The Portable Atheist

CARL SAGAN The God Hypothesis

The Gifford Lectures are supposed to be on the topic of natural theology. Natural theology has long been understood to mean theological knowledge that can be established by reason and experience and experiment alone. Not by revelation, not by mystical experience, but by reason. And this is, in the long, historical sweep of the human species, a reasonably novel view. For example, we might look at the following sentence written by Leonardo da Vinci. In his notebooks he says, “Whoever in discussion adduces authority uses not intellect but rather memory.”

This was an extremely heterodox remark for the early sixteenth century, when most knowledge was derived from authority. Leonardo himself had many clashes of this sort. During a trip to an Apennine mountaintop, he had discovered the fossilized remains of shellfish that ordinarily lived on the ocean floor. How did this come about? The conventional theological wisdom was that the Great Flood of Noah had inundated the mountaintops and carried the clams and oysters with it. Leonardo, remembering that the Bible says that the flood lasted only forty days, attempted to calculate whether this would be sufficient time to carry the shellfish with them, even if the mountaintops were inundated. During what state in the life cycle of the shellfish had they been deposited?—and so on. He came to the conclusion this didn’t work, and proposed a quite daring alternative; namely, that over immense vistas of geological time the mountaintops had pushed up through the oceans. And that posed all sorts of theological difficulties. But it is the correct answer, as I think it’s fair to say it has been definitively established in our time.

If we are to discuss the idea of God and be restricted to rational arguments, then it is probably useful to know what we are talking about when we say “God.” This turns out not to be easy. The Romans called the Christians atheists. Why? Well, the Christians had a god of sorts, but it wasn’t a real god. They didn’t believe in the divinity of apotheosized emperors or Olympian gods. They had a peculiar, different kind of god. So it was very easy to call people who believed in a different kind of god atheists. And that general sense that an atheist is anybody who doesn’t believe exactly as I do prevails in our own time.

Now, there is a constellation of properties that we generally think of when we in the West, or more generally in the Judeo-Christian-Islamic tradition, think of God. The fundamental differences among Judaism, Christianity, and Islam are trivial compared to their similarities. We think of some being who is omnipotent, omniscient, compassionate, who created the universe, is responsive to prayer, intervenes in human affairs, and so on.

But suppose there were definitive proof of some being who had some but not all of these properties. Suppose somehow it were demonstrated that there was a being who originated the universe but is indifferent to prayer…. Or, worse, a god who was oblivious to the existence of humans. That’s very much like Aristotle’s god. Would that be God or not? Suppose it were someone who was omnipotent but not omniscient, or vice versa. Suppose this god understood all the consequences of his actions but there were many things he was unable to do, so he was condemned to a universe in which his desired ends could not be accomplished. These alternative kinds of gods are hardly ever thought about or discussed. A priori there is no reason they should not be as likely as the more conventional sorts of gods.

And the subject is further confused by the fact that prominent theologians such as Paul Tillich, for example, who gave the Gifford Lectures many years ago, explicitly denied God’s existence, at least as a supernatural power. Well, if an esteemed theologian (and he’s by no means the only one) denies that God is a supernatural being, the subject seems to me to be somewhat confused. The range of hypotheses that are seriously covered under the rubric “God” is immense. A naive Western view of God is an outsize, light-skinned male with a long white beard, who sits on a very large throne in the sky and tallies the fall of every sparrow.

Contrast this with a quite different vision of God, one proposed by Baruch Spinoza and by Albert Einstein. And this second kind of god they called God in a very straightforward way. Einstein was constantly interpreting the world in terms of what God would or wouldn’t do. But by God they meant something not very different from the sum total of the physical laws of the universe; that is, gravitation plus quantum mechanics plus grand unified field theories plus a few other things equaled God. And by that all they meant was that here were a set of exquisitely powerful physical principles that seemed to explain a great deal that was otherwise inexplicable about the universe. Laws of nature, as I have said earlier, that apply not just locally, not just in Glasgow, but far beyond: Edinburgh, Moscow, Peking, Mars, Alpha Centauri, the center of the Milky Way, and out by the most distant quasars known. That the same laws of physics apply everywhere is quite remarkable. Certainly that represents a power greater than any of us. It represents an unexpected regularity to the universe. It need not have been. It could have been that every province of the cosmos had its own laws of nature. It’s not apparent from the start that the same laws have to apply everywhere.

Now, it would be wholly foolish to deny the existence of laws of nature. And if that is what we are talking about when we say God, then no one can possibly be an atheist, or at least anyone who would profess atheism would have to give a coherent argument about why the laws of nat re are inapplicable.

I think he or she would be hard-pressed. So with this latter definition of God, we all believe in God. The former definition of God is much more dubious. And there is a wide range of other sorts of gods. And in every case we have to ask, “What kind of god are you talking about, and what is the evidence that this god exists?”

Certainly if we are restricted to natural theology, it is insufficient to say, “I believe in that sort of god, because that’s what I was told when I was young,” because other people are told different things about quite different religions that contradict those of my parents. So they can’t all be right. And in fact they all may be wrong. It is certainly true that many different religions are mutually inconsistent. It’s not that they just aren’t perfect simulacrums of each other but rather that they grossly contradict each other.

I’ll give you a simple example; there are many. In the Judeo-Christian-Islamic tradition, the world is a finite number of years old. By counting up the begats in the Old Testament, you can come to the conclusion that the world is a good deal less than ten thousand years old. In the seventeenth century, the archbishop of Armagh, James Ussher, made a courageous but fundamentally flawed effort to count them up precisely. He came to a specific date on which God created the world. It was October 23 in 4004 B.C., a Sunday.

Now, think again of all the possibilities: worlds without gods; gods without worlds; gods that are made by preexisting gods; gods that were always here; gods that never die; gods that do die; gods that die more than once; different degrees of divine intervention in human affairs; zero, one, or many prophets; zero, one, or many saviors; zero, one, or many resurrections; zero, one, or many gods. And related questions about sacrament, religious mutilation, and scarification, baptism, monastic orders, ascetic expectations, the presence or absence of an afterlife, days to eat fish, days not to eat at all, how many afterlives you have coming to you, justice in this world or the next world or no world at all, reincarnation, human sacrifice, temple prostitution, jihads, and so forth. It’s a vast array of things that people believe. Different religions believe different things. There’s a grab bag of religious alternatives. And there are clearly more combinations of alternatives than there are religions, even though there are something like a few thousand religions on the planet today. In the history of the world, there probably were many tens, maybe hundreds of thousands, if you think back to our hunter-gatherer ancestors when the typical human community was a hundred or so people. Back then there were as many religions as there were hunter-gatherer bands, although the differences between them were probably not all that great. But nobody knows, since, unfortunately, we have virtually no knowledge left of what our ancestors for the greatest part of the tenure of humans on this planet believed, because word-of-mouth tradition is inadequate and writing had not been invented.

So, considering this range of alternatives, one thing that comes to my mind is how striking it is that when someone has a religious-conversion experience, it is almost always to the religion or one of the religions that are mainly believed in his or her community. Because there are so many other possibilities. For example, it’s very rare in the West that someone has a religious-conversion experience in which the principal deity has the head of an elephant and is painted blue. That is quite rare. But in India there is a blue, elephant-headed god that has many devotees. And seeing depictions of this god there is not so rare. How is it that the apparition of elephant gods is restricted to Indians and doesn’t happen except in places where there is a strong Indian tradition? How is that apparit ons of the Virgin Mary are common in the West but rarely occur in places in the East where there isn’t a strong Christian tradition? Why don’t the details of the religious belief cross over the cultural barriers? It is hard to explain unless the details are entirely determined by the local culture and have nothing to do with something that is externally valid.

Put another way, any preexisting predisposition to religious belief can be powerfully influenced by the indigenous culture, wherever you happen to grow up. And especially if the children are exposed early to a particular set of doctrine and music and art and ritual, then it is as natural as breathing, which is why religions make such a large effort to attract the very young.

Or let’s take another possibility. Suppose a new prophet arises who claims a revelation from God, and that revelation contravenes the revelations of all previous religions. How is the average person, someone not so fortunate as to have received this revelation personally, to decide whether this new revelation is valid or not? The only dependable way is through natural theology. You have to ask, “What is the evidence?” And it’s insufficient to say, “Well, there is this extremely charismatic person who said that he had a conversion experience.” Not enough. There are lots of charismatic people who have all sorts of mutually exclusive conversion experiences. They can’t all be right. Some of them have to be wrong. Many of them have to be wrong. It’s even possible that all of them are wrong. We cannot depend entirely on what people say. We have to look at what the evidence is.

I would like now to turn to the issue of alleged evidence or, as they’re called, proofs of the existence of God. And I will mainly spend my time on the Western proofs. But to show an ecumenical spirit, let me begin with some Hindu proofs, which in many ways are as sophisticated and certainly more ancient than the Western arguments.

Udayana, an eleventh-century logician, had a set of seven proofs of the existence of God, and I won’t mention all of them; I’ll just try to convey a sense of it. And, by the way, the kind of god that Udayana is talking about is not exactly the same, as you might imagine, as the Judeo-Christian-Islamic god. His god is all-knowing and imperishable but not necessarily omnipotent and compassionate.

First, Udayana reasons that all things must have a cause. The world is full of things. Something must have made those things. And this is very similar to a Western argument that we’ll come to shortly.

Secondly, an argument not heard in the West is the argument from atomic combinations. It is quite sophisticated. It says at the beginning of Creation, atoms had to be bonded with each other to make bigger things. And such a bonding of atoms always requires the activity of a conscious agent. Well, now we know that’s false. Or we know, at least, that there are laws of atomic interaction that determine how atoms bind together. It’s a subject called chemistry. And you might say that this is due to the intervention of a deity but it does not require the direct intervention of a deity. All the deity has to do is establish the laws of chemistry and retire.

Third is an argument from the suspension of the world. The world isn’t falling, as is clear by just looking out. We’re not hurtling through space, apparently, and therefore something is holding the world up, and that something is God. Well, this is a quite natural view of things. It’s connected with the idea that we are stationary and at the center of the universe, a misapprehension that all peoples all over the world have had. In fact we are falling at a terrific rate of speed in orbit around the Sun. And every year we go 2 pi times the radius of the Earth orbit. If you work that out, you’ll find it’s extremely fast.

Fourth is an argument from the existence of human skills. And this is very close to the von Daniken argument that if someone didn’t show us how to do things, we wouldn’t know how to do it. I think there’s plentiful argument against that.

Then there is the existence of authoritative knowledge separate from human skills. How would we know things that are in, for example, the Vedas, the Hindu holy books, unless God had written them? The idea that humans were able to write the Vedas was difficult for Udayana to accept.

Well, this gives a sense of these arguments and shows that there is a pervasive human wish to give a rational explanation for the existence of a God or gods, and also, I maintain, it demonstrates that these arguments are not always highly successful. Let me now go to some of the Western arguments, which may be entirely familiar to everyone, in which case I apologize.

First of all, there is the cosmological argument, which is not very different from the argument we just heard. The cosmological argument in the West essentially has to do with causality. There are things all around us; those things were caused by something else. And so, after a while, you find yourself back to remote times and causes. Well, it can’t go on forever, an infinite regress of causes, as Aristotle and later Thomas Aquinas argued, and therefore you need to come to an uncaused first cause. Something that started everything going that was not itself caused; that is, that was always there. And this is defined as God.

There are two conflicting hypotheses here, two alternative hypotheses. One is that the universe was always here, and the other is that God was always here. Why is it immediately obvious that one of these is more likely than the other? Or, put another way, if we say that God made the universe, it is reasonable to then ask, “And who made God?”

Virtually every child asks that question and is usually shushed by the parents and told not to ask embarrassing questions. But how does saying that God made the universe, and never mind asking where God came from, how is that more satisfying than to say the universe was always here?

In modern astrophysics there are two contending views. First of all, there is no doubt in my mind, and I think almost all astrophysicists agree, that the evidence from the expansion of the universe, the mutual recession of the galaxies and from what is called the three-degree black-body background radiation, suggests that something like 13 or 15 billion years ago all the matter in the universe was compressed into an extremely small volume, and that something that can surely be called an explosion happened at that time, and that the subsequent expansion of the universe and the condensation of matter led to galaxies, stars, planets, living beings, and all the rest of the details of the universe we see around us.

Now, what happened before that? There are two views. One is “Don’t ask that question,” which is very close to saying that God did it. And the other is that we live in an oscillating universe in which there is an infinite number of expansions and contractions.[10]

We happen to be roughly 15,000 million years out from the last expansion. And some, let’s say, 80,000 million years from now, the expansion will stop, to be replaced by a compression, and all the matter will fly together to a very small volume and then expand again with no information trickling through the cusps in the expansion process.

The former of these views happens, by chance, to be close to the Judeo-Christian-Islamic view, the latter close to the standard Hindu views. And so, if you like, you can think of the varying contentions of these two major religious views being fought out on the field o contemporary satellite astronomy. Because that’s where the answer to this question will very likely be decided. Is there enough matter in the universe to prevent the expansion from continuing forever, so that the self-gravity will make the expansion stop and be followed by a contraction? Or is there not enough matter in the universe to stop the expansion, so everything keeps expanding forever? This is an experimental question. And it is very likely that in our lifetime we will have the answer to it. And I stress that this is very different from the usual theological approach, where there is never an experiment that can be performed to test out any contentious issue.

Here there is one. So we don’t have to make judgments now. All we have to do is maintain some tolerance for ambiguity until the data are in, which may happen in a decade or less. It is possible that the Hubble Space Telescope, scheduled for launch next summer, will provide the answer to this question. It’s not guaranteed, but it is possible.[11]

Now, by the way, on this issue of who’s older, God or the universe, there’s actually a three-by-three matrix: God can have always existed but will not exist for all future time. That is to say God might have no beginning but might have an end. God might have a beginning but no end. God might have no beginning and no end. Likewise for the universe. The universe might be infinitely old, but it will end. The universe might have begun a finite time ago but will go on forever, or it might have always existed and will never end. Those are just the logical possibilities. And it’s curious that human myth has some of those possibilities but not others. I think in the West it’s quite clear that there is a human or animal life-cycle model that has been imposed on the cosmos. It’s a natural thing to think about, but after a while its limitations, I think, become clear.

Also, I should say something about the Second Law of Thermodynamics. An argument that is sometimes used to justify a belief in God is that the Second Law of Thermodynamics says that the universe as a whole runs down, that is, the net amount of order in the universe must decline. Chaos must increase as time goes on; that is, in the entire universe. It doesn’t say that in a given locale, such as the Earth, the amount of order can’t increase, and clearly it has. Living things are much more complex, have much more order in them, than the raw materials from which life formed some 4,000 million years ago. But this increase in order on the Earth is done, it is easy enough to calculate, at the expense of a decrease in order on the Sun, which is the source of the energy that drives terrestrial biology. It’s by no means clear, by the way, that the Second Law of Thermodynamics applies to the universe as a whole, because it is an experimental law, and we don’t have experience with the universe as a whole. But it’s always struck me as curious that those who wish to apply the Second Law to theological issues do not ask whether God is subject to the Second Law. Because if God were subject to the Second Law of Thermodynamics, then God could have only a finite lifetime. And again, there is an asymmetric use of the principles of physics when theology confronts thermodynamics.

Also, by the way, if there were an uncaused first cause, that by no means says anything about omnipotence or omniscience, or compassion, or even monotheism. And Aristotle, in fact, deduced several dozen first causes in his theology.

The second standard Western argument using reason for God is the so-called argument from design, which we have already talked about, both in its biological context and in the recent astrophysical incarnation called the anthropic principle. It is at best an argument from analogy; that is, that some things were made by humans and now here is something more complex th t wasn’t made by us, so maybe it was made by an intelligent being smarter than us. Well, maybe, but that is not a compelling argument. I tried to stress earlier the extent to which misunderstandings, failure of the imagination, and especially the lack of awareness of new underlying principles may lead us into error with the argument from design. The extraordinary insights of Charles Darwin on the biological end of the argument of design provide clear warning that there may be principles that we do not yet divine (if I may use that word) underlying apparent order.

There is certainly a lot of order in the universe, but there is also a lot of chaos. The centers of galaxies routinely explode, and if there are inhabited worlds and civilizations there, they are destroyed by the millions, with each explosion of the galactic nucleus or a quasar. That does not sound very much like a god who knows what he, she, or it is doing. It sounds more like an apprentice god in over his head. Maybe they start them out at the centers of galaxies and then after a while, when they get some experience, move them on to more important assignments.

Then there is the moral argument for the existence of God generally attributed to Immanuel Kant, who was very good at showing the deficiencies of some of the other arguments. Kant’s argument is very simple. It’s just that we are moral beings; therefore God exists. That is, how else would we know to be moral?

Well, first of all you might argue that the premise is dubious. The degree to which humans can be said to be moral beings without the existence of some police force is open at least to debate. But let’s put that aside for the moment. Many animals have codes of behavior. Altruism, incest taboos, compassion for the young, you find in all sorts of animals. Nile crocodiles carry their eggs in their mouths for enormous distances to protect the young. They could make an omelette out of it, but they choose not to do so. Why not? Because those crocodiles who enjoy eating the eggs of their young leave no offspring. And after a while all you have is crocodiles who know how to take care of the young. It’s very easy to see. And yet we have a sense of thinking of that as being somehow ethical behavior. I’m not against taking care of children; I’m strongly for it. All I’m saying is, it does not follow if we are powerfully motivated to take care of our young or the young of everybody on the planet, that God made us do it. Natural selection can make us do it, and almost surely has. What’s more, once humans reach the point of awareness of their surroundings, we can figure things out, and we can see what’s good for our own survival as a community or a nation or a species and take steps to ensure our survival. It’s not hopelessly beyond our ability. It’s not clear to me that this requires the existence of God to explain the limited but definite degree of moral and ethical behavior that is apparent in human society.

Then there is the curious argument, unique to the West, called the “ontological argument,” which is generally associated with [St.] Anselm, who died in 1109. His argument can be very simply stated: God is perfect. Existence is an essential attribute of perfection. Therefore, God exists. Got it? I’ll say it again. God is perfect. Existence is an essential attribute of perfection. You can’t be perfect if you don’t exist, Anselm says. Therefore God exists. While this argument has for brief moments captured very significant thinkers (Bertrand Russell describes how it suddenly hit him that Anselm might be right—for about fifteen minutes), this is not considered a successful argument. The twentieth-century logician Ernest Nagel described it as “confounding grammar with logic.”

What does it mean, “God is perfect”? You need a separate description of what constitutes perfection. It’s not enough to say “perfect” and do not ask what “perfect” means. And how do you know God is perfect? Maybe that’s not the god that exists, the perfect one. Maybe it’s only imperfect ones that exist. And then why is it that existence is an essential attribute of perfection? Why isn’t nonexistence an essential attribute of perfection? We are talking words. In fact, there is the remark that is sometimes made about Buddhism, I think in a kindly light, that their god is so great he doesn’t even have to exist. And that is the perfect counterpoise to the ontological argument. In any case, I do not think that the ontological argument is compelling.

Then there’s the argument from consciousness. I think, therefore, God exists; that is, how could consciousness come into being? And, indeed, we do not know the details in any but the very broadest brush about the evolution of consciousness. That is on the agenda of future neurological science. But we do know, for example, that an earthworm introduced into a Y-shaped glass tube with, let’s say, an electric shock on the right-hand fork and food in the left-hand fork, rapidly learns to take the left fork. Does an earthworm have consciousness if it is able after a certain number of trials invariably to know where the food is and the shock isn’t? And if an earthworm has consciousness, could a protozoan have consciousness? Many phototropic microorganisms know to go to the light. They have some kind of internal perception of where the light is, and nobody taught them that it’s good to go to the light. They had that information in their hereditary material. It’s encoded into their genes and chromosomes. Well, did God put that information there, or might it have evolved through natural selection?

It is clearly good for the survival of microorganisms to know where the light is, especially the ones that photosynthesize. It is certainly good for earthworms to know where the food is. Those earthworms that can’t figure out where the food is leave few offspring. After a while the ones that survive know where the food is. Those phototropic or phototactic offspring have encoded into their genetic material how to find the light. It is not apparent that God has entered into the process. Maybe, but it’s not a compelling argument. And the general view of many, not all, neurobiologists is that consciousness is a function of the number and complexity of neuronal linkages of the architecture of the brain. Human consciousness is what happens when you get to something like 10¹¹ neurons and 10¹⁴ synapses. This raises all sorts of other questions: What is consciousness like when you have 10²⁰ synapses or 10³⁰? What would such a being have to say to us any more than we would have to say to the ants? So at least it does not seem to me that the argument from consciousness, a continuum of consciousness running through the animal and plant kingdoms, proves the existence of God. We have an alternative explanation that seems to work pretty well. We don’t know the details, although work on artificial intelligence may help to clarify that. But we don’t know the details of the alternative hypothesis either. So it could hardly be said that this is compelling.

Then there’s the argument from experience. People have religious experiences. No question about it. They have them worldwide, and there are some interesting similarities in the religious experiences that are had worldwide. They are powerful, emotionally extremely convincing, and they often lead to people reforming their lives and doing good works, although the opposite also happens. Now, what about this? Well, I do not mean in any way to object to or deride religious experiences. But the question is, can any such experience provide other than anecdotal evidence of the existence of God or gods? One million UFO cases since 1947. And yet as far as we can tell, they do not correspond—any of them—to visitations to the Earth by spacecraft from elsewhere. Large numbers of people can have experiences that can be profound and moving and still not correspond to anything like an exact sense of external reality. And the same can be said not just about UFOs but also about extrasensory perception and ghosts and leprechauns and so on. Every culture has things of this sort. That doesn’t mean that they all exist; it doesn’t mean that any of them exist.

I also note that religious experiences can be brought on by specific molecules. There are many cultures that consciously imbibe or ingest those molecules in order to bring on a religious experience. The peyote cult of some Native Americans is exactly that, as is the use of wine as a sacrament in many Western religions. It’s a very long list of materials that are taken by humans in order to produce a religious experience. This suggests that there is some molecular basis for the religious experience and that it need not correspond to some external reality. I think it’s a fairly central point—that religious experiences, personal religious experiences, not the natural theological evidence for God, if any, can be brought on by molecules of finite complexity.

So if I then run through these arguments—the cosmological argument, the argument from design, the moral argument, the ontological argument, the argument from consciousness, and the argument from experience—I must say that the net result is not very impressive. It is very much as if we are seeking a rational justification for something that we otherwise hope will be true.

And then there are certain classical problems with the existence of God. Let me mention a few of them. One is the famous problem of evil. This basically goes as follows: Grant for a moment that evil exists in the world and that unjust actions sometimes go unpunished. And grant also that there is a God that is benevolent toward human beings, omniscient, and omnipotent. This God loves justice, this God observes all human actions, and this God is capable of intervening decisively in human affairs. Well, it was understood by the pre-Socratic philosophers that all four of these propositions cannot simultaneously be true. At least one has to be false. Let me say again what they are. That evil exists, that God is benevolent, that God is omniscient, that God is omnipotent. Let’s just see about each of them.

First of all, you might say, “Well, evil doesn’t exist in the world. We can’t see the big picture, that a little pool of evil here is awash in a great sea of good that it makes possible.” Or, as medieval theologians used to say, “God uses the Devil for his own purposes.” This is clearly the three-monkey argument about “hear no evil…” and has been described by a leading contemporary theologian as a gratuitous insult to mankind, a symptom of insensitivity and indifference to human suffering. To be assured that all the miseries and agonies men and women experience are only illusory. Pretty strong.

This is clearly hoping that the disquieting facts go away if you merely call them something else. It is argued that some pain is necessary for a greater good. But why, exactly? If God is omnipotent, why can’t He arrange it so there is no pain? It seems to me a very telling point.

The other alternatives are that God is not benevolent or compassionate. Epicurus held that God was okay but that humans were the least of His worries. There are a number of Eastern religions that have something like that same flavor. Or God isn’t omniscient; He doesn’t know everything; He has business elsewhere and so doesn’t know that humans are in trouble. One way to think about it is there are several times 10¹¹ worlds in every galaxy and several times 10¹¹ galaxies, and God’s busy.

The other possibility is that God isn’t omnipotent. He can’t do everything. He could maybe start the Earth off or create life, intervene occasionally in human history, but can’t be bothered day in and day out to set things right here on Earth. Now, I don’t claim to know which of these four possibilities is right, but it’s clear that there is a fundamental contradiction at the heart of the Western theological view produced by the problem of evil. And I’ve read an account of a recent theological conference devoted to this problem, and it clearly was an embarrassment to the assembled theologians.

This raises an additional question—a related question—and that has to do with microintervention. Why in any case is it necessary for God to intervene in human history, in human affairs, as almost every religion assumes happens? That God or the gods come down and tell humans, “No, don’t do that, do this, don’t forget this, don’t pray in this way, don’t worship anybody else, mutilate your children as follows.” Why is there such a long list of things that God tells people to do? Why didn’t God do it right in the first place? You start out the universe, you can do anything. You can see all future consequences of your present action. You want a certain desired end. Why don’t you arrange it in the beginning? The intervention of God in human affairs speaks of incompetence. I don’t say incompetence on a human scale. Clearly all of the views of God are much more competent than the most competent human. But it does not speak of omnicompetence. It says there are limitations.

I therefore conclude that the alleged natural theological arguments for the existence of God, the sort we’re talking about, simply are not very compelling. They are trotting after the emotions, hoping to keep up. But they do not provide any satisfactory argument on their own. And yet it is perfectly possible to imagine that God, not an omnipotent or an omniscient god, just a reasonably competent god, could have made absolutely clear-cut evidence of His existence. Let me give a few examples.

Imagine that there is a set of holy books in all cultures in which there are a few enigmatic phrases that God or the gods tell our ancestors are to be passed on to the future with no change. Very important to get it exactly right. Now, so far that’s not very different from the actual circumstances of alleged holy books. But suppose that the phrases in question were phrases that we would recognize today that could not have been recognized then. Simple example: The Sun is a star. Now, nobody knew that, let’s say, in the sixth century B.C., when the Jews were in the Babylonian exile and picked up the Babylonian cosmology from the principal astronomers of the time. Ancient Babylonian science is the cosmology that is still enshrined in the book of Genesis. Suppose instead the story was “Don’t forget, the Sun is a star.” Or “Don’t forget, Mars is a rusty place with volcanoes. Mars, you know, that red star? That’s a world. It has volcanoes, it’s rusty, there are clouds, there used to be rivers. There aren’t anymore. You’ll understand this later. Trust me. Right now, don’t forget.”

Or, “A body in motion tends to remain in motion. Don’t think that bodies have to be moved to keep going. It’s just the opposite, really. So later on you’ll understand that if you didn’t have friction, a moving object would just keep moving.” Now, we can imagine the patriarchs scratching their heads in bewilderment, but after all it’s God telling them. So they would copy it down dutifully, and this would be one of the many mysteries in holy books that would then go on to the future until we could recognize the truth, realize that no one back then could possibly have figured it out, and therefore deduce the existence of God.

There are many cases that you can imagine like this. How about “Thou shalt not travel faster than light”? Okay, you might argue that nobody was at imminent risk of breaking that commandment. It would have been a curiosity: “We don’t understand what that one’s about, but all the others we abide by.” Or “There are no privileged frames of reference.” Or how about some equations? Maxwell’s laws in Egyptian hieroglyphics or ancient Chinese characters or ancient Hebrew. And all the terms are defined: “This is the electric field, this is the magnetic field.” We don’t know what those are, but we’ll just copy them down, and then later, sure enough, it’s Maxwell’s laws or the Schrodinger equation. Anything like that would have been possible had God existed and had God wanted us to have evidence of His existence. Or in biology. How about, “Two strands entwined is the secret of life”? You may say that the Greeks were onto that because of the caduceus. You know, in the American army all the physicians wore the caduceus on their lapels, and various medical insurance schemes also use it. And it is connected with, if not the existence of life, at least saving it. But there are very few people who use this to say that the correct religion is the religion of the ancient Greeks, because they had the one symbol that survives critical scrutiny later on.

This business of proofs of God, had God wished to give us some, need not be restricted to this somewhat questionable method of making enigmatic statements to ancient sages and hoping they would survive. God could have engraved the Ten Commandments on the Moon. Large. Ten kilometers across per commandment. And nobody could see it from the Earth but then one day large telescopes would be invented or spacecraft would approach the Moon, and there it would be, engraved on the lunar surface. People would say, “How could that have gotten there?” And then there would be various hypotheses, most of which would be extremely interesting.

Or why not a hundred-kilometer crucifix in Earth orbit? God could certainly do that. Right? Certainly, create the universe? A simple thing like putting a crucifix in Earth orbit? Perfectly possible. Why didn’t God do things of that sort? Or, put another way, why should God be so clear in the Bible and so obscure in the world?

I think this is a serious issue. If we believe, as most of the great theologians hold, that religious truth occurs only when there is a convergence between our knowledge of the natural world and revelation, why is it that this convergence is so feeble when it could easily have been so robust?

So, to conclude, I would like to quote from Protagoras in the fifth century B.C., the opening lines of his Essay on the Gods: