Here is one to wrap your minds around. If the universe is infinite and life exists on this planet it stands to reason that there is a chance that it exists elsewhere. Taking that chance what ever it happens to be (let’s say 1 in 100,000,000,000) and applying it across an infinite universe; life therefore HAS to exist elsewhere. Now if I imagine a planet populated by super intelligent sheep knowing that sheep exist here and there is that chance that they exist elsewhere…(you can see where this is going don’t you. Well to finish it off: If the universe is infinite does anything I imagine therefore exist no matter how absurd?
If the universe were infinite (which I do not believe it is), it would still be subject to its own laws.
Certainly you can imagine things that are impossible (say a brain of a certain size is required for intelligence: an intelligent worm might be impossible; I don’t know about a sheep).
Regarding those things you believe that are actually possible, it is still not an open and shut case. The universe could be infinite but without much variety. This is sort of like the question about whether any arbitrary pattern of digits can be found in the decimal expansion of Pi: we just don’t know.
Now we’re getting somewhere. Yes, anything and everything that has ever been thought has definitely existed IF you agree that thought itself is a realm of reality. But, that doesn’t necessarily mean that the smart sheep planet exists in the physical world. I believe that reality is indeed subjective. So if I see Elvis in a flying saucer and really believe that(my emotions will reinforce the belief with physiological responses), then for ME it was real. But no amount of ranting on my part will make it true for your reality(or the physical world).
I assume that when I die, the hallucination dies with me. Unless we carry our delusions into the next plane of existence…
> Well to finish it off: If the universe is infinite does anything I imagine therefore exist no matter how absurd?
First, the universe isn’t infinite, it’s just really big. Second, even if it was infinite, that doens’t imply that anything you can imagine must exist.
k0myers
This reminds me of the old fallacy that a thousand monkeys at a thousand typewriters will eventually hammer out Hamlet. Even given an infinite number of monkeys, I don’t think it would ever happen. This is because (and I’m quite sure I’ll be corrected if I’m wrong) of entropy, or chaos theory. Simply put, the universe does not tend toward any kind of pattern or organization, it tends towards chaos and homogenization. Not only that, but even if the universe were infinite (which I don’t think it is), I don’t think there would be any guarantee that any and all possibilities of all things exist somewhere, somehow. Rather than trying to think of why it wouldn’t be, I can’t think of any reason that it would.
Oh well, my two cents anyway.
Eclipsee writes,
“Even given an infinite number of monkeys, I don’t think it would ever happen. This is because (and I’m quite sure I’ll be corrected if I’m wrong) of entropy, or chaos theory.”
Ok, consider yourself corrected :-). Neither entropy nor chaos theory have anything to do with it. The premise was that the monkies type randomly, in which case an infinite number of monkies for a finite time, or a finite number of monkies for an infinite time, will eventually produce hamlet. Nobody is saying you can actually obtain an infinite number of monkies, just that if you could, and they typed randomly, you’d get hamlet out of them.
k0myers
Now I don’t believe that being able to download Hamlet off the Internet proves the monkey thing.
I’ll not monkey with the Hamlet question, but is the chaos theory generally accepted?
If so, how would an organism come to be?
TennHippie writes, “I’ll not monkey with the Hamlet question…”
Har har 
And carries on, somewhat less pun-ishingly: “but is the chaos theory generally accepted? If so, how would an organism come to be?”
Yes, chaos theory is generally accepted; there are examples of such systems, so think of it as an existence proof. The theory basically says that for some types of systems, small variations in the initial conditions can bring about large variations in the future conditions, in a manner that is difficult to predict. But the way you phrase the question leads me to think that you see this as rendering life less probable? On what basis? I don’t see the connection. If anything, I would think the opposite, that a chaotic system would be far more likely to have life arise in it, due to the potential for wide variation in conditions. A static or near-static system isn’t too interesting when the goal is to randomly stumble upon something that can reproduce itself.
Many people also try to use entropy to prove that life “can’t arise from nothing”, but this betrays a total misunderstanding of what that theory says, which is that entropy in a closed system increases or remains the same. Nowhere does the theory prevent local (such as on a planet), decreases of entropy. Planets are not closed systems; they tend to have rather large energy inputs. The universe is teeming with examples of local decreases in entropy.
k0myers
If the Universe is infinite, does anything we imagine exist?
Hmmm…that all depends.
If the wave function of the Universe collapses, then no, this “reality as we know it” is pretty much all that there is. Every possibility that didn’t become reality will be as if it never existed.
If the waveform of the Universe does not collapse, then yes, anything at all is indeed possible. Possibilities will all be reality in some world (ever watch Sliders?)
Consider the words of Jorge Luis Borges:
No, remember that infinite size does not mean infinite variation. For instance, we might have infinite space, but limited matter.
>>while contemplating the navel of the universe, I wondered, is it an innie or outie?<<
—The dragon observes
To repeat what k0myers has already stated: first, the universe is not infinite; second, even if it were infinite, this would not make everything imaginable exist.
The simple counterargument is the point jens brings up, which is that certain things we can imagine are impossible. For instance, I can imagine a species identical to humans, which live on the surface of a sun. The properties of the universe make this completely impossible, which means the probability of its occurrence is zero; it will never ever happen, even given infinite opportunity.
If you change the question, and ask whether everything possible must eventually exist in an infinite universe, the answer is less clear. I think this must be a “yes”, if only because of the mathematics. (Small probability * infinity = 100% probability)
Jens writes, “say a brain of a certain size is required for intelligence…”
It may be required, but as the existence of Pauly Shore demonstrates, it by no means guarantees that result
k0myers
Slightly off-topic:
In the Hitchhiker’s Guide to the Galaxy, it was surmized that since the universe was infinitely large but that the number of life forms was necessarily finite, the average population of the universe is zero. 
OK I am somewhat befuddled on a couple of points here… First: IF the universe is infinite how can there be a finite amount of matter is one not dependent on the other?? And second How can any one prove the size of the universe? I realize we are dealing in abstracts here but how can one sat for sue that the universe is finite (and if it is what the heck does it look like? (Is it the doughnut shape that we all know and love?)) My point is in the original phrasing of the question IF being the key word but I suppose is I had wings growing out of my butt I could learn to fly too
OK I am somewhat befuddled on a couple of points here… First: IF the universe is infinite how can there be a finite amount of matter is one not dependent on the other?? And second How can any one prove the size of the universe? I realize we are dealing in abstracts here but how can one say for sue that the universe is finite (and if it is what the heck does it look like? (Is it the doughnut shape that we all know and love?)) My point is in the original phrasing of the question IF being the key word, but I suppose is IF had wings growing out of my butt I could learn to fly too
Has anyone else read Heinlein’s “Number of the Beast”? I’m not much on higher mathematics or multi-dimensional space, but Heinlein came up with the charming notion that there are three time axes as well as three spacial axes, and that because of this, there was an indenumerable number of possible universes.
The heroes ended up exploring Rice-Burroughs’ Mars, Baum’s Oz, Carroll’s Wonderland and a few other universes made possible by a not-quite-infinte variety of universes. Heinlein uses the theme in his multiverse several different times.
Of course, it’s fiction, but a delightful idea nonetheless.
“Knowing others is wisdom. Knowing yourself is enlightenment.” - Lao-tzu, Chinese philosopher
Does anything we imagine exist?
I imagine a being who has the capacity to imagine something that does not exist.
Either the being that I imagine does not exist, or else the being I imagine does exist, but can imagine something that does not exist.
Conclusion: Not everything we can imagine exists.
Easy.
>If the wave function of the Universe >collapses, then no, this “reality as we >know it” is pretty much all that there is. >Every possibility that didn’t become >reality will be as if it never existed.
Ah, but the wave function won’t colapse until it state is tested by an external observer? So anything (and everything) goes up until the point God peeks in the box. Then he will know what existed and what didnt.
[Insert Clever Quote Here]
Ahhh…but who will peek into the box to see a fully informed God?