This debate with Father Frederick C. Copleston (Jesuit Catholic priest) and Bertrand Russell (agnostic philosopher) was a Third Programmme broadcast of the British Broadcasting Corporation in 1948. Reprinted in several sources, the following is from Bertrand Russell On God and Religion edited by Al Seckel (Prometheus Books).
A DEBATE ON THE EXISTENCE OF GOD
Bertrand Russell [hereafter R:] and F.C. Copleston [hereafter C:]
C: As we are going to discuss the existence of God, it might perhaps be as well to come to some provisional agreement as to what we understand by the term “God.” I presume that we mean a supreme personal Being — distinct from the world and Creator of the world. Would you agree — provisionally at least — to accept this statement as the meaning of the term “God”?
R: Yes, I accept this definition.
C: Well, my position is the affirmative position that such a Being actually exists, and that His existence can be proved philosophically. Perhaps you would tell me if your position is that of agnosticism or of atheism. I mean, would you say that the non-existence of God can be proved?
R: No, I should not say that: my position is agnostic.
C: Would you agree with me that the problem of God is a problem of great importance? For example, would you agree that if God does not exist, human beings and human history can have no other purpose than the purpose they choose to give themselves, which — in practice — is likely to mean the purpose which those impose who have the power to impose it?
R: Roughly speaking, yes, though I should have to place some limitation on your last clause.
C: Would you agree that if there is no God — no absolute Being — there can be no absolute values? I mean, would you agree that if there is no absolute good that the relativity of values results?
R: No, I think these questions are logically distinct. Take, for instance, G. E. Moore’s Principia Ethica, where he maintains that there is a distinction of good and evil, that both of these are definite concepts. But he does not bring in the idea of God to support that contention.
C: Well, suppose we leave the question of good till later, till we come to the moral argument, and I give first a metaphysical argument. I’d like to put the main weight on the metaphysical argument based on Leibniz’s argument from “Contingency” and then later we might discuss the moral argument. Suppose I give a brief statement on the metaphysical argument and that then we go on to discuss it?
R: That seems to me to be a very good plan.
C: Well, for clarity’s sake, I’ll divide the argument into distinct stages. First of all, I should say, we know that there are at least some beings in the world which do not contain in themselves the reason for their existence. For example, I depend on my parents, and now on the air, and on food, and so on. Now, secondly, the world is simply the real or imagined totality or aggregate of individual objects, none of which contain in themselves alone the reason of their existence. There isn’t any world distinct from the objects which form it, any more than the human race is something apart from the members. Therefore, I should say, since objects or events exist, and since no object of experience contains within itself the reason of its existence, this reason, the totality of objects, must have a reason external to itself. And that reason must be an existent being.
Well, this being is either itself the reason for its own existence, or it is not. If it is, well and good. If not, then we must proceed further. But if we proceed to infinity in that sense, then there’s no explanation of existence at all. So, I should say, in order to explain existence, we must come to a Being which contains within itself the reason for its own existence, that is to say, which cannot not exist.
R: This raises a great many points and it’s not altogether easy to know where to begin, but I think that, perhaps, in answering your argument, the best point with which to begin is the question of a Necessary Being. The word “necessary” I should maintain, can only be applied significantly to propositions. And, in fact, only to such as are analytic — that is to say — such as it is self-contradictory to deny. I could only admit a Necessary Being if there were a being whose existence it is self-contradictory to deny. I should like to know whether you would accept Leibniz’s division of propositions into truths of reason and truths of fact. The former — the truths of reason — being necessary.
C: Well, I certainly should not subscribe to what seems to be Leibniz’s idea of truths of reason and truths of fact, since it would appear that, for him, there are in the long run only analytic propositions. [ It would seem that for Leibniz truths of fact are ultimately reducible to truths of reason. That is to say, to analytic propositions, at least for an omniscient mind. Well, I couldn’t agree with that. For one thing it would fail to meet the requirements of the experience of freedom. ] I don’t want to uphold the whole philosophy of Leibniz. I have made use of his argument from contingent to Necessary Being, basing the argument on the principle of sufficient reason, simply because it seems to me a brief and clear formulation of what is, in my opinion, the fundamental metaphysical argument for God’s existence.
R: But, to my mind, a “necessary proposition” has got to be analytic. I don’t see what else it can mean. And analytic propositions are always complex and logically somewhat late. “Irrational animals are animals” is an analytic proposition; but a proposition such as “This is an animal” can never be analytic. In fact, all the propositions that can be analytic are somewhat late in the build-up of propositions.
C: Take the proposition “if there is a contingent being then there is a Necessary Being.” I consider that that proposition hypothetically expressed is a necessary proposition. If you are going to call every necessary proposition an analytic proposition, then — in order to avoid a dispute in terminology — I would agree to call it analytic, though I don’t consider it a tautological proposition. But the proposition is a necessary proposition only on the supposition that there is a contingent being. That there is a contingent being actually existing has to be discovered by experience, and the proposition that there is a contingent being is certainly not an analytic proposition, though once you know, I should maintain, that there is a contingent being, it follows of necessity that there is a Necessary Being.
R: The difficulty of this argument is that I don’t admit the idea of a Necessary Being and I don’t admit that there is any particular meaning in calling other beings “contingent.” These phrases don’t for me have a significance except within a logic that I reject.