks through this book even casually will quickly see that the myths are wrong.

J: What other projects are you working on now?

PA: I have a book that will be coming out with the same publisher, Oxford University Press, later this year, on an early thinker of the Islamic world named Abū Bakr al-Rāzī. He was a Persian doctor who developed an unusual and, in the eyes of some, heretical theory about how the cosmos is formed. In the book I talk about that theory, as well as the philosophical aspects of his medical writings and also his treatises on ethics. 

Within the “without any gaps” project I am working on Africana Philosophy, as I mentioned, together with co-author Chike Jeffers. At the same time, I am putting out a series on the Italian Renaissance. Aside from all that I am currently running two research projects in Munich, the one I mentioned before about the reception of Avicenna’s philosophy, which is sponsored by the German Research Council; and then, financed by the European Research Council, a project on animals in the Islamic world. The latter is a really interesting topic because it turns out that philosophers and theologians in this tradition had innovative and surprisingly “generous” views on both animal minds and the moral question of how we should treat animals. This is particularly worth exploring, I think, because it is so commonly assumed that philosophers did not start to think about the animal world in this way until very recently.

J: What is your favorite passage in the book?

PA: This would be:  

The Iberian Peninsula was mostly under the rule of Muslims for several centuries. They arrived in a year that will be easy to remember for American convenience store patrons: 711. I can’t resist telling a legend about this conquest. It’s said that the kings of the Christian Visigoths had a tower sealed with many locks. When each king came to power, he would add another lock, until there were twenty-seven of them keeping safe the secret inside. Finally, a king could not restrain his curiosity and had the locks opened to see what was inside the tower. Inside he found paintings of Arab warriors on horseback, and a scroll that said: ‘When this chamber is violated… the people painted on these walls will invade Spain, overthrow its kings, and subdue the entire land.’ Thus did curiosity kill the Catalans.”

Excerpt from the book 

From the chapter “Avicenna on Existence”

I can’t believe I haven’t yet mentioned my sister. She’s a few years younger than me, and also used to study philosophy. But she wanted a more exciting life, and ran off to join the circus. Before long she became a skilled trapeze artist, and married the bearded lady (after some initial confusion, the marriage was annulled). Her restless spirit led her to quit the circus though, and she moved into my basement, where she spends most of her time writing these books about the history of philosophy, which I pass off as my own. Oh, one other thing you should know about my sister: she doesn’t exist. I have never had a sister and, barring some very surprising news, am never going to have one. Yet it seems pretty clear that this sister of mine could exist. Everything I told you about her would be, if not likely, at least possible – well, apart from the idea that anything could be more exciting than philosophy. 

It isn’t just my trapeze-artist, basement dwelling sister who doesn’t exist but could have. There are an infinity of things that will never exist, even though they apparently could quite easily exist. They needn’t be people – unicorns and centaurs, the fourth of the five moons that are orbiting around the earth, a mountain made entirely of gold – it seems obvious that such things could have existed, yet they never will. Then on the other hand, there are the things that do get to exist, but might just as easily not have existed. You and I, and every human who has ever lived or ever will, would fall into this category. In fact, if you look around you, you won’t see anything that absolutely had to exist. Rather, the world is full of what philosophers would call contingent things. To call something contingent is just to say that it is neither necessary nor impossible. An impossible thing would be, for instance, a round square, or an activity even more worthwhile than philosophy.  

Philosophers refer to necessity, contigency and impossibility as “modal” concepts, and to the whole phenomenon as “modality,” because these are three “modes” that can apply to things or to statements. You might find it strange to think about existing things in this context, and quite a few modern-day philosophers would agree. For them, it would be statements or propositions that are characterized by necessity, contingency, or impossibility. You can best think about this in terms of truth. A necessary proposition is one that is guaranteed to be true, an impossible proposition one that must be false, a contingent proposition one that might be true or false: “I have a sister who was a trapeze artist” is false, but could have been true. We already find this in Aristotle, minus the examples about trapeze artists. He talks quite a bit about modality in his logical works, as when he tells us that if the two premises of a syllogism are necessarily true, then the conclusion that follows from them will also be necessarily true. Modality also turns up in his epistemology, when he says that knowledge in the strict sense must involve necessary truths.

This was an aspect of Aristotle’s logic that particularly interested Avicenna. His own extensive writings on logic respond to Aristotle and to his commentators, up to and including al-Fārābī. But as usual, Avicenna’s respect for and use of his predecessors from Aristotle onwards, didn’t prevent him from putting forth innovative ideas of his own. Logic was certainly no exception. This was also one area where Avicenna was especially successful in supplanting Aristotle. Theologians and others trained in the later madrasa educational system were brought up on a diet of Avicennan logic, much as the philosophy students of late antiquity had begun with the Aristotelian Organon. Some of Avicenna’s influential ideas in logic have to do precisely with modality, and constitute an advance on what we find in Aristotle. On the one hand, Aristotle strenuously insists that there are some things that could be the case but aren’t. He scornfully refutes a group of philosophers called the Megarians, who believed that there is no such thing as unrealized possibility. As Aristotle points out, this would eliminate the difference between being blind and just not seeing anything at the moment. In fact, it’s perfectly possible to be able to see, without actually seeing, like when one’s eyes are closed. On the other hand, Aristotle says in other contexts that what is eternally the case is also necessarily the case. He believes that if the heavens exist eternally, then it follows that they exist necessarily. That may be a seductive thought, but notice the apparent implication: if it is eternally the case that something doesn’t exist, then it necessarily doesn’t exist. In other words, my sister, who never has existed and never will, turns out on this theory to be impossible.

That way of thinking of things seems unfortunate from our point of view. But generations of logicians and metaphysicians in antiquity and the early medieval period were happy to follow Aristotle on this score. It is sometimes called the “statistical” or “frequentist” view of modality. According to this statistical view, to say that something is impossible is nothing more nor less than saying that it never occurs, and to call something necessary is just to say it always occurs. Rather uncomfortably, this leaves us with only one remaining option regarding the contingent things in the middle: we’ll have to say that they sometimes occur, but not always. For instance, to say it is contingently true that a human sleeps would be to say that sometimes humans sleep and sometimes they don’t. That sounds fine when you apply it to general types of things like humans. Probably if no humans anywhere ever went to sleep, we would indeed be tempted to conclude that it is impossible for humans to sleep. But if you apply it to individual things that don’t occur, it looks much less plausible. As I say, it doesn’t seem to follow from the fact that my sister never exists that she couldn’t possibly exist. 

In Avicenna’s logical system, it remains the case that propositions have statistical implications, even if they may seem not to. In fact, he criticizes philosophers like the members of the Baghdad school for overlooking this point. If I say “the giraffe is tall,” Avicenna would take this to imply that the giraffe is tall at some time or other. However, he also ties modality to the natures, or essences, of things. If I say that it is possible for humans to be trapeze artists, that will mean that it is compatible with human nature to be a trapeze artist. This will apply to every human, including humans like me who wouldn’t even consider attempting to become a trapeze artist. Thus we can now apparently say that there are some things that could be the case, but never are. 

So far, I’ve been talking about this as if it were solely an issue of logic. But it is also an issue about what exists – an issue of metaphysics. For, just as it is compatible with my nature for me to be a trapeze artist or not, it is also compatible with my nature to exist or not. Here, we have arrived at what may be Avicenna’s most famous philosophical distinction, the distinction between essence and existence. He makes the point with the example of a triangle. If you just consider the nature or essence of a triangle, and if you were paying attention in geometry class as a kid, you’ll be able to see that a number of things follow from that essence: it must have an odd number of sides, and it must not be round. If you were paying more attention than I was, you might even be able to deduce that its internal angles are equal to the sum of two right angles. But one thing the essence of triangle will not tell you is whether it exists or doesn’t exist.  

So here is something I share with triangles (albeit not the only thing; they don’t have sisters either): both the triangle and I are contingent existents. This simply means that we have essences that are compatible with both existence and non-existence. In this we are unlike, say, round squares or carnivorous giraffes. These things cannot exist, because their essences preclude their existence, which is just to say that they are impossible. That’s pretty obvious with the round square, since its being round will prevent it from being square, and vice-versa. We might express the point by saying that the existence of such a thing would yield a contradiction. You might object to my other example though, on the basis that you’re perfectly able to imagine a meat-eating giraffe, so this can’t be an impossible existent. But I think Avicenna would disagree. As any good Aristotelian knows, it is essential to giraffes that they be vegetarian. The test for metaphysical possibility is not sheer conceivability, but what is compatible with the essence of a thing. Hence, not only are round squares impossible, but also non-rational humans and carnivorous giraffes.