Lawrence M. Krauss is a renowned cosmologist, popularizer of science, and director of the Origins Project at Arizona State University. He is the author of more than 300 scientific publications and 8 books, including the bestselling The Physics of Star Trek. His interests include the early universe, the nature of dark matter, general relativity and neutrino astrophysics. He is also a friend and an advisor to my nonprofit foundation, Project Reason. Lawrence generously took time to answer a few questions about his new book, A Universe from Nothing.
One of the most common justifications for religious faith is the idea that the universe must have had a creator. You’ve just written a book alleging that a universe can arise from “nothing.” What do you mean by “nothing” and how fully does your thesis contradict a belief in a Creator God?
Indeed, the question, “Why is there something rather than nothing?” which forms the subtitle of the book, is often used by the faithful as an unassailable argument that requires the existence of God, because of the famous claim, “out of nothing, nothing comes.” While the chief point of my book is to describe for the interested layperson the remarkable revolutions that have taken place in our understanding of the universe over the past 50 years—revolutions that should be celebrated as pinnacles of our intellectual experience—the second goal is to point out that this long-held theological claim is spurious. Modern science has made the something-from-nothing debate irrelevant. It has changed completely our conception of the very words “something” and “nothing”. Empirical discoveries continue to tell us that the Universe is the way it is, whether we like it or not, and ‘something’ and ‘nothing’ are physical concepts and therefore are properly the domain of science, not theology or philosophy. (Indeed, religion and philosophy have added nothing to our understanding of these ideas in millennia.) I spend a great deal of time in the book detailing precisely how physics has changed our notions of “nothing,” for example. The old idea that nothing might involve empty space, devoid of mass or energy, or anything material, for example, has now been replaced by a boiling bubbling brew of virtual particles, popping in and out of existence in a time so short that we cannot detect them directly. I then go on to explain how other versions of “nothing”—beyond merely empty space—including the absence of space itself, and even the absence of physical laws, can morph into “something.” Indeed, in modern parlance, “nothing” is most often unstable. Not only can something arise from nothing, but most often the laws of physics require that to occur.
Now, having said this, my point in the book is not to suggest that modern science is incompatible with at least the Deistic notion that perhaps there is some purpose to the Universe (even though no such purpose is manifest on the basis of any of our current knowledge, and moreover there is no logical connection between any possible “creator” and the personal God of the world’s major religions, who cares about humanity’s destiny). Rather, what I find remarkable is the fact that the discoveries of modern particle physics and cosmology over the past half century allow not only a possibility that the Universe arose from nothing, but in fact make this possibility increasingly plausible. Everything we have measured about the universe is not only consistent with a universe that came from nothing (and didn’t have to turn out this way!), but in fact, all the new evidence makes this possibility ever more likely. Darwin demonstrated how the remarkable diversity of life on Earth, and the apparent design of life, which had been claimed as evidence for a caring God, could in fact instead be arrived at by natural causes involving purely physical processes of mutation and natural selection. I want to show something similar about the Universe. We may never prove by science that a Creator is impossible, but, as Steven Weinberg has emphasized, science admits (and for many of us, suggests) a universe in which one is not necessary.
I cannot hide my own intellectual bias here. As I state in the first sentence of the book, I have never been sympathetic to the notion that creation requires a creator. And like our late friend, Christopher Hitchens, I find the possibility of living in a universe that was not created for my existence, in which my actions and thoughts need not bend to the whims of a creator, far more enriching and meaningful than the other alternative. In that sense, I view myself as an anti-theist rather than an atheist.
I’d like to linger on the concept of “nothing” for a moment, because I find it interesting. You have described three gradations of nothing—empty space, the absence of space, and the absence of physical laws. It seems to me that this last condition—the absence of any laws that might have caused or constrained the emergence of matter and space-time—really is a case of “nothing” in the strictest sense. It strikes me as genuinely incomprehensible that anything—laws, energy, etc.—could spring out of it. I don’t mean to suggest that conceivability is a guide to possibility—there may be many things that happen, or might happen, which we are not cognitively equipped to understand. But the emergence of something from nothing (in this final sense) does strike me as a frank violation of the categories of human thought (akin to asserting that the universe is a round square), or the mere declaration of a miracle. Is there any physical reason to believe that such nothing was ever the case? Might it not be easier to think about the laws of physics as having always existed?
That’s a very good question, and it actually strikes to the heart of one of the things I wanted to stress most in the book. Because a frank violation of the categories of human thought is precisely what the Universe does all of the time. Quantum mechanics, which governs the behavior of our Universe on very small scales, is full of such craziness, which defies common sense in the traditional sense. So small squares are sometimes round.. namely systems can be in many different states at the same time, including ones which are mutually exclusive! Crazy, I know, but true… That is the heart of why the quantum universe is so weird. So, yes, it would be easier to think about the laws of physics as always having existed, but “easy” does not always coincide with “true.” Once again, my mantra: The Universe is the way it is, whether we like it or not.
Now to hit the second part of your question… do we have any reason to suppose the laws themselves came into existence along with our universe? Yes… current ideas coming from particle physics allow a number of possibilities for multiple universes, in each of which some of the laws of physics, at least, would be unique to that universe. Now, do we have any models where all the laws (including even, say, quantum mechanics?) came into being along with the universe? No. But we know so little about the possibilities that this certainly remains one of them.
But even more germane to your question perhaps… do we have any physical reason to believe that such nothing was ever the case? Absolutely, because we are talking about our universe, and that doesn’t preclude our universe arising from precisely nothing, embedded in a perhaps infinite space, or infinite collection of spaces, or spaces-to-be, some of which existed before ours came into being, and some of which are only now coming into, or going out of existence. In this sense, the multiverse, as it has become known, could be eternal, which certainly addresses one nagging aspect of the issue of First Cause.
I want to keep following this line, because it seems to me that we rarely do it—and I think many people will be interested to learn how a physicist like yourself views the foundations of science. As you know, in every branch of science apart from physics we stand upon an inherited set of concepts and laws that explain the whole enterprise. In neuroscience, for instance, we inherit the principles of chemistry and physics, and these explain everything from the behavior of neurons to the operation of our imaging tools. As one moves “up” in science, the problems become more complex (and for this reason the science inevitably gets “softer”), and we find very little reason to contemplate the epistemological underpinnings of science itself. So I’d like you to briefly tell us how you and your colleagues view the fact that certain descriptions of reality might be true, and testable, but impossible to understand. I had thought, for instance, that most physicists were unsatisfied with the strangeness of QM and still held out hope that a more fundamental theory would put things right, yielding a picture of reality that we could truly grasp, rather than merely accede to. Is that not true?
Another deep and difficult question Sam! A full answer would probably take more room than we have here, and I have tried to address this issue to some extent both in A Universe from Nothing and my books Fear of Physics and Hiding in the Mirror. First of all, let me address the issue of “understanding.” There are aspects of the universe, such as the fact that three-dimensional space can be curved, which cannot be “understood” in an intuitive sense because we are three-dimensional beings. Just like the two-dimensional beings in the famous book Flatland, who had no idea how to truly picture a sphere, we cannot visualize a three-dimensional closed universe, for example. This does not stop us, however, from developing mathematics that completely describes such a universe. So, our mathematics can model such a universe and allow us to make predictions we can test, and therefore provide an “explanation” of the universe that is comprehensible, even if not intuitively understandable.
But there is something even more profound about the nature of “scientific truth” that has arisen in physics, which I don’t think is generally appreciated. It is the simple fact that we realize that none of our theories are “true” in the sense that they adequately describe nature on all scales. All of our physical theories, as we now understand them, have limited domains of validity, which we can actually quantify in an accurate way. Even Quantum Electrodynamics, which is the best tested theory in nature, allowing us to predict the energy levels of atoms to better than 1 part in a billion, gets subsumed in a more general theory, called the Electroweak theory, when it is applied to trying to understand the interactions of quarks and electrons on scales 100 times smaller than the size of protons. Now, as Richard Feynman emphasized, we have no idea if this process will continue, if we will peel back the layers of reality like an onion, whether the process will never end, or whether we will truly come up with a fundamental theory that allows us to extrapolate our understanding to all scales. As he pointed out, it doesn’t really matter, because what we scientists want to do is learn about how the universe works, and at each stage we learn something new. We may hope the universe has some fundamental explanation, but as I keep emphasizing, the universe is the way it is, whether we like it or not, and our job is to be brave enough to keep trying to understand it better, and to accept the reality that nature imposes upon us.
It is true that some physicists find the strangeness of Quantum Mechanics unsatisfying and suspect that it might be embedded in a more fundamental theory that seems less crazy. But hope and reality are not the same thing. Similarly, it may be intellectually unsatisfying to imagine that time began with our universe, so asking what came before is not a sensible question, or to imagine an eternal multiverse which itself was never created, or to never be able to empirically address the question of whether the laws of nature arose spontaneously along with the universe, but we have to keep plugging away regardless, motivated by the remarkable fact that nature has surprises in store for us that we never would have imagined!
Finally, it is the “how” question that is really most important, as I emphasize in the new book. Whenever we ask “why?” we generally mean “How?”, because why implies a sense of purpose that we have no reason to believe actually exists. When we ask “Why are there 8 planets orbiting the Sun?” we really mean “How are there 8 planets?”—namely how did the evolution of the solar system allow the formation and stable evolution of 8 large bodies orbiting the Sun. And thus, as I also emphasize, we may never be able to discern if there is actually some underlying universal purpose to the universe, although there is absolutely no scientific evidence of such purpose at this point, what is really important to understanding ourselves and our place in the universe is not trying to parse vague philosophical questions about something and nothing, but rather to try and operationally understand how our universe evolved, and what the future might bring. Progress in physics in the past century has taken us to the threshold of addressing questions we might never have thought were approachable within the domain of science. We may never fully resolve them, but the very fact that we can plausibly address them is worth celebrating. That is the purpose of my book. And it is this intellectual quest that I find so very exciting, and which I want to share more broadly, because it represents to me the very best about what it means to be human.