On selections and commentary about Avicenna's argument from around 1020 C.E. for the existence of God (including arguments to prove that God has the person-like properties that Islam imputes to him) and his "flying man" argument for the soul's essential independence from matter. Featuring Mark, Dylan, and our guest Peter Adamson from the History of Philosophy podcast.
Avicenna (aka Ibn Sina) historically provided an essential link between Aristotle and Thomas Aquinas, and his influence not only shows up in European "modern" philosophy about God (like Descartes), but is even stronger in the Middle East. He wrote his own version of the Aristotelian corpus that had been passed down to him, first in The Book of Healing (aka Shifa or The Cure), then more briefly in The Book of Deliverance (Najat or The Salvation), and then with extreme conciseness in Pointers and Reminders (Isharat or Remarks and Admonitions). Our sources pulled from all three of these readings and more.
The argument for the existence of God is one of those considered later by Aquinas as "the argument from contingency," and asks the question "why is there something rather than nothing?" We have a strong intuition, says this argument, that anything we experience must have a reason for its existence, must have something that it relies on for its existence. In other words, everything we experience is contingent. The issue is not (as with the cosmological argument) causality over time: We're not asking what temporally prior thing caused the thing we're contemplating, but what right now accounts for the thing. So yes a house in a familiar sense was caused by its builder, but more immediately, its cause is the materials that make it up, arranged in the way they are. And what causes in this sense a piece of wood making up the house to provide the support it does? Its makeup: molecules in a particular type of configuration. And so the chain goes on. If each of the links of this chain is contingent, relying as it does on something else (in other words, if that cause hadn't occurred, neither would the contingent thing; its existence is contingent on the existence of its cause), could it be that the whole chain is contingent? Could it too have an underlying supportive cause? Avicenna says no: Then that cause would just be part of the whole chain of contingency. The whole chain needs to have some stopping point, or else none of it would exist, and that's the necessary being.
So even though we've never experienced anything like this necessary being, reason itself tells us that such a being must exist, based on our experience of contingency in the world. One of our sources (a 2001 article by Toby Mayer) says that the argument combines this initial experiential component (like the cosmological argument) with a definitional, a priori element (like the ontological argument). It's a sound argument so long as you accept that initial metaphysical intuition that everything we experience is contingent.
Even if this argument works to establish the existence of a necessary being, why would we think that this is God? Avicenna uses the two properties he's proven (i.e. that it's necessary, and that it causes all the other beings) to derive God's other properties. With this picture of instantaneous causality that we've described, God ends up being the immediate cause of everything else: this is his omnipotence. This picture is unlike Plato's Timaeus where there was some non-God substance (the chora or receptacle) that is the raw material that God uses to build the world. Instead, the world emanates directly from God's nature.
A comparison and contrast with Leibniz may be useful here: Leibniz's Theodicy gives us a picture of a God who scans all possible worlds and is compelled by the necessity of His good nature to create the optimal one. So in a sense, God makes a choice, but because He couldn't have made any other choice, this is really no choice at all. For Avicenna, God likewise makes the best possible world for us, but the process does not require scanning other possibilities. In fact, Avicenna's metaphysics entails that everything that is possible actually does happen. Why? Because possible is just another word for contingent. Considered in itself, the computer in front of me might or might not have been there. Its existence is contingent on many circumstances and compositional factors. But if we then keep going back down the causal chain, we get to the necessary being, whose existence is sufficient to necessitate all the other links in the chain. So really, despite appearances, everything we perceive is really necessary. Again, it's merely contingent when considered in isolation, but since the whole mechanism is necessary, everything that actually happens (that exists) is necessary, and there were no other possible ways that the world could have been. That's merely a human illusion.
God as the underlying ground of everything must, then, exist outside of time. He's not like a deist might say someone who was the first cause temporally, hitting the first domino, and then the world rolled into being, with maybe us conscious beings having free will, able to do things that God didn't ultimately determine or know about. Even Leibniz (not a deist) thought that God creates the plan but then the rest runs like a perfect machine, with part of that machine being us with our free will. God determined that free will would be best for us, and so caused us to have that, but then doesn't cause our choices. For Avicenna, the relation between God and His creation is much more immediate. This "emanation" means that we're all in effect part of God, and His omniscience is explained as His knowledge of Himself. This knowledge is of course not like most human knowledge, where at some point we come to learn a fact, because Avicenna's God never changes and so can't come to learn anything, or else before that learning He would have been ignorant of that knowledge. Instead God knows everything abstractly, like the innate knowledge we have according to Plato of the Forms. Essentially, God can reason out everything that has or will happen. Even this doesn't quite capture it, because "reasoning out" sounds like a sequential process, but God's knowledge just like God's causality is immediate, or rather atemporal.
Just to give one more example, what would prove God's generosity? This sounds like a human quality that a metaphysical posit like the necessary ground of the universe could not have. But Avicenna said that generosity is defined as giving (well, emanation) without need, and God by definition doesn't have any needs, and so isn't benefited by creating the world for us. So you keep words like "know," "give," and "love," but you redefine them so they can apply to this very non-human entity. The Scriptures... well, of course they're filled with anthropomorphism, because that's what you need to reach non-philosophical readers, but philosopher who have followed Avicenna's reasoning will know how to read them correctly to get at the literal, hard-to-grasp truths beneath the human-oriented stories.
The second topic was considered is our knowledge of the soul. Avicenna's famed "flying man" experiment asks us to imagine being a person who has just been created with all mental faculties intact, but no memory (because the person has just that moment been created, full mature), and with no sensation. You're "flying" because your limbs are splayed and you can't feel the earth under you. The word is not quite apt, because you also can't feel air pressure, or gravity, or your own sense of balance. There's no sensation at all, is the point. Yet even then, Avicenna claims that you'd know that you exist.
This is supposed to prove not just a la Descartes that "I think, therefore I am" but that what you are essentially, as a soul, is something non-material. Avicenna read Aristotle's definition of the soul that it's the "perfection" or "form" of the body--in other words something the body does, the state that it's in--and was unsatisfied. This is a characteristic of the soul, i.e. we encounter it in our bodies, but doesn't say what the soul actually is in itself, doesn't capture what makes the soul a soul.
According to Avicenna's epistemology, when we grasp some concept, we necessary grasp its constitutive attributes, i.e. we understand what makes it as it is. Otherwise, we haven't grasped it at all. I might see a passing cow, but if I don't understand what an animal is, then I haven't really seen the cow; I've just seen a shape. Now, I might not explicitly think when I see the cow that it's an animal, and I certainly don't think explicitly about what an animal is such that it's different than a plant or inanimate matter. But all of these logical entailments are right there, implicit in my thought, according to Avicenna.
The flying man argument is supposed to call to mind a self-awareness that we always have, even if we've never explicitly considered it or not. Whenever I have any perception at all, or think any thought, I'm also implicitly aware that it's me having that perception or thought. The explicit content of my thinking of of perceiving my computer is the computer, but one of the implicit contents (along with things about the computer) is this element "me." While someone like Heidegger or Merleau-Ponty would claim that really, the "me" in that experience is always an embodied me, as in I am this body physically related to the computer in front of me, and my merely thinking of (remembering) a computer after the fact is an experienced derived from that perception, the epistemic situation according to Avicenna when it comes to knowing yourself is actually more like God's knowledge of Himself: We have this direct knowledge of self (through BEING the self) that is actually a prerequisite to our having any of these other experiences. So I don't learn about the self through having an experience of perception, but instead my prior knowledge of self is required as an ingredient for perception to be possible. I can only perceive myself as being in a body because I already have a prior understanding of myself, and I know from that prior understanding that this self does not include residing in a body as an essential component. I could (in the flying man thought experiment) have a conception of self without having had a conception of body. There's no reason to think that this conception of self was fallacious, that in the flying man situation I really wouldn't be grasping the self at all, so therefore I grasped everything essential about self-hood even in that weird, imagined situation. Therefore it's not essential that a soul be in a body, at least conceptually. In other words, it's possible for a soul to not be in a body.
...And if you'll recall my argument that everything that's possible is in fact actual, then you can see how Avicenna uses this to show that the soul not only can but does live on without a body. The soul is experienced as contingent (possible), but in moving to its necessary ground, we don't have to say "the soul wouldn't be there unless the body was." I know as flying man that there is a soul that is me, and that it must be contingent on something, and so I can follow that chain to God, but no other links in that chain are apparent: It seems like I was directly caused by God.
You can probably see why I don't agree with this argument. I don't agree with Avicenna's epistemic claim that to be able to grapple with some idea, particularly one we're experiencing, we have to understand its nature. So to me, it's perfectly plausible that the nature of the self may in fact necessarily involves its biological base, and also perfectly plausible that we might not know that even though we can think sensibly about selves. This is the common objection to Avicenna: That it violates the sense-reference distinction, as discussed in our Frege episode. For example, I can be looking at Clark Kent and not know that Clark Kent is Superman. I am in fact looking at Superman, but I don't know that. There would be no justification to say "since I'm sensibly grasping this guy Clark Kent, I have grasped his essence, and can definitively say he's not Superman." In this case, that claim would not only be unjustified, but actually wrong.
The 12th century thinker that Peter praises toward the beginning is Fakhr al-Din al-Razi.
Our main text selections for the argument for the existence of God is Classical Arabic Philosophy: An Anthology of Sources, translated by J. McGinnis and D.C. Reisman. You can try this online copy. We read p. 211-219.
The source with the arguments for God's attributes is "From the Necessary Existent to God," written by Peter in the collection he edited: Interpreting Avicenna: Critical Essays (2013).
You can read the collection of excerpts called "On the Soul: The Floating Man" online. Our main commentary on that was "The Thought Experimental Method: Avicenna’s Flying Man Argument" (2020) by Peter Adamson and Fedor Benevich.
Other secondary sources we looked at (which typically included textual references not included in the main readings) were:
- "Avicenna on Self-Awareness and Knowing that One Knows" (2008) by Deborah L. Black
- "Ibn Sina’s 'Burhan Al-Siddiqin'" (2001) by Toby Mayer
- "Avicenna’s Proof from Contingency for God’s Existence in the Metaphysics of the Shifa" (1980) by M.E. Mamura
And of course, a good way into all of this is to listen to Peter's History of Philosophy episodes covering Avicenna and related thinkers. The Avicenna ones in particular are eps. 138-142.
Image by Solomon Grundy. Audio editing by Tyler Hislop.
Continues on part two.