|
Post by abacus9900 on Oct 6, 2010 21:25:20 GMT 1
The problem here is that physical reality is not the same as maths, therefore, you cannot just assume that the universe, in whatever state, can be endlessly regressed. If you attempt to do this you will inevitably arrive at a point where you are considering 'point particles' which cannot be further subdivided. This is where the idea of an infinite universe meets an insurmountable paradox, something STA should be aware of but apparently has forgotten about.
Having said that, STA has still failed to define what she means by 'infinite.'
I think it's worth noting here that mathematics, despite providing science with a powerful tool, is just a tool and should not be pushed too far. Our ideas about the universe do not necessarily correspond exactly with reality.
|
|
|
Post by typobrane on Oct 6, 2010 23:19:58 GMT 1
I have an understanding of infinity and infinities but have no concept of a nothing Well typobra, I am surprised at this inversion of normal 'perceptions' I do not think I am normal so no surprise at your surprise.
|
|
|
Post by typobrane on Oct 6, 2010 23:28:24 GMT 1
I have an understanding of infinity and infinities but have no concept of a nothing Well typobra, I am surprised at this inversion of normal 'perceptions' For example most people have direct experience of having nothing in the bank, no-one has any experience of having an infinite number of pounds in the bank; '0' is quite manageable in mathematics, in physics, in economics, in poltics, well, in just about everything really, whereas infinity is not manageable in any field (to my knowledge) They are examples of nothing in something and not nothing in nothing. For something to come from nothing then nothing must have something.
|
|
|
Post by mak2 on Oct 7, 2010 9:59:39 GMT 1
This is true enough. If you run time back-wards in the mathematical model, you eventually get close to the singularity. Conditions there are so different from anything we know about that the model is no longer reliable. However, I do not see how this prevents the universe from being infinite and expanding. The model is OK for the universe as it is today.
|
|
|
Post by abacus9900 on Oct 7, 2010 10:23:34 GMT 1
To be perfectly honest, I wonder why people use the idea of infinity as it doesn't seem helpful because it is basically undefinable and can never be tested since it never ends!
|
|
|
Post by speakertoanimals on Oct 7, 2010 16:46:39 GMT 1
As usual, you are totally confusing two different things, the question as to whether the entire universe is or is not infinite, and the question as to whether or not matter in a universe can be compressed infinitely. They are totally different questions.
What's the problem with point particles? The standard model of particle physics says that basic particles (such as electrons) ARE point particles, that is, they have no internal structure. String theory says otherwise, in that it says they are little pieces of string, rather than points.
I think what you were confusing it with was the question as to whether space and time are infinitely divisible, whether space is continuous on the smallest scales, or whether it is discrete, so that there is some smallest possible distance, and some smallest possible unit of time. But this is a totally different question as to whether the universe is infinite or finite in spatial extent.
The problem isn't the maths, you can represent either case mathematically, so it's just a simple question of physics -- should we use maths of continuous or discrete space and time. It's not a fundamental problem with using maths to write down physics, as you seem to want to claim. And since at the classical level, we have no evidence that space is anything other than continuous, that is why we use continuous spacetime in relativity.
At the quantum level, we may have to use a discrete model, but then that is different in that we would be talking about quantum gravity, rather than the classical theory of gravity that is relativity. There are various suggestions as to how we go from a classical, continuous theory, to a quantum discrete one, but until we have more study and more evidence, the question is still open.
If you still don't know what infinity is (and it certainly looks as if you don't), I say again, go look it up!
|
|
|
Post by abacus9900 on Oct 7, 2010 20:20:31 GMT 1
Nobody 'knows' what infinity is because it is not measurable and therefore not testable. Infinity is more of a philosophical, even religious, idea than a scientific one. You cannot assume that mathematics will always correspond to states of matter that probably do not conform to our, hitherto, limited scientific definitions, such, for example as spacetime. Relativistic mathematics inside the center of a black hole, for example, simply break down.
As to the universe being infinite - this is a philosophical consideration and actually, seems a quite pointless one.
|
|
|
Post by mak2 on Oct 7, 2010 20:58:26 GMT 1
Anyone who proposes a model of the universe, is certain to be asked the question "What happens if you set off in one direction and just keep going?" Either you encounter some kind of barrier ( seems fairly unlikely) or you go around and arrive back in the same region you started from or you can keep on going forever. The last alternative, is not a bad definition of infinity.
Or you can use a mathematical definition, limit(1/x) as x tends to zero. Start with a positive value of x and imagine it becoming smaller and smaller but never quite reaching zero.
Or, as you suggest, we can forget about infinity and do something boring and useful.
|
|
|
Post by abacus9900 on Oct 7, 2010 21:26:03 GMT 1
mak2, what happens when we die? Do we continue to experience time or simply rest in oblivion? If the latter then oblivion is a valid concept where time and infinity have no meaning. I suppose what I am leading up to is this: is infinity a function of consciousness? Remember what Descartes said? "I think, therefore, I am." In other words, any idea at all, including infinity, maths, the universe, etc. is simply a function of being alive. A more outrageous question: is reality itself a function of being alive? To paraphrase Descartes: "I think, therefore I and everything else exists."
|
|
|
Post by speakertoanimals on Oct 8, 2010 12:45:33 GMT 1
I think, therefore abacus is a figment of my imagination, and I'm buggered if I know why I'm such a masochist.................
When in doubt, as we might have suspected, abacus just resorts to the usual puerile pseudo-philosophical nonsense.
|
|
|
Post by abacus9900 on Oct 8, 2010 13:16:49 GMT 1
Allow me to ask you a question, STA.
Can a dead person experience reality?
|
|
|
Post by mightydrunken on Oct 8, 2010 16:01:16 GMT 1
Allow me to ask you a question, STA. Can a dead person experience reality? I think Abacus has taken mak2 suggestion of, "Or, as you suggest, we can forget about infinity and do something boring and useful useless." ;D
|
|
|
Post by mak2 on Oct 8, 2010 16:22:54 GMT 1
In his latest book, Stephen Hawking mentions the idea of Model-Dependent Realism.
"..our brains interpret the input from our sensory organs by making a model of the world. When such a model is successful at explaining events, we tend to attribute to it....the quality of reality..."
He does not say whether a dead person can experience reality but, judging from the content of the book, I think he would be sceptical. However, if one person dies, others will attribute reality to their models of the world, some of which will be very similar.
|
|
|
Post by abacus9900 on Oct 8, 2010 19:10:52 GMT 1
Allow me to ask you a question, STA. Can a dead person experience reality? I think Abacus has taken mak2 suggestion of, "Or, as you suggest, we can forget about infinity and do something boring and useful useless." ;D Notice you haven't tried to deal with the question I posed to STA. Wonder why?
|
|
|
Post by abacus9900 on Oct 8, 2010 19:13:07 GMT 1
What about the situation where there existed absolutely no life at all in the universe?
|
|