I understand that physics works based on very elegantly and intuitively developed mathematical theory, and we are still in the process of figuring out a complete, unified theory: but I have noticed a lot of people who study or work on physics that adamantly refuse to even consider the question of what could have happened before the Big Bang, i.e., what could be the real origin of the universe.

Their first answer usually is "Big Bang created space-time, it's idiotic to even consider the notion "before the Big Bang". While this is completely true, it feels like just brushing the real question under the rug. At the end of the day, is the role of physics not to figure out the ultimate truth, and what could be the reason for people trashing this question completely? It feels like the modern day equivalent of saying "The Earth is the center of the universe, and it is silly to even consider something else could be the center".

closed as off-topic by Keelan, virmaior Dec 18 '15 at 12:44

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    I'm voting to close this question as off-topic because it seems to be about the interests of the physics community community - the philosophical problem is unclear. – Keelan Dec 18 '15 at 8:22
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    If the question is "why do physicists not think much about metaphysics?" it's because these two things are different and their training is in one and not the other. – James Kingsbery Dec 18 '15 at 13:52
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    @jobermark how is this a metaphysics question? It asks us why a certain group thinks in a certain way? Is that what metaphysics means? – virmaior Dec 19 '15 at 0:00
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    Well, in this case, I just see at is precisely the methodological boundary where most physicists would think they're not doing physics since the laws of physics start with a/the big bang, so I'm not quite sure how to extend it non-circularly. – virmaior Dec 19 '15 at 17:06
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    Do you also object to geometers who refuse even to think about the properties of three-sided squares? – WillO Dec 21 '15 at 4:55

Physicist Lee Smolin, among others, has theorized about what happened before the Big Bang. He also provides are reason for why physicists usually refuse to talk about it. Anything theory about what happened before the Big Bang is not falsifiable, and so it is something that science cannot talk about.

It is possible, that at some point in the future our knowledge of math and physics will change to the point where we can make testable and falsifiable statements about what happened "before" the big bang (at least causality wise). I personally am hopeful about that. Consider for example the fact that atomic theory seemed completely untestable back in the time of Democritus, but it is now. Maybe something analogous will happen in cosmology.

Note (although I doubt that this is what you are looking for) that proponents of some religions consider faith to be the proper method of inquiry about what happened before the big bang. This is one of the reasons some physicists dislike speculation of the type Smolin engages in, they feel that they will wonder out of science and into mythological and religious territory.

  • Re. "anything before BB is not falsifiable." Sir Roger Penrose's work appears to contradict that: "clear concentric circles within the [cosmic background radiation] data, which was collected by NASA’s WMAP satellite over the course of a seven year period ... To him, these posits are spherical evidence of the gravitational waves, massive ripples in spacetime that are created through the collision of massive black holes, which took place during the previous aeon." ref: Evidence For ‘Conformal Cyclic Cosmology’ (CCC) – Chris Degnen Dec 18 '15 at 11:26

The reason, I would assume, is because it's highly speculative. Nevertheless more physicists are talking about cyclical big bangs and multiverses (new universes in black holes), etc.

A credible lecture video on the cyclic universe theory is Sir Roger Penrose's "Aeons before the Big Bang", also summarised on this page: Alternate Theory of the Big Bang.


Your question touches several issues:

1) Physics cannot "figure out the ultimate truth":

We do not know whether an ultimate truth exists. One can even doubt that the concept of an ultimate truth is a meaningful concept. Physics advances step by step, without knowing whether these steps lead to the top of the pyramid or the terrain gets wider and wider with every step. New results prompt new questions.

Secondly, physical theories are always hypotheses, one cannot prove general physical theories. Notably, scientific hypotheses can be confirmed or refuted, but not proved.

2) Currently, mainly two different opinions exist about the Big Bang. One group states as you write: "Big Bang created space-time, it's idiotic to even consider the notion 'before the Big Bang'". They are right as long as they work within the standard model of cosmology where extrapolation back in time leads to the distinguished limit point of Big Bang.

Another group investigates a cyclic universe by applying methods of quantum gravity to cosmology. Here Big Bang does not exist as a singularity. See Bojowald, Martin: Once Before Time: A Whole Story of the Universe (2010)

3) Probably you are not satisfied with these answers. But presently, physics has to leave open the decision between the two models.

And until now, physics had always to leave open certain questions. I doubt whether physics will find a final theory which satisfies every need articulated by metaphysics.

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