by Carl Sagan
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 apparitions 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 corn passionate.
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. [5]
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 of 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. [6]
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 that 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?