For two thousand years the question of God has been asked and answered in the West within the framework of Christianity. This is only as it should be. With its unique belief in the fatherhood of God, as of a God who became man and shared the fate of criminals on crosses, Christianity created a moral conception of God which is arguably unsurpassed.
But this Christian conception of God, revealed in the pages of the New Testament, and capable of the philosophical sophistication we find in Augustine and Aquinas, did not spring from nowhere. It had roots not only in Jewish tradition but also in Greek philosophy. Tertullian in the third century demanded: What does Athens have to do with Jerusalem? But Athens had already made its way to Jerusalem when the documents of the New Testament were written and its voice can be detected in their pages. Now, at a time when Jerusalem is under siege and surrounded by scepticism, there is something to be gained from listening to Athens again. For the voice of Athens, though remote from us in time, is still one of reason. It speaks a language that not only believers but also sceptics can understand, if they have ears to hear.
The first voice that comes to us from Athens is that of Plato. Some of our current sceptics hold, not only that there is no God, but that belief in such a being is a sign of a mental disorder and fit only for ridicule. Richard Dawkins, who believes religiously, he tells us, in Darwin, calls belief in God a “delusion.” But even a cursory acquaintance with Plato should suffice to rid these skeptics of such an assumption, which can only be called ignorant. The father of philosophy, that is, of systematic rational thought and self-critical argument, was an ardent believer in the Gods. Or, as he sometimes says in the singular, “the God.” Belief in God or the Gods, for Plato, is not a matter of faith but of reason. He holds it is important to prove that the Gods exist, and he is confident that can be done. And it is important to prove in addition that they are good, and have more concern for justice than men do. It is possible to disagree with Plato; but it is not possible to dismiss him.
Of course, as their writings make plain, our current crop of atheists are not overwhelmingly interested in reasoned argument. A person who took reason seriously would be ashamed to make the superficial trains of thought that pass with them for arguments. Like the protagonists of the leftist political philosophy from which they spring, their basis is a certain moral stance which they feel to be self-authenticating and beyond the reach of rational doubt. This is why the left pay so little attention to genuine economics and even consider it evil. But back to Plato.
To our knowledge Plato was the first person in history to attempt to prove the existence of God or the Gods by purely rational argument. He was setting out on an untrodden path and we can see him feeling his way. He has three sources of thought he will try to combine: the traditions of the Greek myths, the common experience of the heavenly bodies, and the requirements of rational argument. But how to bring these into harmony with one another? The myths provide him with stories about the Gods which create their identities as they are known to history, yet he is deeply sceptical of these stories because of their low moral tone: they attribute to the Gods almost every imaginable crime. For Plato, philosophical thought begins from criticism of the myths. The heavenly bodies must have some relation to the Gods, for the Gods are the best explanation of their mysterious movements. And it is most important to make good arguments instead of bad. Those who disbelieve in the Gods not only lead men astray, but what is almost worse, they “make a bad and mistaken argument.”
He undertakes the task in Book X of his last and longest dialogue, Laws. The scene of the conversation is laid on the island of Crete, where two men, one from Crete and one from Sparta, are about to set out on a pilgrimage to the shrine of Zeus when they are joined by a third, the Athenian Stranger. The Cretan, Cleinias by name, has been given the task of drawing up the laws for a new colony, and the Athenian Stranger, who quickly takes charge of the conversation, leads the others into a detailed discussion of what those laws should be. He holds that the main task of a lawgiver is not so much to enforce the laws by coercion as to convince the people “by reasonable evidences” that the laws are right. The lawgiver, when he is making laws for men, should at the same time “infuse the spirit of persuasion into his words, and mitigate the severity of them as far as he can.” For this purpose every law should be provided with a prelude that sets out convincingly the reasons that justify it. The best of preludes to all laws would be the demonstration of the existence of the Gods. For belief in them is the best guarantee that a person will live rightly: “no one who in obedience to the laws believed that there were Gods ever intentionally did any unholy act, or uttered any unlawful word.”
Both in the Laws and also in the Republic, Plato is led to the question of God through the question of justice. Book IX of Laws concludes with a discussion of assault and violence. Book X, on the Gods, takes the argument up from that point. The law about violence can be summed up in this way: “No one shall take or carry away any of his neighbour’s goods, neither shall he use anything which is his neighbour’s without the consent of the owner.” These offences, Plato remarks, are the source of all evil, and are worst when they are done against religion. People who believe in the reality of justice will also believe in the reality of the Gods, he holds, and those who believe in the Gods will accept the objective reality of right and wrong. Those who commit crimes must either believe there are no Gods, or else that they are not concerned about men, or else that the Gods can be deflected from their purposes by the sacrifices men offer them. This pathway to the question of God through the question of morality is reminiscent in broad terms of that taken by Kant, and perhaps there is a more universal truth concealed in this.
Plato not only rejects atheism intellectually; he deplores it emotionally. Though basically his attitude towards them is humane, it angers him that there should be such stupid people. Atheists are “lost and perverted natures.” Atheism is a “disorder.” He is eager to show them where they are wrong, but also resents being put to this labor, which if men used their heads would be unnecessary . “Who can be calm when he is called upon to prove the existence of the Gods? Who can avoid hating and abhorring the men who are and have been the cause of this argument? … when men, knowing all these things, despise them on no real grounds, as would be admitted by all who have any particle of intelligence…how can anyone in gentle terms remonstrate with the likes of them, when he has to begin by proving to them the very existence of the Gods? Yet the attempt must be made.” Recovering and correcting himself, as it were, he remarks that our address to them should not be spoken in passion.
To the Dawkinses, Harrises and Hitchenses of this world he offers some fatherly advice, which, however, they will scarcely be pleased to hear: the passage of time will make them reverse many of the opinions they now hold. “No one who had taken up in his youth this opinion, that the Gods do not exist, ever continued in it until he was old.” They should wait a while, and not attempt to judge at present of the highest things. And that is the highest of which they now think nothing: to know the Gods rightly and to live accordingly. Atheism is a product of mental and emotional immaturity.
* * *
Advancing to the argument itself, Plato begins by laying out the worldview that leads his skeptics to a denial of God. It is one based on what we today would call naturalism or scientism (for it is the view of those he calls the “physical investigators”): it assumes that matter and material objects came first, and that life and mind and intelligence developed only later and out of them. His terminology makes a distinction between nature and “art” (τεχνη), meaning, not what is artistic, but the distinctive operation of mind as opposed to nature, as in “artifact.”
“They say that the greatest and fairest things are the work of nature and of chance…that fire and water, and earth and air, all exist by nature and chance, and none of them by art, and that as to the bodies which come next in order—earth, and sun, and moon, and stars—they have been created by means of these absolutely inanimate existences. The elements are severally moved by chance and some inherent force according to certain affinities among them — of hot with cold, or of dry with moist, or of soft with hard, and according to all the other accidental admixtures of opposites which have been formed by necessity. After this fashion and in this manner the whole heaven has been created, and all that is in the heaven, as well as animals and all plants, and all the seasons come from these elements, not by the action of mind, as they say, or of any God, or from art, but as I was saying, by nature and chance only.”
The atheists say the Gods have been created “by the laws of states, which are different in different places, according to the agreement of those who make them.” Consequently they reject the idea that there is a natural moral law; they hold “that the principles of justice have no existence at all in nature, but that mankind are always disputing about them and altering them; and that the alterations which are made by art and by law have no basis in nature, but are of authority for the moment and at the time at which they are made.” ..”that the highest right is might, and in this way the young fall into impieties, under the idea that the Gods are not such as the law bids them imagine; and hence arise factions, these philosophers inviting them to lead a true life according to nature, that is, to live in real dominion over others, and not in legal subjection to them.”
Plato now introduces a new term into the discussion, “soul” (ψυχη). By this word he means the principle of life in any living thing. The soul of a plant or animal or man is what makes the plant or animal or man alive. The realm of mind or art is therefore also the realm of soul, since to have a mind means one is alive. “Does not he who talks in this way conceive fire and water and earth and air to be the first elements of all things? These he calls nature, and out of these he supposes soul to be formed afterwards.” We will return to this concept shortly: it will play a central role. For the moment it will be helpful to understand that in speaking of soul he intends initially to speak not so much of some particular being, the soul, but of a unique kind of being, soul, without the definite article.
The immediate aim of his argument is to explain the existence of motion. This word has a broader meaning for him than for us. When we think of motion, we tend to think of motion in place, or from one place to another, locomotion. But for Plato, as later for Aristotle, “motion” can stand not only for locomotion, but for all kinds of motion, and by extension all kinds of change. This includes coming into being and passing away, generation and corruption, composition and decomposition, both what Aristotle would later call substantial change and accidental change. That is, “motion” for Plato includes the act of creation. If we can explain the origin of motion, we will have explained the origin of the universe. This is why St. Thomas begins his arguments also with what appears to be a question of physics.
Beginning then with the question of motion: “Some one says to me, ‘O Stranger, are all things at rest and nothing in motion, or is the exact opposite of this true, or are some things in motion and others at rest?’ To this I shall reply that some things are in motion and others at rest.” This might seem to us a strange question, but there were earlier thinkers in Greece, such as Parmenides and Zeno, who denied that there really was motion: it was a logical contradiction, they maintained, and must be an illusion. For they believed that fundamentally all reality was one, a single entity, and that the apparent existence of numerous beings must be mistaken. That was the point of Zeno’s parable of the tortoise and the hare: logically the hare could never catch the tortoise.
It is helpful in understanding what Plato and Aristotle and indeed all writers on motion say about it before Galileo, to know that they do not have the concept of inertia, which he was the first to develop. They assume that for an inanimate thing to keep moving, some external force must keep being applied to it. It was long a great puzzle therefore why a thrown stone should keep going once it has left the hand, or cannonballs should keep flying once they have left the area of the explosion, for it is not evident where this necessary external force might be. One explanation offered was that, once the cannonball is moving, the air must rush around from the front to the back of it and push it from behind. Galileo’s historic achievement was to realise that no such continuous external force is necessary: it is a law of nature that bodies that are once moving will keep moving, without any such force, just as bodies that are at rest will stay at rest, so long as no external force is applied to them. It was because they did not have the concept of inertia, which applies only to locomotion, that the ancients could lump all change together under the heading of “motion.” Einstein, of course, was to explain that all motion and rest of bodies is relative to other bodies. Although, as I say, it is helpful to understand this, it makes no difference to the validity of Plato’s argument about God.
After these preliminaries Plato now takes the first step of his argument proper. The Athenian Stranger makes a distinction between two very different kinds of motion. There is one kind of motion that can move other things but cannot move itself. And there is another kind that in addition to being able to move other things can also move itself.
Cleinias accepts this distinction. The Athenian now asks him: “And which of these…motions ought we to prefer as being the mightiest and most efficient? Cleinias replies, “I must say that the motion which is able to move itself is ten thousand times superior to all the others.”
The Athenian now takes the second step in his argument by asking: If at some time all things were at rest, which of these two principles of motion would first spring up among them? Cleinias answers, “Clearly the self-moving; for there could be no change in them arising out of any external cause; the change must first take place in themselves. The Stranger now clinches his argument. “Then we must say that self-motion being the origin of all motions, and the first which arises among things at rest as well as among things in motion, is the eldest and mightiest principle of change, and that which is changed by another and yet moves other is second.” The first motion in the universe must be self-motion. It is impossible that it should be the other kind.
One more step is required to complete the argument. The distinction between what can move only because it has been moved by something else and what has the power to move itself is precisely the distinction between non-life and life, the inanimate and the animate. Living beings have the power to move themselves, non-living beings do not. In the history of the universe or in the overall scheme of things, life must come before non-life. It makes no sense to think that life could evolve out of what is lifeless. The self-moving must necessarily come first. That is, soul. Soul, therefore, must be the origin of all things.
If this is true, says Plato, then it follows that the whole realm of mind will be prior to the realm of body, not only in time but also in dignity and importance. “Then thought and attention and mind and art and law will be prior to that which is hard and soft and heavy and light; and the great and primitive works and actions will be works of art; they will be the first, and after them will come nature and works of nature…” “these…will be under the government of art and mind.” “Then characters and manners, and wishes and reasonings, and true opinions, and reflections, and recollections are prior to length and breadth and depth and strength of bodies, if the soul is prior to the body.” Our view of the universe should give priority to the things of mind and the spirit.
We must be careful, then, how we speak of nature, says Plato. Many people who speak of nature assume that nature is the first creative power. But that is not true if soul exists first. If soul comes first, “then in the truest sense and beyond other things soul may be said to exist by nature.”
* * *
Is Plato’s argument valid?
The chief objection to it in the ancient world was raised by Aristotle, who argued that it is logically impossible for anything to move itself. What looks to our eyes like something moving itself, e.g. an animal that has been lying still getting up and walking around, is actually a case of one part of the animal, say the heart, which is already moving, moving another, say a leg. The heart gets its movement from the world around it, he thought, and that is ultimately moved by the First Mover. For on Aristotle’s account, change is always a transition from potentiality to actuality, and it is impossible for anything to actualize itself. Actualization must always come from something else that is actual. Aristotle believed in God or the Gods just as much as Plato did, but his explanation is different.
Aristotle’s account of motion in this regard is still the essential viewpoint of the scientific world, for scientific method in its present state cannot cope with the idea of life. Scientific explanations are either in terms of mechanical causation or else in quantum theory, and life is neither the one nor the other. Science has as yet no theory that would enable it to distinguish life from non-life. We can detect life by ordinary common sense, for we know many things that cannot be proven scientifically. And like us, scientists can detect life using their common sense. For as Plato states, only living things move themselves. But science as a discipline has until now proceeded reductively: it can only explain life by treating it as if it were non-life. The most interesting development in science in this regard is the theory of emergence that has been raised in recent years in physics. This recognizes that some events in nature can only be explained by factors that are higher or more complex than themselves rather than lower or simpler. But to explore this further would take us beyond the bounds of this short article.
I believe that Plato’s argument is valid. In the history of the universe, what has the power to move itself must come before that which can only be moved by something else. This means that life must come before non-life, and mind before non-mind.
Ath. And now, Megillus and Cleinias, let us offer terms to him who has hitherto denied the existence of the Gods, and leave him.
Cle. What terms?
Ath. Either he shall teach us that we were wrong in saying that soul is the origin of all things, and arguing accordingly; or, if he be not able to say anything better, then he must yield to us and live for the remainder of his life in the belief that there are Gods.
 A certin insouciance regarding the number of the Gods on the part of religious people was not uncommon. Aristotle leaves it to the astronomers to tell us, since it is for him a question of how many independent motions can be counted in the heavens. It seems to have been widespread custom to speak of many Gods, since the myths do so, but to assume that underneath that multiplicity there must be a single ultimate divine reality. This is still common in some existing traditions.
 See Robert B. Laughlin, A Different Universe: Reinventing Physics from the Bottom Down. New York, Basic Books, 2005.