Locke, Hume, Empiricism and the Existence of God
Both John Locke and David Hume claimed an empiricist epistemology, and both came to distinct conclusions with regard to the certitude with which God’s existence may be known. In the following, we will explore their respective arguments for the existence of God, as presented in Locke’s Essay Concerning Human Understanding (1690) and Hume’s Inquiry Concerning Human Understanding (1748). It will be concluded that while Locke’s argument is more persuasive, Hume’s is more consistent with a strict empiricism.
Locke presents two arguments for the existence of God. His first argument is a form of the cosmological argument: I exist (4:10:2); I cannot exist ex-nihilo; therefore something produced me (4:10:3), which is eternal (4:10:8), self-caused, or just happened to come into existence. The latter two are absurd, hence something eternal created me—God. Furthermore, Locke contends that God is omniscient (4:10:11ff.) and almighty (4:10:4), though these latter two claims are not the consequence of as rigorous a logical process as his initial argument. More plausible is his argument that the eternal God must have the capacity for cognition, since mind is distinct from matter, and the latter cannot produce the former (4:10:10).
On the other hand, in section 11 of his Inquiry, David Hume—hiding behind an anonymous interlocutor who claims sympathy with the Epicureans—comes to a rather different conclusion with regard to the existence of God. According to Hume, the only possible proof for God’s existence must be empirical proof. Since the strongest such argument for the existence of God is the argument from design, he chooses this as the subject of his scrutiny.
Hume begins by laying down the principle that we can ascribe capacities to a cause (God) only if they are evident in the effect (the world). Such being the case, we have no reason whatever to infer an almighty and all-good God from the world; the world is manifestly finite and imperfect, and any argument from such an effect to a God with the above properties is wholly unwarranted. Hume goes on to claim that the hypothesis of a God is useless. There is no practical gain in positing such a being, for, e.g., if justice is already present in the world, we do not need God; if it is not present, we cannot infer a just God; if justice is present in part, our inference cannot exceed the evidence. And in any case, we affirm justice for its own sake, regardless of whether or not there is a God.
Speaking in his own name, Hume advances as an objection to the argument listed above the following: might it not be the case that, just as we can infer a capable architect from a home that isn’t yet complete, and just as we can infer a whole man from a single footprint in the sand, so too we are justified in inferring an infinite being, even though his effect does not prove the point? The interlocutor responds that this would be an unwarranted inference. We are right to infer an architect from an incomplete home because we have experience of such things in our lives, but whenever has anyone experienced an infinite being? The interlocutor then repeats his chief principle at length—that we can ascribe a property to a cause only if it is evident in the effect, and the dialogue ends with Hume tentatively accepting the principle while allowing the possibility of the existence of a God.
So, who was right between Locke and Hume, and who was the true empiricist? Though Locke claimed that all of our thoughts are ideas gained from experience (sense perceptions or reflection on our own thought processes), his claim with regard to degrees of knowledge would seem to be at odds with this, for he claims that intuitive knowledge is the surest, demonstrative the second surest, and sensory the least sure. Hence, when he claims that the existence of God can be known with mathematical certainty (4:10:1), it would seem that this claim comes at the expense of a strict empiricism. Indeed, he later affirms this—the point of departure for our knowledge of God comes from the intuition of our own existence (4:11:1). So, while Locke’s proof for the existence of God is grounded in what he claims to be the surest degree of knowledge, it is open to question whether or not he has left the field of empiricism in order to do so.
Hume, on the other hand, is thoroughly consistent with his empiricism (Inquiry, section 7)—even to a fault. Hume will have none of the lofty speculation which philosophers of the past have fallen into (12): We must stay on the ground, and use as evidence only that which we have experienced. Hume does not once draw an inference beyond the bare minimum of what the evidence of the world requires. Therefore, with regard to their views on the existence of God, it is certainly the case that Hume proved himself the true empiricist.
That said, I myself find Hume’s argument wholly unconvincing. The principal difficulty I have is that the claim that we can posit a property in a cause only if the effect necessitates our doing so, is backwards. Whereas we must ascribe to a cause at least those capacities which are required for the realization of the effect, we have no reason whatever to claim that the cause can have only those properties. The response of the interlocutor to Hume’s criticism is simply a restrictive abuse of analogy—surely, insofar as W (the world) resembles W1 (an unfinished building), we are required to posit an M (maker of the world) that corresponds to M1 (the architect of the unfinished building). Locke, on the other hand, seems to have been justified in his central claim that mind cannot come from matter, and therefore, since it exists, it must be an irreducible, and therefore eternal principle of reality. If he had to stretch his empiricism to the breaking point in order to affirm this, so much the worse for his empiricism.