If one reads through the dialogues of Plato, it won’t take long to realize that he is never short of arguments for the immortality of the soul. It seems to be one of his favorite topics to write about, and apparently he held the point as of utmost significance. A few months ago, I wrote a paper for school on three of these arguments in his Phaedo. But he also writes about it in the Republic, Meno, a bit in Timaeus, and, the one we’ll be looking at in this post, Phaedrus. In general, as an Aristotelian rather than a Platonist, I don’t tend to accept many of Plato’s arguments for the immortality of the soul (although I find them fascinating and profound), especially considering that Plato held the soul to not only exist after death, but also to have pre-existed our physical birth. Plato is, in many ways, a radical dualist, holding the human soul to be the true self and the body to be merely a prison thereof. I strongly disagree. But for now, my reason for looking at one of these arguments is not to discuss immortality.
I regard Aquinas’s “Argument from Motion” or First Way as perhaps the strongest argument for the existence of God that there is. But it’s certainly not an argument that St. Thomas just drew out of thin air; it had a long history of development. For the most part, this history can be traced to Aristotle, since he first presents the argument as really intended to show that there exists some ultimate being or cause behind the universe. While Aristotle’s version is certainly the first fully drawn out and “technical-ized” form of the argument, I think its general sentiment can be found earlier, namely in Plato. Although, as we’ll see, Plato doesn’t really seem to have used the argument as pointing to some cause of motion behind the universe; but I think his presentation thereof still has some interesting implications.
In the dialogue of Phaedrus, Socrates is discussing with the character Phaedrus about a number of topics, especially the nature of love. At one point in the conversation, Socrates gives a speech about the souls of the gods and of men, and in one brief section gives an argument for the soul’s immortality. I’m going to quote two different versions of this argument below. The first is directly from Plato’s Phaedrus:
“The soul through all her being is immortal, for that which is ever in motion is immortal; but that which moves another and is moved by another, in ceasing to move ceases also to live. Only the self-moving, never leaving self, never ceases to move, and is the fountain and beginning of motion to all that moves besides. Now, the beginning is unbegotten, for that which is begotten has a beginning; but the beginning is begotten of nothing, for if it were begotten of something, then the begotten would not come from a beginning. But if unbegotten, it must also be indestructible; for if beginning were destroyed, there could be no beginning out of anything, nor anything out of a beginning; and all things must have a beginning. And therefore the self-moving is the beginning of motion; and this can neither be destroyed nor begotten, else the whole heavens and all creation would collapse and stand still, and never again have motion or birth. But if the self-moving is proved to be immortal, he who affirms that self-motion is the very idea and essence of the soul will not be put to confusion. For the body which is moved from without is soulless; but that which is moved from within has a soul, for such is the nature of the soul. But if this be true, must not the soul be the self-moving, and therefore of necessity unbegotten and immortal?” .
The same argument is translated/expanded in Cicero’s The Dream of Scipio, and I think Cicero’s version brings out a few points more fully:
“That which is always in motion is eternal; yet that which communicates motion to something else, but is itself moved by another force, must necessarily cease to live when the transmission of this motion to it has ceased. Consequently the only thing that never ceases to move is something which has the power of starting up motion all on its own–it can go on moving because its power to achieve motion depends on itself and itself alone. This, therefore, it must be concluded, is the source and first principle of motion for all things that move. Being the first principle, it never had a beginning: since the first principle is what everything else has originated from, it cannot possibly have originated from anything itself. For if it owed its origins to something else, it could not be described as the first principle. And since it never had a beginning it will never have an end. For if the first principle were destroyed it could never be reborn from any other source and would no longer be able to create things on its own account–which is obviously what the first principle has to do. The beginning of all movements, then, comes from that which has set itself in motion: which can neither be born nor die. For if that were not so, one would have to envisage the entire heavens and all things that have ever been created crashing down and coming to an end–for that is what would happen if the force generating their motion were taken away from them. Since, therefore, it is plain that the self-moving principle is eternal, the same must evidently apply to the human soul. For unlike lifeless objects which can only be set in motion from outside, the soul, by its very essence and nature, is a living thing such as can only derive its life and motion from within itself. And since, uniquely, it possess this characteristic of self-impulsion, surely it has no beginning, and lives for ever” .
I’d like to here explore several aspects of these arguments, not as attempts to defend them but simply because I find them interesting and relevant to other arguments which I am committed to, namely the First Way.
I mentioned above that I didn’t think Plato’s use of the argument is meant to point to some cause of motion behind the universe; and that’s true in the sense that in this passage Plato isn’t trying to argue for the existence of such a Cause, since he seems to just take it for granted. But it does appear, on closer examination, that Plato perhaps understood the argument as being able to establish the existence of that Cause, if one were to use it as such. From what I can tell, it seems almost like Plato’s using the argument as an argument by analogy. In other words, I take him as saying something like this: just as the motion of the universe points to some First Mover of the whole universe, so, by analogy, does the motion of living beings point to some “soul” as a kind of “first mover” of the living being. Which is, on its own, an extremely profound thought with echoes elsewhere in Plato’s writings. In Timaeus, for instance, Plato contends that the universe itself, as a whole, is a living thing with its own soul.
In order not to cause misunderstanding, we should make clear what is meant by “soul” in these passages. In modern times, especially since Descartes’s division of soul and body into two distinct substances, it is common to think of the soul as a purely spiritual or mental thing, equating it sometimes with our consciousness, our reasoning, our emotions, etc. For the ancient Greeks around this time, however, for the most part the soul was just considered that which makes something alive. So not just humans were believed to have souls, but animals as well, and any living organism. The human soul, of course, was believed to be unique in that, to use their own words, it was thought to be in some sense “divine”. This was normally attributed to the rational capacity of the soul, which was often distinguished from the purely appetitive and other non-rational parts.
Living things were often characterized as “self-movers”. This makes some sense. Stones and tables and other inanimate objects seem only to “move” when “moved” or acted upon. But living things move on their own, “at will” as it were. When I want to walk across a room, I don’t need a friend to move me. I just will it, and my body moves. But how is this possible? Since motion requires some cause of motion, how can living things move “uncaused”? Plato’s answer here is that the soul constitutes a “first mover”, or a “self mover”, something which we must just postulate has the ability to move itself without some prior, more fundamental mover.
Plato begins by noting that “that which is always in motion is eternal”. This might seem a little backwards, for in the argument from motion which Aquinas takes up and defends, the eternal First Mover is “immutable”, or not undergoing any motion. But, actually, Plato’s statement here is just trivially true. For whatever is always in motion is, by definition, eternal or immortal, always existing. The question is, first, is there any such thing at all? And, second, is the soul such a thing? Plato answers yes to both.
Here, Plato asserts a premise that is, in some ways, strikingly similar to premises in the later arguments from motion: “That which moves another and is moved by another, in ceasing to move ceases also to live”. Or, as Cicero puts it: “That which communicates motion to something else, but is itself moved by another force, must necessarily cease to live when the transmission of this motion to it has ceased”. On one level, this might be seen just as a type of causal principle. The idea is that there’s two kinds of motion. On one kind, what is moving is moved by another, so that the whole motion and activity depends entirely on the “another” which is doing or causing the motion. If this “another” ceases to exert his causal force, the motion itself stops. But there’s apparently another kind of motion: “Only the self-moving, never leaving self, never ceases to move, and is the fountain and beginning of motion to all that moves besides”. Or, per Cicero: “Consequently the only thing that never ceases to move is something which has the power of starting up motion all on its own–it can go on moving because its power to achieve motion depends on itself and itself alone.” Now, we might have reason to question this conclusion. After all, as Aquinas held, couldn’t it be possible for something that’s moving in the first sense to always be in/continue this motion by always being moved by its mover? In other words, we might be skeptical that something which depends on a cause for motion must necessarily have its motion only temporarily, non-eternally. But there may be a way to defend it. As we’ve already noted, the difference between Plato’s and Aquinas’s understanding of a First Mover is that the latter takes this to be something immutable while the former does not. For Plato, a First Mover doesn’t seem to have to be unmoving; rather, it is moving, but it is the cause of its own motion. So suppose there were something that is eternally being moved by something else. That something else will be “before” the thing being moved in the sense that it is causally prior, not necessarily temporally prior. Maybe Plato thinks that anything which receives its motion from another could not possibly be eternally in motion in a temporal sense; but maybe he just thinks that the thing being moved cannot be “causally eternal” in the sense that it must always be receiving its motion from something more fundamental than itself. Either way, Plato’s point is still clear. Something which relies on a cause for its motion is only “contingently” in motion, we might say; it very well could “lose” its motion, and it is not up to itself at all whether or not that happens.
He is nonetheless clear that whatever moves itself and is not moved by another is necessarily “the fountain and beginning of motion to all that moves besides”, or “the source and first principle of motion for all things that move”. This is curious, since Plato began the passage by talking specifically about the soul. But this statement seems to be referring to something much more “ultimate” than a mere soul. After all, we’d hardly say that some individual human soul is the cause of literally all motion of everything else besides itself. This statement would thus make much more since if applied to “God” or some other Ultimate Being. Is it? I think it is intended as so. For skip ahead a few lines, and we have this likewise grandiose assertion: “And therefore the self-moving is the beginning of motion; and this can neither be destroyed nor begotten, else the whole heavens and all creation would collapse and stand still, and never again have motion or birth”. So whatever First Mover he’s talking about here, it apparently is responsible for upholding “the whole heavens and al creation” from collapse and annihilation, which is not something one would normally attribute to a human soul. So what exactly is he talking about?
I think, as I mentioned before, that he’s making a comparison between the “First Mover” of the universe as a whole and the “first mover” of particular living beings. In other words, I think he’s saying something like: just as there’s a cause of all motion in the universe, there must a similar sort of cause of the motion of living things. But this is just the first step in his argument. He then goes on to insist that anything that is a “self mover” as such must necessarily be immortal. I personally would question whether the soul is a true self mover, and hence whether it is immortal. But it is not difficult to see why Plato would think so.
Imagine an animal such as a lion walking. It might seem that the lion is “moving” itself, but as I suggested quite awhile ago in my first Prime Mover article, this is not entirely accurate. For the lion is made up of parts, and in order to move, its parts must work together in any orderly fashion. The lion as a whole may be able to “move” itself, but each individual part cannot. The movement of a single paw is dependent upon the movement of the leg. The movement of the leg is dependent upon the movement of muscle contractions. The muscle contractions are dependent upon and controlled by nerve impulses from the brain, which are caused by the firing of neurons. And we can keep tracing the causal series back. But, as indicated by this and similar passages, Plato seems to hold that such causal series in living things is just traced back to its soul. Instead of thinking in terms of nerve impulses and firing neurons, we might (if we wanted to follow in line with Plato) think in terms of the soul as that which directs the movements of the different parts of an animal or other living thing in accordance with the whole.
The distinction between the “ultimate” First Mover and the soul as first mover of living things is more evident in Cicero’s version. First, Cicero lays out pretty much the same argument for a First Mover, or as he calls it, a First Principle, as Plato. Then he comments that “the same [argument for the eternality of the first principle] must evidently apply to the human soul”. We can summarize his initial argument for the First Principle like this:
- All motion is either self moved or receives its motion from another
- If motion receives its motion from another, that other must be either self moved or likewise receive its motion from another
- This constitutes a causal series which must be traced back to some first principle of all motion, that does not receive its motion from another but is a “self mover”, causing its own motion
This is, in fact, a very simplistic, basic outline of Aristotle’s and later Aquinas’s own arguments from motion. Of course Aristotle and Aquinas made some very significant qualifications which, I think, rescue the argument from serious mistake, but it looks like we can credit Plato with at least the seed of an idea of more complete arguments from motion.
But why think this First Principle of motion is eternal? Cicero writes: “Being the first principle, it never had a beginning: since the first principle is what everything else has originated from, it cannot possibly have originated from anything itself. For if it owed its origins to something else, it could not be described as the first principle.” In other words, we’re appealing to this First Principle to explain all other motion that exists. It is the “origin” or cause of everything else. But if it itself began to exist, then it must have been caused by something else, and hence that something else will be the true First Principle, not it. So it could not have begun to exist. Plato’s argument that it furthermore cannot end to exist is essentially that, if it did end to cause, everything else that depends on it would also end to exist; but other things do exist, so it cannot have ended to exist. We might find this a bit wanting, since it seems to leave open the possibility of the First Principle ceasing to exist at some point in the future, which makes the use of the term “indestructible” somewhat unwarranted. Of course, there very well might be more to this, since the ancients had different understandings of necessity and indestructibility than we do. Specifically, we might see a hint of a deeper intention in his saying that “if unbegotten, it must also be indestructible; for if beginning were destroyed, there could be no beginning out of anything, nor anything out of a beginning”. What Cicero calls a First Principle Plato calls the “Beginning” of all things, and yet it itself is “unbegotten” or uncaused. But from what I just quoted, Plato seems to be suggesting that if something is destructible, it cannot properly be called a true “Beginning.” In other words, he might be maintaining that it is against the very nature of the First Mover to be susceptible of destruction or end.
Cicero draws this out more explicitly. He says, “If the first principle were destroyed it could never be reborn from any other source and would no longer be able to create things on its own account–which is obviously what the first principle has to do”. Basically, he’s just pointing out that it is in the very nature of the First Principle to cause other things, and it obviously could not do this if it were destroyed, and hence it is against the nature of the First Principle to be destroyed. The First Principle just is “that which has set itself in motion”, and it “can neither be born nor die”, for the First Principle as self mover is cause of all things, and if it itself were to be born or die, this would have to be accomplished by something other than itself. But since the First Principle by definition is the cause of all things, it cannot be moved or affected by anything external to itself. Thus, here, we see that Plato/Cicero had the slightest inkling of a conception of the First Mover as Pure Act, which it is necessary to conceive it as being in order for the argument to work.
Obviously, there are some major holes/weaknesses in their version of the argument which need to be worked out/developed more fully. But that’s just precisely what Aristotle and Aquinas did. In particular, as already noted, a key different would be between seeing the First Mover as “self moving” and the First Mover as immutable, causing motion but not undergoing any in itself (to consider how this is possible, see my article here).
But there’s one last interesting point from these passages I’d like to consider. Plato seems to intend the argument as a kind of analogy from the ultimate First Mover to the soul as a first mover of the living thing. But I wonder if we could reverse the argument, constructing it so that it argues in the opposite direction? In other words, would it perhaps be possible to argue from the soul as a kind of first mover to the ultimate First Mover as being, in a sense, a kind of “soul”? Obviously we need to be extremely careful here, especially in what we’re defining the soul as being. If we define, as Aristotle and Aquinas would, the soul specifically as the form of the body, then the argument I’m considering here wouldn’t work. But if we just define the soul as a principle of self motion in living things, then I think suddenly things become much more interesting.
Plato states: “The body which is moved from without is soulless; but that which is moved from within has a soul, for such is the nature of the soul.” Obviously, even living things are heavily influenced and affected by external causes. And even some non-living things might appear to have their cause of motion from some distinct part within themselves. But living things are distinctive in that there’s something about their motion which just appears to be self induced. Why did the chicken cross the road? Not because of gravity or some other external factor, but simply because it wanted to get to the other side. So however this works out in light of modern science, Plato just takes the soul to be whatever that principle of self motion actually is. And he takes this to mean that the soul must be immortal, because things that are self moved are not moved by anything other than themselves. Of course, Aquinas and Thomists would push back by insisting that the soul of a living thing is not entirely self moved. As we already noted, it just appears obvious that living things are in fact heavily influenced by outside causes. But even beyond this, we might argue that the souls of living things are finite; they certainly didn’t cause themselves, and so their potential for initial existence and for continuing to exist must be actualized by something else. In other words, since individual souls are not Pure Act, they by definition cannot be true First Movers, even if they do act as a kind of “secondary” first mover relative to that particular being itself.
So souls cannot be true first movers, but they might be a kind of relative first mover. And here is where we might draw an analogy. Just as the motion of living things is caused by the soul as principle of motion within it, we might suggest that the motion of all things, the entire universe, is caused by a “soul”of sorts.
Again, I must be extremely careful here because what I’m saying is immediately susceptible of drastic misinterpretation. I am not advocating any type of pantheism or panpsychism where the universe itself is a living thing with a soul (which is what Plato writes in Timaeus). What I’m rather suggesting (and it is admittedly a rather vague, not very much developed suggestion) is that we might have reason for thinking that whatever the First Principle of motion of the entire universe is, it might be analogous to the soul of living things in having a will/desire. In other words, I’m wondering if we might, on the basis of such an argument, have reason to attribute an analogous ability to “will” and “choose” to the First Mover of the whole universe. Of course, Aquinas already gives other, much more definitive reasons for concluding that, but I’m just playing around with Plato’s argument here and trying to draw out what its implications might be. In any case, it’s certainly an interesting passage, which is hardly surprising or rare in the works of such a mind as Plato’s.
. Plato. Phaedrus. Translated by Benjamin Jowett. Accessed online here: http://classics.mit.edu/Plato/phaedrus.html
. Cicero. “The Dream of Scipio” in On the Good Life. Translated by Michael Grant. Penguin Books, 1971. 353-354.
Header image in the Public Domain in the United States, taken from Wikimedia Commons: https://commons.wikimedia.org/wiki/File%3AFigura_dos_copy.jpg