The question of the existence of God is a most important question and I'm very interested in presenting arguments bearing on this matter. The position I'm defending is that it's reasonable to believe that God does not exist.
I want to begin by briefly indicating how I'm going to understand the term 'God' in this next discussion. My view is that the question one should ask is, "What characteristics should an object possess in order to be an appropriate object of religious attitudes?"
I think that the answer to that is that a being, to be characterizable as God in that sense, should be a personal being, should be a being that is morally perfect, a being that is omnipotent, and a being that is omniscient. And I'm going to claim that it's unreasonable to believe in the existence of such a being.
There are four arguments that I'm going to offer, namely: (1) An argument for the view that atheism is the default position; (2) An argument that involves an extrapolation from the minds that we know; (3) An argument from the apparent hiddenness of God; and (4) A version of the argument from evil. I'm going to actually sketch the first one very briefly. The reason is that the other three are more important and since I haven't been permitted by Dr. Craig to transfer time from my second presentation to my first, I don't want to be forced to halt in the middle of my fourth argument. I will then use any time I have left to return to my first argument.
The central claim in the first argument is that atheism is the default position, and what that means is that, if there is no evidence in support of the existence of God, then it is reasonable to believe that God does not exist. The essential line of thought which I would hope to develop later on is that if you consider other things like fairies, leprechauns, golden teacups orbiting around Venus, and so on, I would suggest that we have no evidence against the existence of those sorts of things, but if I asked you whether you were agnostic I think the answer would be "no." You would believe there are no fairies, no leprechauns, no golden teacups orbiting around Venus. That illustrates the general principle in regard to God's existence that the burden of proof must fall upon the person who is arguing in support of God's existence. If there's no positive support for it, then the other side wins by default.
Let us now move on to my second argument. It involves an extrapolation from the nature of the minds that we know, and it turns upon the following thesis:
All minds that it is generally agreed that we are definitely acquainted with---namely the minds of humans and other animals---are either purely physical in nature or else are causally dependent on something physical in nature.
Now, one reason that we have for accepting this claim consists of facts that point toward at least a very intimate relationship between mental states and brain states. Among the facts that are relevant here are the following:
First, when an individual's brain is put into a certain physical state by direct stimulation, this causes the individual to have a corresponding experience, or, more generally, to be in some corresponding mental state.
Secondly certain types of damage to the brain make it impossible for one to enjoy any mental states at all---either temporarily or permanently, depending on the nature of the damage.
Thirdly, damage to the brain destroys various mental capacities, and which capacity is affected depends upon the particular region of the brain where it was damaged.
Fourthly, the mental capacities possessed by animals of other species become increasingly complex and impressive as the brain becomes more complex.
Fifthly, in the case of individuals belonging to a single species, the development of mental capacities is correlated with the development of neuronal circuitry in the relevant regions of the brain.
So in short, there is a good deal of evidence which indicates that there is a very close relationship between mental states and mental capacities and the development of the states of the brain.
Many contemporary philosophers and psychologists believe that the proper conclusion is that the mind is in fact purely physical: it is identical with the brain. Other philosophers and psychologists hold that this conclusion is too strong, and that the mind, rather than being identical with the brain, is instead causally dependent upon it. For the purpose of our discussion tonight though, for the present argument, it doesn't matter which of these views is the right one since, regardless of whether the mind is actually identical with the brain or merely causally dependent upon it, we can draw the following conclusion: To wit, none of the minds with which we are definitely acquainted can exist independently of physical arrangements of matter. All the minds that we are definitely acquainted with have a material basis.
If this conclusion is correct, it would seem that we are justified in making a standard inductive extrapolation upon it and concluding that probably there is no mind that exists independently of some associated physical arrangement of matter that it is either identical with or at least causally dependent upon.
Now if one used the term 'God' to mean a being that is immaterial or spiritual then it would follow immediately that it is unlikely that such a God exists. I didn't incorporate that requirement into the definition of God I gave at the beginning but I think there is good reason for drawing the same conclusion nonetheless. The reason is that I think one can argue that, given what we know about the universe, it would be impossible for there to be a being that was omnipotent and omniscient and that was physical in nature. So it seems to me that, even if one does not hold that God is by definition immaterial, what we are presently justified in believing about the nature of minds with which we are acquainted makes it reasonable to believe that it is unlikely that God exists.
That's the second argument. My third argument is the argument from the apparent hiddenness of God, and it turns upon two claims. The first is that if it's true that God exists then that is a very important truth. The second is that if God exists, his existence is by no means as evident as it could be. So if God exists, he is to some extent hiding himself.
Now the first claim probably requires little in the way of defense since most people, I think, will readily grant that, if God exists, then that is a very important piece of information. And it is easy to see why people should take that view. For if God is defined as above, and God exists, then in the end justice will be done and good will triumph. Moreover if God exists then there's a real possibility that death is not the end of the individual's existence. And given that the existence of God has these other consequences, it seems only reasonable to hold that if God exists, that fact is a very important one.
What about the second claim---that is, the claim that if God exists, his existence is not as evident as it could be? Even most people who believe in the existence of God will grant that God's existence is not exactly obvious, since, if it were, people would be no more inclined to doubt or reject the claim that God exists than they would be to question the existence of tables and chairs, trees and the flowers, people and animals.
But while granting this, believers attempt to respond that there's nothing surprising about this. After all, God is immaterial; he has a mind and no body. This response, however, does not meet the point. The relevant claim was not that God's existence could be as evident as that of physical things. It was rather that the existence of God-or, at least, the existence of an omnipotent and omniscient person-could be more evident, indeed, much more evident than it presently is. And this latter claim can, I believe, be given very strong support, for it's easy to imagine events that could occur, and which are such that if they did occur, would be sufficient to convince any rational person of the existence of God---or at least of the existence of an omnipotent, omniscient person, if not a morally perfect one.
For example, we can imagine either a voice in the sky speaking different languages over different countries, or else a telepathic communication for all who request it, where the content of the communication involves information that is far in advance of what we now possess. It might involve, for example, solutions to problems that mathematicians have been working on unsuccessfully for centuries.
You could also imagine impressive displays of great power. A voice from the sky announces that the earth will disappear in exactly five minutes and then reappear on the other side of the solar system. This occurrence then takes place. If this sort of scenario were appropriately fleshed out, surely it would be true both that one would have excellent reason for believing that there is a being with unlimited knowledge and unlimited power, and that one would thereby have better evidence for the existence of God than one presently possesses.
The argument can now be put very briefly as follows: It is agreed that if it is true that God exists, this is a very important truth. It has been shown that the world could be such that the existence of God would be much more evident than it presently is. So if God exists, he is to some extent hiding his reality from us, and, thereby, is depriving many people of firm knowledge of a very important truth.
The crucial question is, "What explanation could be offered for this fact?" Various answers have been proposed-such as the idea that it is somehow crucial for there to be epistemic, or cognitive distance between ourselves and God. I believe that it can be argued that none of those answers is satisfactory. If that's right, then if God does in fact exist, his hiddenness is an extremely puzzling fact. In contrast, if God does not exist, there is of course no problem why the existence of God is not as evident as it might be.
The conclusion, accordingly, is that one should accept the belief that God does not exist, since that is the hypothesis that provides the best explanation of the fact that God's existence is much less evident than it could be.
My fourth argument is the argument from evil. This is also my final argument, as I'm afraid that I have only four arguments rather than six. (Actually I expected Dr. Craig to present about sixteen, so that it would have been a real challenge to answer all sixteen in about twelve minutes. But answering six in twelve minutes will itself be a bit of a challenge.)
Argument number four-sometimes also referred to as the argument from suffering-is the argument that most philosophers think constitutes the most powerful objection against belief in the existence of God. It's also, I think, the argument that is most easily appreciated even by people who are not trained in philosophy or religious studies.
The argument focuses upon the fact that the world appears to contain states of affairs that are bad or undesirable, and it asks, in effect, how the existence of such states of affairs are to he squared with the existence of God.
The argument has a number of different forms. In one well-known variation, it is advanced as an argument in support of the following claim: It is logically impossible for it to be the case both that there is evil and that God exists. That argument goes as follows: if God exists, he will want to eliminate evil since he is by definition morally perfect. Being omniscient, he will know about any evil that happens to exist, and being omnipotent, he will have the power to eliminate any evil. So if God exists, he will be willing and able to eliminate any evil that there is. Therefore, if God exists, there will not be any evil. But the world does contain evil. Therefore God does not exist.
Now that's a rather striking and initially it might seem like an impressive argument. But there are serious objections to it. So it's important to be clear that I'm not advancing any sort of claim that there's a contradiction between the existence of God and the existence of evil. What I am defending is the following more modest claim: There are some evils that actually exist in the world that make it very unreasonable to believe that God exists--not impossible, but very unreasonable.
When the argument from evil is understood in this way, it can be put roughly as follows:
First of all, isn't it true that there are a number of changes that can be made in our world or that could have been made in the past, that it is very reasonable to believe would probably have made the world a better place? Think about that question. Isn't it reasonable to believe, for example, that the world would be improved if a cure for cancer were discovered? Or a cure for mental illness? Or isn't it reasonable to believe that the world would have been a better place if a polio vaccine were discovered earlier than it was-say in the year 1900---so that all of the people paralyzed between 1900 and the time of the Salk vaccine wouldn't have been paralyzed? And isn't it reasonable to believe that the world would have been a better place if, say, Hitler had died of a stroke, before he had a chance to pursue some of his more ambitious undertakings?
Now note that I'm not claiming that these things couldn't possibly have made the world a better place. Perhaps if Hitler had died before having had the opportunity of implementing his 'final solution' to the Jewish problem' there might have been someone out of the several million people who would thereby have been spared who would have turned out to be a mad genius who would have constructed a doomsday machine and would have destroyed all of life on earth. That might have been the case. Similarly it might be the case that if a cure for cancer were discovered today the results would be that the world would be destroyed in two years by someone who would have died had the cure not been discovered. But these possibilities do nothing to undermine the claim that it's reasonable to believe that the changes in question are ones that would make the world a better place. If you discovered a cure for cancer you would surely not conclude that you should keep it secret on the grounds that it was possible that the cure might save the life of someone who would later go on to destroy the world.
Secondly, notice that it does not matter whether the changes in question are ones that are brought about by human action. Suppose that the ocean just happened to wash some shells up onto the shore in a pattern of some English sentences describing a cure for cancer. If those sentences turned out to be true and cancer was thereby eliminated from the world-by a fantastic accident rather than by human endeavor---it still would be very reasonable to believe that this would make the world a better place.
Suppose we have a person---let's call him John---who knows a cure for cancer, who is able to communicate it to mankind, but who refuses to do so. Given that it is reasonable to believe that knowledge of a cure for cancer would make the world a better place, what conclusions could we draw about our friend John? The answer would seem to be that either John has an unreasonable belief to the effect that making a cure for cancer known to mankind would not make the world a better place, or John's moral character is defective---not only does it fall short of moral perfection but John is far less good than the average person.
Similarly, suppose that some person, Mary, knew of Hitler's plans to kill several million people, and could have killed him, but refrained from doing so. Given that it is reasonable to hold that the death of Hitler would have made the world a better place, what conclusion could you draw regarding Mary? The answer, surely, is that either Mary had an unreasonable belief to the effect that the world would be a better place if Hitler were allowed to go ahead with his idea of killing several million people, or else Mary's moral character was grossly defective.
Suppose finally, that there is a single person who could have done these things and more: a person who knows of a cure for cancer who could communicate it to us; a person who could have killed Hitler or otherwise diverted him from his wicked ways; a person who could have told us how to eliminate polio; a person who could have stopped Stalin from having millions of people murdered; a person who could have eliminated mental illness; and so on through countless changes that it is very reasonable to believe would make, or have made, the world a better place. What conclusion could you draw concerning such an individual? The answer, surely, is that either that individual would have to have a large number of unreasonable beliefs---to the effect that the world would not be improved by the elimination of cancer or mental illness, that it would not be improved by the elimination of polio in 1900, that it would not be improved by stopping Stalin and Hitler before they had succeeded in killing millions---or else, that individual is not only far less good than the average person, but profoundly evil. And either way, such an individual could not be God, since he would have to be less than perfect either in regard to knowledge or in regard to moral character.
The argument can now be stated very briefly. If there were an omniscient, omnipotent being, it would certainly be capable of making the changes in question. As we have just seen, however, if it is reasonable to believe the changes in question would make the world a better place, then it is reasonable to believe that an individual who could make those changes, but who does not, could not be God. It therefore follows that if it is reasonable to believe those changes would make the world a better place, then it is reasonable to believe that any omniscient and omnipotent being who happens to exist cannot possibly be God. This means in turn that if it's reasonable to believe those changes would make the world a better place then it is reasonable to believe that God does not exist. But there are surely reasons to believe that eliminating cancer would make the world a better place, and similarly, that stopping Hitler would have made the world a better place. Therefore it's reasonable to believe that God does not exist. Thank you.