IS this a question for science, or philosophy, or both? Let me start the conversation with this: Given infinity, all that is possible, is inevitable. Therefore, the universe exists only because it is POSSIBLE. Infinity assures that it was inevitable. Am I wrong? Is my statement science, or philosophy? I suspect it is philosophy, given that I am not a scientist and the science guys on this forum will tear it apart. So, I suspect some are going to say there is no such thing as infinity. I would agree that there might not be such thing in the physical universe. However, it does exist, still, in the abstract. Why? Because you can't kill an abstraction. (Or can you?) However, let us assume that universes start with bang, the prevailing current theory, continue for X amount of time, which is many billions of years, if not a trillion or two, then contracts to a singularity, compresses and goes bang, once again, and we have an infinite cycle, a loop So, all that is possible has to be possible within the time frame of your average universe. But, since that is a long time, all that is possible within that time frame is still inevitable. That is why I feel the statement is true, that 'given infinity (or rather, the average duration of a universe), all that is possible, is inevitable'. However, if the loop theory is true, then I uphold the original statement. Now, the statement does not presume everything is possible; only that, given enough time, all that is possible, is inevitable. I've heard it said that with a hundred monkeys and a hundred typewriters and enough time, they will produce a Shakespearean play. No, I don't think so. That one is not possible. And is space infinite? How could it not be? Oh yes, they are saying 'space and time' are two sides of the same coin. Okay, does that change my statement? Or, perhaps the universe is circular, that if you were to head out into space in one direction, without changing direction ( according to some device that allows you to stay on a straight line) that eventually you would return to your starting point but from the opposite direction, i.e, the universe is circular. But, I don't know. Am I wrong? Am I crazy?
I find the Bouncing Universe to be likely and Time to be unlimited for all intent and purpose. You are neither wrong or crazy, right or sane...you are like everyone else not all knowing but curious. When we found out the Universe is expanding increasingly many began to speculate a "Big Freeze" or a Big Rip rather than consider that we may be in the expansion before contraction and it all takes 100 Trillion years.
Are you postulating a new unknown force that would counter the accelerating expansion that we see today?
I'd start by saying that science doesn't answer "why" questions. Science is oriented to figuring out how things work. So, at least for this science section, the questions of "how" are more appropriate, I think.
Yes, there isn't evidence of infinity. So, assuming that there is an infinity that is represented by this universe in some way is ONLY a conjecture at this point. We have the idea of what infinity is. It's useful in math. But, that doesn't mean there actually exists a physical infinity. OK, but let's remember that your assumption means that everything that follows is limited by your unsubstantiated assumptions. For example, the whole idea of a cyclic universe is not supported by any actual evidence. In fact, actual evidence would seem to indicate that it is not cyclic. And, there is no evidence that this universe is infinite in any dimension. Infinite time means that the monkeys would succeed. You argued that yourself when you said that infinite time would ensure all that is possible would happen. You ended by going back to doubt your assumptions. These are all interesting questions, obviously. But it's in the realm of theoretical physics so far. And, to be of interest one has to get REALLY serious about forming a model that leads to what we know about this universe. My own view is that a model that would answer these questions of "how" has to start with something WAY more fundamental that just string theory, or whatever. Sean Carroll and others believe the starting point has to be at the level of a wave function. From there, one has to show a progression through to answer the rest - including answers such as a resolution of quantum mechanics and Einstein gravity - a resolution that certainly does not exist today regardless of what came before - making it a difficult target!! Starting with assumptions about infinity, etc., hits me as having fun with sci fi.
But, I did make that point, though we don't have proof of it existing in the physical reality, it does exist in the abstract, You wrote 'it's useful in math', that is because math exists in the abstract, as well. True, no evidence. It was pure conjecture. But, for my limited mind, it's logical. But, that is meaningless in science, of course, No, I wrote that 'given infinity, all that is possible, is inevitable', That doesn't state that everything is possible. If it is impossible, then the monkeys will never do it. I say some things are impossible. I would be interested in knowing what they come up with. Of course, that is "IF" I can understand it. As for 'sci fi', hasn't, in some cases, yesterday's 'sci fi' become today's 'sci'?
The problem is that "the abstract" is science fiction. So, why did it show up in the science section? I don't agree. But, rather than discuss math let me just point out that math is a useful tool, NOT a definition of how the universe works. I'm pointing out that the predicate is where the problem is. And, that even the monkeys would be successful typists. I see that as true only in a totally superficial sense. Humans draw inspiration and creativity from many sources, including some sources that have NO truth at all. And, some scifi writers know a LOT about physics, so they sometimes come up with ideas that turn out to be close to reality. But, that's where the sci fi -> reality path ends. There isn't a justification for thinking that we should be looking to sci fi for descriptions of how this universe works. Maybe YOU are a writer! But, that wouldn't mean that if you wrote it, it would eventually become real - even if the universe is infinite.
This is a topic for both science and philosophy. Because we haven’t finished describing the universe yet, we need a Unified Field Theory (UFT) and consider whether the concept of the Multiverse is part of our existence. Infinity is real in mathematics. Our universe is not infinite though because it has an age and a limited size rather than being an infinite structure that has always existed. The Multiverse might be infinite and timeless though. I’m not sure where you’re going with your arguments of infinity. You’ve left me confused. As far as heading out in one direction and coming back to your point of origin, that depends on whether spacetime is flat or curved. Look up “spacetime curvature” and find the image about whether the universe is shaped flat, inward curve, or outward curve. I don’t know if they’ve decided yet which type of universe we live in. I haven’t been following this topic for a while. I also know that our visible universe is not the whole universe. There are parts of our universe where there hasn’t been a long enough time, since the creation of our universe, for light to travel from outside the visible area to reach us. Light has a limited speed.
I didn't say that math is a definition of how the universe works, However, you state that the abstract is science fiction. That doesn't ring true, to me. There is the concrete, and there is the abstract. Math is the science of abstract objects, is it not? The abstract is functionable (proof of that is mathematics, words, values affixed to or projected onto objects in space, ideas, concepts, etc.) and useful for science. Math exists in the abstract, and infinity is a function of math, therefore, infinity exists in the abstract. Why are you claiming the abstract is science fiction? I can cite numerous sources that affirm what I just wrote. I made the declaration without even researching it because it came to me empirically. But, after researching it, my research confirmed that I am correct. https://services.math.duke.edu/undergraduate/Handbook96_97/node5.html As a science of abstract objects, mathematics relies on logic rather than on observation as its standard of truth, yet employs observation, simulation, and even experimentation as means of discovering truth. So, to ask 'why does the universe exist', that, to me, is a philosophical question, which, in my view, cannot be known ( to paraphrase Kierkegaard, because life is a mystery, not to be solved, but to be lived, or something like that) . But, if I asked 'how does the universe exist', that is a question for science to solve, no? So, I should have written the title of the OP that way.
WHY the universe exists is answered in religion because we don't have a better explanation. If you have no conscious "creator" with a purpose, you have no reason for it to be. You either accept one version of the answer or the other...either it has to have some purpose or it doesn't. It just IS and that is enough. Infinity is a tricky one...if I sit in a darkened room and reflect on it I become quite uneasy. Maybe because we live in an existence with a beginning and an end. Endless to me is difficult. Finally if you talk about the shape of the universe, you have to discuss borders, otherwise you have no shape. Shapes have edges...square, cuboid, round, spherical, my question has always been "what is on the other side that defines that edge...it has to be different than what we call the universe, otherwise there is no defining edge". and ultimately we cannot know about the nature of creation until we have intelligence that can define it. We are limited by what we can know so would need infinite understanding to understand infinity...if you see what I mean.
It's SciFi that makes abstractions and presents the universe as working that way. There are problems in the field of mathematics that have been solved by techniques such as having computers iterate every possibility and test each. But, those problems are problems of math, not the physics of our universe. The investigation doesn't involve testing our natural world. We have some understanding of what infinite means, but whether it applies to our physical world in any particular way is not implied by the fact that we have that level of understanding of a definition. As you point out, math is the science of abstract objects, not the natural world. Whether the abstract objects of math pertain to the natural world is not answered by suggesting that the mathematical abstraction is known. I think your recasting of the question is an improvement, but it continues to have the problem that human investigation doesn't have the tools or data to test any proposed answer to the whole question of how this universe came into existence. I think it is important to be aware of the lines between what we know and what we don't know. There are theoretical physicists and others, who work to extend our knowledge. But, it's easy to mistake new and untestable ideas as being more than they are. We hear from some theoretical physicist that the model their team is working on might support time travel, faster than light speed travel, etc. So, we hear about how close we are to humans going to other star systems, or whatever else has excited us in scifi movies - fun stuff, but there is a line that we should learn to recognize and care about.
To me, this is the purview of religion. Attributing a purpose to the universe isn't something that physics could possibly address. Ever. How could one possibly examine the universe to detect the "purpose" of the big bang expansion or gravity or whatever? For there to be a "why" I think you would first have to decide that there is a god of some sort that has an opinion about that. Then one would have to explore what it is that this god wants.
I tend to think there is a "way" of nature and a way to live. Not so much a religion as a path to walk.
All science fiction exists in the abstract, but not all that exists in the abstract is science fiction. Still, it remains true that math is an abstraction. But, the abstract is a functionable space. There is math that is applied to the concrete, in order for man to control, manage, manipulate, and otherwise, function in the physical realm, and there is math that deals with the pure theoretical. I think they call that abstract math. However, in my view, all math is abstract, some math works in the functional space, the other in the theoretical space. Well, we haven't yet solved the big question, the 'how' of it all, though the big bang theory is the best we have, right? The 'why' of it all, that is unknowable, in my view, it's a philosophical question. I think science should go full blast on the effort to solve the problem of interstellar travel. Rockets, even things like "Ion drives' "solar sails' are too slow. Even the speed of light is too slow. Looks to me that space will have to be warped in order to conquer the great distances. We do know that it can be warped, right? But, I'm no scientist.
Something just sailed past my reading about infinity...almost all of the term infinity here so far has been about spatial infinity. I suggest that the "universe" exists in an infinity of time, given the idea of a rebounding universe. It must go on forever and forever and forever. As another thought, if the law that says matter cannot be either created or destroyed in a closed (isolated) system (Antoine Lovoisier) and Einstein said energy cannot be created or destroyed, but can only be changed from one form to another, (conservation of energy, first law of thermodynamics) , ISTM pretty sure that "creation" is eternal, and infinite in its substance since that is all there is. Unless something else outside the forces of our creation is there. Which leads me to consider that there may well be something else out there but because of the nature of our creation, we have no way of seeing it. ie the idea of different dimensions is quite possible but we will never know some if not all of them. We are locked into our world defined by our physical laws and in an "isolated" system.
I just got to thinking about how nature gets around natural laws. Take for instance the humble dandelion plant. It gets around gravity by building a flying machine ,albeit gliders. In a lawn the plant will grow shorter. Just under the lawnmower blades. In uncut areas it grows taller and placing its manufactured flying machines at a higher elevation.
I wonder about life being carried in seed and the transfer of information. Is the universe thinking? Is it aware? Could space travel be man's dandelion seed? And what about the individual? Many dandelion die, and no individual survives but the dandelion lives on. Curious.
That sounds good to me. However, that's still outside of what physics can try to answer or consider in its answers, isn't it?
Math is a very useful tool for describing relationships. Words are also a useful tool for describing relationships. But the fact that I can write a sentence in math or in words does NOT mean that the result has ANY value or is "real" in any way. Saying "infinity" doesn't mean that infinity exists as more than an abstract idea. OK. I would say the big bang is what happened AFTER this universe came into existence. And, yes, any "why" question is philosophy/religion. Well as I've mentioned before, what you ask for is engineering. Science looks for an understanding of how this universe works. Engineers use what we know to create solutions that we would like to have. I know the two get mushed together in some cases. But, theoretical physics isn't going to change its focus away from understanding how this universe works and start trying to find ways to travel fast. That really is an engineering problem. Faster than light travel would certainly require major disruption of everything we know today, especially what we have learned over the last century of physics. Everything so far shows that there IS a universal speed limit that we happen to call the speed of light - only because light is one of the "everything" that is limited by that speed limit.
I agree with that. However, I do 'believe' ( not saying's it's fact ) that the abstract is eternal, but that is a philosophical/religious proposition. Does not Einstein assert space is warped by celestial bodies? If it can be warped, then all we have to do is figure out how to warp it to travel faster than the speed of light. Yes, easier said than done, and is science fiction, but haven't some scientists posited the theory of warping space?
Spacetime is warped by mass and the accompanying gravity. Not space. Space doesn't travel. Objects and forces IN space do. You would need a bloody big "something" to warp spacetime intentionally.
