Why Is There Something, Rather Than Nothing?

A good question!

Or is it?

I’ve talked before about the issue of why the universe exists at all (1, 2), but now I’ve had the opportunity to do a relatively careful job with it, courtesy of Eleanor Knox and Alastair Wilson. They are editing an upcoming volume, the Routledge Companion to the Philosophy of Physics, and asked me to contribute a chapter on this topic. Final edits aren’t done yet, but I’ve decided to put the draft on the arxiv:

Why Is There Something, Rather Than Nothing?
Sean M. Carroll

It seems natural to ask why the universe exists at all. Modern physics suggests that the universe can exist all by itself as a self-contained system, without anything external to create or sustain it. But there might not be an absolute answer to why it exists. I argue that any attempt to account for the existence of something rather than nothing must ultimately bottom out in a set of brute facts; the universe simply is, without ultimate cause or explanation.

As you can see, my basic tack hasn’t changed: this kind of question might be the kind of thing that doesn’t have a sensible answer. In our everyday lives, it makes sense to ask “why” this or that event occurs, but such questions have answers only because they are embedded in a larger explanatory context. In particular, because the world of our everyday experience is an emergent approximation with an extremely strong arrow of time, such that we can safely associate “causes” with subsequent “effects.” The universe, considered as all of reality (i.e. let’s include the multiverse, if any), isn’t like that. The right question to ask isn’t “Why did this happen?”, but “Could this have happened in accordance with the laws of physics?” As far as the universe and our current knowledge of the laws of physics is concerned, the answer is a resounding “Yes.” The demand for something more — a reason why the universe exists at all — is a relic piece of metaphysical baggage we would be better off to discard.

This perspective gets pushback from two different sides. On the one hand we have theists, who believe that they can answer why the universe exists, and the answer is God. As we all know, this raises the question of why God exists; but aha, say the theists, that’s different, because God necessarily exists, unlike the universe which could plausibly have not. The problem with that is that nothing exists necessarily, so the move is pretty obviously a cheat. I didn’t have a lot of room in the paper to discuss this in detail (in what after all was meant as a contribution to a volume on the philosophy of physics, not the philosophy of religion), but the basic idea is there. Whether or not you want to invoke God, you will be left with certain features of reality that have to be explained by “and that’s just the way it is.” (Theism could possibly offer a better account of the nature of reality than naturalism — that’s a different question — but it doesn’t let you wiggle out of positing some brute facts about what exists.)

The other side are those scientists who think that modern physics explains why the universe exists. It doesn’t! One purported answer — “because Nothing is unstable” — was never even supposed to explain why the universe exists; it was suggested by Frank Wilczek as a way of explaining why there is more matter than antimatter. But any such line of reasoning has to start by assuming a certain set of laws of physics in the first place. Why is there even a universe that obeys those laws? This, I argue, is not a question to which science is ever going to provide a snappy and convincing answer. The right response is “that’s just the way things are.” It’s up to us as a species to cultivate the intellectual maturity to accept that some questions don’t have the kinds of answers that are designed to make us feel satisfied.

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124 Responses to Why Is There Something, Rather Than Nothing?

  1. Alex Norman says:

    While I certainly agree with your position that both “because Nothing is unstable” and theism are going to be the wrong answers, I’m not convinced that we have to bottom out in brute facts. Something like the mathematical monism of Tegmark seems to give an account of the universe as being necessary, as it’s a mathematical object, something that is necessary. What do you think about this approach, putting aside that you don’t buy his monism?

  2. Jayarava says:

    The “why” question only leads to infinite regress.

  3. Joan says:

    In my opinion, “why” is not a legitimate question. It implies the universe was “meant” to be. The only logical question starts with “How”.

  4. Berol Robinson says:

    “Why?” is a question to be directed to an archbishop, not to a mere physicist.

  5. Sean Carroll says:

    Alex– I don’t think mathematical monism helps in escaping the need for a brute fact. It is not necessary that all mathematical objects exist.

  6. john zande says:

    The question the theist has to answer is: Was there ever nothing?

  7. Patrice Ayme says:

    When theists say that the universe exists because of God, they are saying that the universe exists, because of some agent they know: that make those theists superior to us, simple miscreants, who do not happen to be acquainted with what created all. So what sounds metaphysical, by asserting “God” claims a higher place in an all too human hierarchy.

    “Universe” means literally, “turned into one”, whereas “multiverse” would be: “turned into many”. So the set of all multiverse is the universe. If we were to claim, and, or, even worse, have the feeling we know why the universe exists, we would be claiming, or have the impression, that we were God. This is not the business of physics, only the business of those who want to be guided by absolutism.

    Alexander the Great, seeing his blood flow, asked himself that question: am I a God? His Greek and Macedonian companions laughed him off. Later, on the advice of his mom, Olympia, Alexander ordered the old, most senior generalissimo Antipater, a companion of Alexander’s father, from Greece to Babylon. Antipater refused to obey. Antipater’s youngest son was Alexander’s page. Alexander found himself ceasing to be, before he could even organize his affairs.

    We are both everything and nothing relative to the universe. The key to wisdom, is to keep a balance.
    Patrice Aymé

  8. Bjarte Foshaug says:

    Of course if God himself is something rather than nothing, he is not an explanation at all, but just one more example of the thing we set out to explain in the first place. Substitute “God” for anything else we could imagine in that first sentence, and the same thing applies. From such a point of view the whole question of why there is something rather than nothing is starting to look suspiciously nonsensical. Indeed “that’s just the way it is” seems the only sensible answer.

  9. Joye Colbeck says:

    I’m not fluent enough in math to understand physics at a deep computational level, however, I agree that asking why isn’t as helpful as asking how. I rely upon physicists like yourself to keep me informed, you are always the voice of reason. Could we come up with a word other than ‘brute ‘, maybe that’s what alarms folk about these facts?

  10. Murat Turkoglu says:

    It exists to puzzle and dazzle us like a child
    in a room full of colorful toys, also to let us experience the coldness of existence.

  11. Wilhelmus de Wilde says:

    You could eventually replace God with Consciousness. In my model of “Foundational Quantum Loops (FQRL) ALL, probable universes are emerging (graphically represented as loops) from the After Planck Area (that can be reached at each point of a reality) where time and space do not exist, so each event is simultaneous. In this Total Simultaneity resides Total Consciousness. When there is no consciousness there is no awareness and everything is useless. In order for completeness Total Consciousness is letting emerging all probable realities. Read more in my FQXi contest participation:.https://fqxi.org/community/forum/topic/3008
    this approach gives also a resolution for the MWI.

  12. Adel Sadeq says:

    Hi Sean,
    It is a shame that your FQXI essay has been neglected. Maybe some participation from your side would help. I think your essay is excellent and maybe you don’t realize it but its very close to mine although on the surface it might not look that way. And mine says and proves that the universe is a very simple mathematical structure, so I believe you are saying the same thing without realizing it, I understand though that your first reaction is to disagree since it goes against your present blog theme. Here is a little write up that gives an example when the why and the how match.

    “Now suppose I ask you to tell me what will happen to some “object”, but I don’t tell you anything about it (how fundamental can you get) !! like what mass it has or what it will do if another thing is present. Ok, I’ll give it a try. First I will say I will “invent” a coordinate (actually that is not needed) and since I don’t know where it exists I will restrict it to be in some range and eventually make that range variable. If we add another one next to it with similar setup and at some distance that can also be varied. Now, we can calculate all relative information just like our original idea in the essay.

    Both situations reached the same conclusion with generalization leading to all of physics QM, QFT, Gravity like shown. In one instance we acted like GOD and decided to design a dynamic universe, in the other we are ignorant humans but figured out how things should work, and both match and are the FUNDAMENTAL building block.”


  13. Cecilia Biegel says:

    Why there is something rather than nothing seems less fundamental to me, than asking why are we aware of the universe at all. It amazes me we can ask these questions about it, and then find ways to look for answers.

  14. Bunsen Burner says:

    I don’t see why this question needs to be so broad as to bring in metaphysical concerns about the nature of physical laws and so on. It would be enough if physics could demonstrate that the physically relevant stuff like spacetime, matter, energy has to exists. I know Vilenkin wrote a lot of papers in the 1980s where he tried to model an operational state of physical nothingness, and showed that tunnelling probabilities from this state were finite. The maths looked a bit dodgy at times but I always viewed the comment ‘Nothing is unstable’ in this light. Not that there way a prior state of Nothing from which the universe sprang, but that it’s not a state possible at all.

  15. Katrin Boeke-Purkis says:

    Something came into ontological existence when apperception was born into the Cosmos. Without apperception there would be nothing to perceive the something….

  16. Perhaps it would be more mature to simply concede that there are limits to our current understanding — and leave the question open for future generations to consider.

  17. Swami says:

    Using the word why tends to lead to metaphysical speculation. Since we can’t step outside the universe, perhaps we should be content to just ask how the universe works.

  18. Brent Meeker says:

    As the late Norm Levitt put it, “What is there? Everything. So what isn’t there? Nothing.”

  19. Adel Sadeq says:

    Hi Sean,
    Reading your posted paper in this thread I see that you bring up alpha. I was thinking to entice you to read my paper I will make this quick move.
    from my theory(idea whatever) I deduce the following

    1/alpha= 137.03599901

    (M_p/M_e) =(3^3/2)*(1/alpha-1) -1/3 =1836.15265

  20. Dan Hawkley says:

    This question can be answered mathematically in terms of predictions and observations. For example, the idea that “energy” cannot be “destroyed” amounts to an experimental logic (repeated any number of times, given prediction B remains false):

    (prediction Alice at point Alice): everything (including point Alice) will not be annihilated;
    (prediction B at point B): everything (including point Bob) will be annihilated;
    (observation AB as distance AB): everything (including opposite directions) was not annihilated:

  21. “Why is there something rather than nothing” is what I would call a question for another eon. Or many, many eons… Much bigger fish to fry right now. “Terraform Earth First!” I always say.

  22. Brad Jackson says:

    I don’t know why this question gets posed. It is not answerable by science or religion. It is a philosophic question with no real answer other than a personal belief system. This goes for theists as well as physicists. I see the universe as having intelligence behind it because life seems to be a way of expressing its ability to recognize itself. Not just through the arrogance of our eyes but though every organism that perpetuates life at any level and allows information to propagate. In the natural universe I see different aspects of how we interpret what we see, patterns of repeating forms and deeper codes as in DNA. It all depends on how you conceptualize God. Take the religion out of it and I see intent. Say what you will but this gives me hope even if I’m wrong.

  23. Bruce says:

    This “why” question can be restated as a “how” question which is equally impossible to answer. In the words of R. C. Sproul, “If there was ever a time when there was truly nothing, there could never be anything.” The fundamental question for naturalistic science is, “How did the universe create itself out of nothing?” The claim that it just happened (i.e., by natural processes) is a statement of faith, not science. All that you have done is substitute a supernatural, intelligent Creator with a natural, unintelligent one.

  24. Bill hicks says:

    The mind is all..the universe is mental.

  25. joel rice says:

    ‘something’ is too wishy washy. Imagine that there is some mathematical structure which actually enumerates particles
    rather than just accommodating 3 generations of fermions – ie , it would be an explanation.
    The point being – we do not have any such idea, so we are not quite sure what ‘exists’ in the first place.

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