From several theists in several threads has come the insinuation or outright charge that basic cosmology contains numerous inconsistencies (or, in one case, proves the existence of the supernatural!).
Now, I Am Not A Cosmologist but I understand the basics well enough to defend them from such charges. Here are some hopefully educational statements. Cosmologically speaking:[ul][li]There is no such thing as “outside the universe”. This is a much stronger statement than “there is nothing outside the universe”. The universe is space. Space is the universe.[/li][li]There is no such thing as “before the universe”. The universe is time. The universe has existed for all time past, and will exist for all time in future: One may as well say that the universe exists for all time.[/li][li]There has never been no universe. There is no such thing as “no universe”. The universe did not come from anywhere, nor did it appear, nor was it caused, nor did it ever have a potential to exist. There was no “something-from-nothing event”. It exists over all time. It has always existed.[/ul]Some further points concerning the Big Bang:[ul] “Big Bang” was a term coined originally to ridicule the idea of an expanding universe. It is misleading in that it implies an event rather than simply a “place”. Perhaps a better term is timeless singularity. [/li][li]If we travel “back through time” we come to a point where our normal laws of the universe break down (the Planck epoch). We find that as we go back we reach a point where “time” has less and less meaning, essentially “becoming” another dimension of space. The point at which this “occurs” is the timeless singularity.[/li][li]The timeless singularity did not have a “cause”, and it is an “origin” only in the strict mathematical sense: It simply exists. Now, what shall we call this system comprising a timeless singularity to which is attached a “line of time”? Let us call it the Universe.[/li][li]Our universe is the place in the Universe where time exists.[/li][li]That’s so important it needs repeating: Our universe is the place in the Universe where time (or, at least, the illusion of time) exists.[/li][li]Our universe is also the place in the Universe where fundamental constants have the values they do. Consider the timeless singularity as a “map” of universes, each with different constants, with a “line of time” attached to “ours”. (We could play all kinds of “geometrical analogy” games here - I’m keeping it as simple as possible.)[/ul]Finally, to (tentatively!) answer in advance some of the questions which are bound to arise (although, I hope, do not form the entire focus of this thread):[ul]Our universe may be one of many places in the Universe where time exists. These other lines may also join to the timeless singularity. They may also have different fundamental constants, in which case asking “why is our universe, Goldilocks-style, just right for life?” or “why is our universe not different?” is like asking “why don’t I live in Libya?”.[/li][li]Why is there not nothing, no Universe? Trickiest to answer of all. One could simply point out the tautology that the nonexistent universe does not exist, but I believe there might be “better” answers. One that I liked (although admittedly I have little grounding in self-referential set theory) was this: the Universe must contain the set of universes. It might be that the Universe contains an infinite set of universes. A truly infinite set must contain the empty set: the “nothing” set. Thus “nothing” is a member of the infinite set of universes.[/li][li]Are these scientific theories? It is entirely possible that these hypotheses are completely untestable, in which case no. However, if their mathematical constructs are consistent, we might find some consequences which are detectable in our universe, which would at least give us some confidence beyond mere faith and maths alone.[/ul][/li]This third list was presented purely for completeness’ sake - I would prefer to focus on the first two lists before moving onto the “really hard questions”. Also, there are of course all kinds of proposed models of the singularity but I would hope that we do not become mired in the details of any particular idea (I understand that the “quantum foam” option as advocated by John Wheeler has currency amongst some of you here).
So, the timeless singularity exists, and our universe exists for all time: The Universe in a coconut shell. I await your metaphorical rain of balls.
Just to help me get things straight: The spatial dimensions (forgetting time for the moment) are properties of the universe, as opposed to the backdrop in which the universe exists? Any offical word on this?
Not being a cosmologist, I can’t debate the finer points of the first two lists. I essentially understand the basics of the points presented and I agree that they provide a satisfactory explanation of our “observable” universe.
Essentially, to grasp the basic ideas all you need to do is imagine a universe with one less spatial dimension (2), and add a third dimension representing time. Anyone that has the imagination to perform this mental “trick” will be able to grasp the gist of the concepts presented in both lists.
Having said that, I must admit that it gets much tougher from there on. I’ve never been able to fully digest Relativity for example. Also, having read “The Universe in a Nutshell”, (which reads like a bedtime story for genius kids), I wasn’t able to grasp the concept of “imaginary time” put forth by Hawkings.
Anybody understand what he means by it? Care to explain it to me?
I’ve always thought of it this way,
The Universe (capital U) had to “choose” between three options:
Do nothing. Absolutely nothing. Why bother?
Configure itself in some arbitrary way, over many possible ones.
Exist in each and every way. Every conceivable posibility exists.
Number 1) seems like the way to go for a lazy Universe, but obviously, “it” did not “choose” that option. Also, the concept that the universe must make an “effort” to produce “something” is just a human conception. It’s all mathematics anyway. No effort to exist at all.
Number 2) seems to me too … er … arbitrary.
Number 3) is very appealing to me. If you think about it, it just might be the easiest, most generic way to go. Even number 1) , an empty unverse, is a version of number 2), an arbitrary configuration.
The fact that we observe THIS particular version of the universe might be related to the Anthropic principle. Intelligent creatures smart enough to pose these questions will live in very particular universes which allow their existence.
“Imaginary time” is merely a transformation which allows us to treat time much like just another dimension of space, in the same way that imaginary numbers allow us to treat the roots of a negative square much like just another number. (The distances in those Minowski space diagrams get a bit tricky with all these -t factors running around.)
In the same way that imaginary numbers have real, actual use in everyday engineering, so imaginary time has real use in cosmology (although it still doesn’t seem able to provide unique initial conditions!).
This makes it all crystal clear, I’m sure you’ll agree.
Well said, Sentient. I don’t see anything to debate. In fact, I’m considering just linking to this thread in the future rather than having to explain it over and over, from square one each time.
The same disingenuous question seems to come up in virtually every religious or cosmological debate here: “What caused the Big Bang?”. It gets downright tiring having to re-explain it every time.
I can remember back 25 years or so when I was first introduced to these ideas. I really had a hard time grasping it. Time is such an important concept to us in our day-to-day lives that you really have to let go of a lot of assumptions to really “get” it.
To make it more intuitive, try thinking of time as simply another dimension, just like height, width, and depth. Now, imagine you are standing in your living room, and you can’t see your kitchen right now. Is the kitchen still there? Of course it is, but you aren’t in the kitchen right now. It exists, it’s part of your house but you aren’t there. You’re in another part of the house.
Now, just expand this to include time as another dimension, the difference being that it’s a dimension where, for whatever reason, we cannot move freely from one point to another. Right now, we are in the year 2003. The Big Bang exists, but it’s at the other end of the time continuum, and we aren’t there right now. Just as your kitchen exists when you are standing in the living room, the Big Bang exists when we are in the year 2003. The difference is that we can only move in one direction. It’s kind of like The Haunted Mansion at Disneyland - you can only start at one end of the building and move through all the rooms. The place you started at is still there, but you can’t go back.
Here’s another way of looking at it:
If you look at the Pythagorean Theorem, you’ll see that when getting total distance from two different dimensions, you deal with squares: you square the distance in one dimension, then you square the distance in the other, and when you add them you don’t get the total distance, but the total distance squared. In relativity, things get a little weirder. Instead of adding stuff together, you subtract the spatial dimensions from the temporal one. So distance squared is negative time squared. If you try to relate (unsquared) distance to (unsquared) time, pretty much the only way to do it is to think of distance as being imaginary time.
So you’re saying that if we want to see what the big bang was like, we’ll have to stand in line for a really long time?
(Is the universe an E-ticket ride?)
blowero close, but… - time is the one dimension with a “minus sign” to describe it mathematically. That’s true even in modern super string theories that deal with up to ten macroscopic spatial dimensions. Time is another dimension, true, but not an ordinary one.
Yet, there are models that include the possibility of a second dimension of time (thus making it possible to gain more freedom of movement in time) - but those models are considered as exotic (even by mathematicians).
You think this is really a stronger statement? One is definitional, the other has the form of a proposition. I guess it is a matter of preference, but I would consider propositions to be stronger than definitions.
In fact, this is largely the sense I get from your OP: defining terms. Your second note in the first group (the universe is time) is really just extending the definition. The third point is the strong one that says, “The thing I have just defined, ‘the universe’, exists.” We could then say that because time is a part of the definition, there is no meaningful way to describe events without it.
Sure, it is ok. How about the unmoved mover? What advantage does one have over the other?
As I assume many theists get tired of having to explain why God is uncaused.
The outline is valid. If we accept the definitions in the OP as true then science is sound, a real plus for realists. Still, metaphysically arbitrary IMO.
“timeless singularity” and “unmoved mover” do not describe the same thing. The latter implies a creator of some sort. It’s not a question of “advantage”; it’s that they are not interchangeable concepts.
It’s not arbitrary at all. The theory is based on empirical observation and mathematics. And we know that time is not immutable. It has been proven by flying atomic clocks around in jet planes at high speed. This is not a matter of arbitrarily accepting one explanation over another.
All of which is really beside the point, because the problem comes when theists attempt to take one aspect of the theory, namely the Big Bang, and then ignore the rest of the theory, and ask what came “before” the Big Bang. You can’t prove something scientifically by arbitrarily using only the elements of science that help your point, while ignoring the rest. The definition of the Big Bang is that it’s the point in the universe where matter is infinitely dense and time is undefined. You can’t have a “before” the Big Bang by the very definition of what it is. It would be like going to a car dealer and saying “I want to buy a blue car that is red.”
In a sense, no chain of causality can be followed past the Big Bang (assuming that it truly occurred, was actually a singularity, and that our ideas about what a singularity is are accurate). Any information contained in a hypothetical “previous universe” would have been wiped out – there’d be no sense in which it would be meaningful to say that those events had ever happened.
As far as we’re concerned, that would be the beginning of everything.