This is the weekly Q & A blog post by our Research Professor in Philosophy, Dr. William Lane Craig.

Question

Dr. Craig,

My question has to do with Alexander Vilenkin and his idea of a quantum nucleation as the explanation for the origin of the universe. His view that the universe came into existence by means of a quantum event without a quantum field, vacuum, or tunneling process, seems to me to be very strange. Then the question is pushed back a step to be what caused the nucleation since it could not have come from absolutely nothing, or could it? It seems that the same cosmologist that has published his work that supports the second premiss of the Kalam Cosmological Argument now seems to be saying that the universe can indeed pull itself up by its bootstraps through quantum mechanics. Is this because he doesn't want to have to concede to deistic implications from his own work on the incompleteness of spacetime in past directions or because he is right that quantum mechanics can indeed lead to spontaneous creation without a prior quantum mechanical state? Is this view credible? Does this quantum nucleation apply to the origin of the multiverse as well? And does it provide a naturalistic explanation for the origin of spacetime?

God Bless,

David

United States

Dr. William Lane Craig’s Response

While I do not wish for anyone to be a non-theist, I must confess that Alex Vilenkin’s being an agnostic about God is dialectically advantageous for the proponent of the kalām cosmological argument, since it pulls the rug from beneath anyone who claims that belief that the universe began to exist is due to one’s theological commitments or that dreaded disorder of “confirmation bias.” Vilenkin has no theological axe to grind concerning this scientific question and so can be ruthlessly objective.

To see Vilenkin’s view of the kalām cosmological argument, I heartily commend to you his recent popular article “The Beginning of the Universe” published in the online journal Inference. In this article Vilenkin interacts for the first time, to my knowledge, explicitly with the kalām cosmological argument, and his response is just fascinating. Vilenkin would deny, not the second premiss of the kalām cosmological argument that the universe began to exist, but rather its first premiss that if the universe began to exist, then the universe has a cause.

He explains,

Modern physics can describe the emergence of the universe as a physical process that does not require a cause. Nothing can be created from nothing, says Lucretius, if only because the conservation of energy makes it impossible to create nothing [sic; something?] from nothing. . . .

There is a loophole in this reasoning. The energy of the gravitational field is negative; it is conceivable that this negative energy could compensate for the positive energy of matter, making the total energy of the cosmos equal to zero. In fact, this is precisely what happens in a closed universe, in which the space closes on itself, like the surface of a sphere. It follows from the laws of general relativity that the total energy of such a universe is necessarily equal to zero. . . .

If all the conserved numbers of a closed universe are equal to zero, then there is nothing to prevent such a universe from being spontaneously created out of nothing. And according to quantum mechanics, any process which is not strictly forbidden by the conservation laws will happen with some probability. . . .

What causes the universe to pop out of nothing? No cause is needed.[1]

So Vilenkin’s view is that the universe did, indeed, as you put it, “come from absolutely nothing.” But let’s be careful here, David. That does not imply that “the universe can indeed pull itself up by its bootstraps through quantum mechanics.” For that metaphor implies that the universe is self-caused, whereas Vilenkin’s view is that it is uncaused. I won’t speculate on Vilenkin’s personal motivation for his view but shall restrict myself to commenting on the credibility of his claim that, as you put it, “quantum mechanics can indeed lead to spontaneous creation without a prior quantum mechanical state.”

I agree with you, David, that Vilenkin’s view is “very strange.” Grant the supposition that the positive energy associated with matter is exactly counter-balanced by the negative energy associated with gravity, so that on balance the energy is zero. Vilenkin’s key move comes with the claim that in such a case “there is nothing to prevent such a universe from being spontaneously created out of nothing.” Now this claim is a triviality. Necessarily, if there is nothing, then there is nothing to prevent the universe from coming into being. By the same token, if there is nothing, then there is nothing to permit the universe to come into being. If there were anything to prevent or to permit the universe’s coming into being, then there would be something, not nothing. If there is nothing, then there is nothing, period.

The absence of anything to prevent the universe’s coming into being from nothing does not imply the metaphysical possibility of the universe’s coming into being without a cause. To illustrate, if there were nothing, then there would be nothing to prevent God’s coming into being without a cause, but that does not entail that such a thing is metaphysically possible. It is metaphysically impossible for God to come into being without a cause, even if there were nothing to prevent it because nothing existed.

Vilenkin, however, infers that “no cause is needed” for the universe’s coming into being because the conservation laws would not prevent it and “according to quantum mechanics, any process which is not strictly forbidden by the conservation laws will happen.” (Vilenkin assumes that if there were nothing, then both the conservation laws and quantum physical laws would still hold. This is far from obvious, however, since in the absence of anything at all, it is not clear that the laws governing our universe would hold.) But even granted that the laws would still hold, why think that, given the laws of quantum mechanics, anything not strictly forbidden by the conservation laws will happen? The conservation laws do not strictly forbid God’s sending everyone to heaven, but that hardly gives grounds for optimism. Neither do they strictly forbid His sending everyone to hell, in which case both outcomes will occur, which is logically impossible, as they are logically contrary universal generalizations. The point can be made non-theologically as well: the conservation laws do not strictly forbid something’s coming into existence, but neither do they forbid nothing’s coming into existence, but both cannot happen. It is logically absurd to think that because something is not forbidden by the conservation laws, it will therefore happen.

Finally, Vilenkin’s inference that because the positive and negative energy in the universe sum to zero, therefore no cause of the universe’s coming into being is needed is hard to take seriously. This is like saying that if your debts balance your assets, then your net worth is zero, and so there is no cause of your financial situation! (Vilenkin would, I hope, not agree with Peter Atkins that because the positive and negative energy of the universe sum to zero, therefore nothing exists now, and so “Nothing did indeed come from nothing.”[2] For as Descartes taught us, I, at least, undeniably exist, and so something exists.) Christopher Isham, Britain’s premier quantum cosmologist, rightly points out that there still needs to be “ontic seeding” to create the positive and negative energy in the first place, even if on balance its sum is naught.[3]

Vilenkin’s interaction with the kalām cosmological argument is, as I say, fascinating because we see here so clearly how philosophical faux pas, not scientific mistakes, invalidate the objections of an eminent scientist to the argument. This should be an object lesson to all those who, like Stephen Hawking or Lawrence Krauss, naïvely think that philosophy is a sterile and irrelevant discipline compared to science. Philosophy can help all of us, including scientists, to avoid the logical mistakes and conceptual confusions that are all too prevalent in discussions taking place on the borderland of physics, metaphysics, and theology.

Notes

[1] Alexander Vilenkin, “The Beginning of the Universe,” Inference: International Review of Science 1/ 4 (Oct. 23, 2015), http://inference-review.com/article/the-beginning-of-the-universe. I add the comment “something?” because only that makes sense of Lucretius’ position, which Vilenkin means to reject. On Lucretius’ view, something cannot come from nothing. If Lucretius holds, as Vilenkin puts it, that “nothing can be created from nothing,” then obviously Lucretius does not believe that it is “impossible to create nothing from nothing.” I take this to be a slip on Vilenkin’s part, occasioned perhaps by the confusing use of double negatives. It would have been clearer to say, “Something cannot be created from nothing, says Lucretius, if only because the conservation of energy makes it impossible to create something from nothing. . . . There is a loophole in this reasoning,” etc.

[2] From our debate posted at http://www.reasonablefaith.org/debate-transcript-what-is-the-evidence-for-against-the-existence-of-god#_ftn5; cf. Peter Atkins, Creation Revisited (New York: W. H. Freeman, 1992).

[3] Christopher Isham, “Quantum Cosmology and the Origin of the Universe,” lecture presented at the conference “Cosmos and Creation,” Cambridge University, 14 July 1994.

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