A Critique of Lawrence Krauss’ A Universe from Nothing (Review)
A Universe from Nothing
Physicist Lawrence Krauss’ recent book, A Universe from Nothing: Why There Is Something Rather than Nothing, provides a fine summary of modern cosmology. But Krauss’ fundamental purpose for writing the book is to use this summary to attempt to solve more philosophical and religious disputes. Krauss promotes the idea that science gives us the truth about the world, not philosophy or theology, and he defends this idea by arguing for the two primary contentions of his book:
His first contention is that science can answer the question age-old philosophical question, “Why is there something rather than nothing?”, by describing how our universe could have come from nothing:
The purpose of this book is simple. I want to show how modern science, in various guises, can address and is addressing the question of why there is something rather than nothing: The answers that have been obtained…all suggest that getting something from nothing is not a problem. Indeed, something from nothing may have been required for the universe to come into being. Moreover, all signs suggest that this is how our universe could have arisen. (p. xiii)
Krauss recognizes the “philosophical or religious” nature of this question, and acknowledges that it is often used to argue that our universe must have “design, intent, or purpose” (p. xiii). But because he believes that our universe’s arising from nothing is a purely physical process able to be described scientifically, he is hostile to the notion that this question has supernatural implications, which leads to his second contention: the existence of God is not necessary to explain why our universe exists. In the first line of the book he notes:
In the interests of full disclosure right at the outset I must admit that I am not sympathetic to the conviction that creation requires a creator, which is at the basis of all the world’s religions. (p. xi)
The main thesis of his book, therefore, is the merging of these two contentions together in the claim that science can show how the universe could have come from nothing, making the idea of God unnecessary.
In this article I argue that Krauss main thesis is false, and that the two primary contentions of his book fail. (All quotations of Krauss are taken from his book A Universe from Nothing.)
Why is there something rather than nothing?
Before doing this, however, it is necessary to provide a bit of background on the historic question of why there is something rather than nothing. This is a question made famous by the philosopher and polymath G. W. Leibniz, who contrary to Krauss, came to highly religiously significant conclusions while pondering it.
In a nutshell, Leibniz’ view was that the existence of something rather than nothing must have a reason — an explanation — and that this explanation could either invoke contingent things (things that could have failed to exist) or a necessary being (a being that could not have failed to exist).
Leibniz argued that contingent things cannot ultimately explain why the universe exists: for even if one thing was explained in terms of a second, and the second thing explained in terms of a third, and so on, ultimately there will be no explanation for why the whole series of things exists rather than nothing at all. Thus, a transcendent necessary being — whose existence is explained in terms of the necessity its own nature — is required to explain the existence of the universe.
And Leibniz concluded that the best candidate for a being such as this is God.
With this background to the question set up, it is easy to see the stark contrast between Leibniz’s answer and Krauss’. In fact, Krauss begins his treatment by reformulating the question itself, holding that science has informed it and changed the meaning of the words. He points out that “why” questions imply purpose and are thus unscientific; rather, the fruitful questions to ask are “how” questions. Hence, the real question that Krauss seeks to answer is, “How is there something rather than nothing?” (p. 144).
With this reformulation complete, he sets out to show two primary ways in which science demonstrates how something can come from nothing: first, our universe as we know it today arose from the energy of empty space; and second, our space-time itself may have arisen from a prior quantum state. Given these two demonstrations of Krauss’ first contention, he holds that this second contention follows as well — that any need for God to create the universe is removed. Let us consider these steps in turn.
A Universe from Empty Space?
Krauss spends the majority of chapters 1-9 of his book setting up the modern cosmological framework necessary to establish that the current state of our universe most plausibly arose from the quantum vacuum, or what Krauss calls empty space with energy. He summarizes his argument as follows:
The observation that the universe is flat and that the local Newtonian gravitational energy is essentially zero today is strongly suggestive that our universe arose through a process like that of inflation, a process whereby the energy of empty space (nothing) gets converted into the energy of something, during a time when the universe is driven closer and closer to being essentially flat on all observable scales. (p. 152)
This process of inflation, which takes us right back to the earliest moments of the universe (i.e., 10^43 seconds after the Big Bang), is caused by quantum fluctuations within otherwise empty space (which, according to Krauss, is “essentially nothing”; p. 98). This energy of empty space (also known as the cosmological constant or dark energy) is responsible for producing both the stuff out of which the universe is made and the structure it takes.
All that to say, Krauss recognizes that this is not quite a true example of something from nothing, admitting that “it would be disingenuous to suggest that empty space endowed with energy…is really nothing” (p. 152).
A Universe from Prior Quantum States?
This leads to Krauss’ second example of something from nothing, where he argues that quantum mechanics can be applied to space-time to open up the possibility that “space itself is forced into existence” (p. 161). To do this, Krauss first considers Richard Feynman’s “sum over paths formalism” of quantum mechanics, where one must take into account every possible trajectory a particle might take at a given point in order to make probabilistic predictions for how it will move.
Furthermore, Krauss notes that on Feynman’s method the results obtained “can be shown to be independent of the specific space and time labels one applies to each point on each path” (p. 162). Thus, this method can be extended to describe different possible space-times as well:
If we are to consider the quantum dynamics of space and time then, one must imagine that in the Feynman “sums,” one must consider every different possible configuration that can describe the different geometries that space can adopt during the intermediate stages of any process, when quantum indeterminacy reigns supreme. (p. 163)
(The branch of physics that deals with these sorts of applications is known as Quantum Field Theory.)
Krauss goes on to say that it is “most reasonable [to] consider the possibility of small, possibly compact spaces that themselves pop in and out of existence” (p. 163). Hence, our inflating universe (i.e., our space-time) may be a possible trajectory into which a prior quantum state evolved.
But the key point is this: in quantum mechanics, every possible state actually obtains. In other words, every possible quantum description of the world is a true description of some actually existing world, even if it be entirely disconnected from our own. Since one possible description is of our space-time’s arising from this prior quantum state, this view implies that it would actually exist. (Note that this requires a many-worlds or multiverse interpretation of quantum mechanics.)
So Krauss concludes that this quantum gravity model not only allows for the possibility of the creation of our universe from nothing (“nothing” here meaning “the absence of space and time”), but may even require it (p. 170).
The Need for God Removed?
Krauss is quick to concede that he hasn’t proven that this scenario is true; he merely maintains that he has shown it to be plausible. Nevertheless, this is all that is needed, he argues, to show that the existence of God is not necessary to explain how something comes from nothing.
But this only follows if Krauss has successfully demonstrated that there is a plausible scientific explanation of why there is something rather than nothing that does not invoke God. And it appears that he has not in fact demonstrated these philosophical contentions, even granting all of his purely scientific assertions.
In what follows, therefore, I will therefore grant that his picture of modern cosmology is correct, and that our universe could have come from these prior states that he describes. Nevertheless, I maintain that none of this shows that something can come from nothing, or that God is not required to explain our universe. Krauss therefore fails in supporting each of his two contentions.
Empty Space Is Not Nothing
The reason that Krauss fails to show how something can come from nothing is simple: all of the prior states he describes are something, not nothing. Nothing is a term of universal negation meaning “not anything.” This is the meaning of the term in the original question that Leibniz proposed.
However, all the examples Krauss gives are at best examples of something coming from another something, but perhaps with less physical properties. This is especially evident in his first example, where he admits that empty space with energy is something after all (p. 152). This first example by Krauss, then, self-admittedly fails at showing how something can come from nothing.
Prior Quantum States Are Not Nothing
Furthermore, his second example fails as well. Krauss certainly gives the impression that his second example is a true case of something from nothing by only describing this prior quantum state negatively (i.e., describing it as “the absence of space and time”; p. 170). There is more to this quantum state, however, than simply the absence of space and time, as philosopher David Albert recognizes: the state that Krauss describes is a state of “eternally persisting…relativistic quantum fields.” He continues:
According to relativistic quantum field theories, particles are to be understood…as specific arrangements of the fields. Certain arrangements of the fields, for instance, correspond to there being 14 particles in the universe…and certain other arrangements correspond to there being an infinite number of particles, and certain other arrangements correspond to there being no particles at all. And those last arrangements are referred to, in the jargon of quantum field theories…as “vacuum” states. Krauss seems to be thinking that these vacuum states amount to the relativistic-quantum-field-theoretical version of there not being any physical stuff at all. …But that’s just not right. Relativistic-quantum-field-theoretical vacuum states…are particular arrangements of elementary physical stuff. The true relativistic-quantum-field-theoretical equivalent to there not being any physical stuff at all isn’t this or that particular arrangement of the fields — what it is…is the simple absence of the fields! (Source article in the above link)
Thus, while Krauss may succeed in getting to a more fundamental physical state of reality, he does not reduce our space-time to an origin from literally nothing. Both of his examples therefore fail at demonstrating scientifically how something can come from nothing.
Much Ado about Nothing
Krauss anticipated this objection, arguing that “merely defining ‘nothingness’ as ‘nonbeing’ is not sufficient to suggest that physics, and more generally science, is not adequate to address the question” (p. 146).
But what Krauss seemingly fails to realize is that the original question itself means to ask why something exists rather than the absence of anything at all (i.e., “nonbeing”). The only way that he manages to answer the question scientifically is by changing it into a question that science can address, and by redefining “nothing” to include some physical state of affairs. But the word “nothing” plainly does not refer to a physical state of affairs, and the question that Krauss answers is not the original question.
Krauss complains that he is “told by religious critics that [he] cannot refer to empty space as ‘nothing,’ but rather as a ‘quantum vacuum,’ to distinguish it from the philosopher’s or theologian’s idealized ‘nothing’” (p. xiv). His complaining is unwarranted, however, because the philosophers and theologians are right. Elementary physical states are different from non-being, and it is this latter notion that is meant by “nothing” in the question that Leibniz made famous. This is why his question is considered a question of metaphysics; science is unable to answer this question in principle because there is no physics of non-being.
Conclusion: Krauss’ Contentions Fail
Krauss therefore fails in supporting his first contention. But it immediately follows from this that he fails to support his second contention as well. The principle reason Krauss gives for thinking that God is unnecessary to explain our universe is that the universe could have come from nothing by purely scientific means (p. 183). But given his failure to formulate a purely scientific explanation for why the universe exists, we may still wonder if a metaphysically necessary being is required after all. The two primary contentions of Krauss’ book therefore fail.
You may consider Krauss’ case for yourself in greater detail through reading his book A Universe from Nothing.
What do you think about Krauss’ two contentions? Do you agree or disagree with this critique of them? Leave any thoughts or questions you have in the comments below!