That it could happen and doesn't is because of the Second Law of Thermodynamics, that the entropy or disorder of the Universe is always increasing.A distant galaxy is only able to continue existing to the degree that other objects in the Universe, including myself, are prevented from transforming into a force capable of destroying it. It does not really matter that I will probably never change into such a force. All this means is that the causal circumstances will probably never be ripe for me to undergo such a transformation
Physicists use the concept of phase space to make probablistic arguments. Every particle in the Universe at any given time has three position coordinates and three momentum coordinates, given an arbitrary choice of a coordinate system (where the "0's" are in the six dimensional space we construct.) Physicists believe that at the beginning of the Universe, all particles were in an extremely ordered state, densely packed together, and that if even one of the particles had been in a diffrent state, the Universe as we know it would be entirely different. This accords with David's assertion that everything is somehow connected.
In fact, following an argument I borrowed from Roger Penrose, physicists are able to estimate just how unlikely this highly ordered state of the early Universe would be if it occurred purely at random. (Of course, by this reasoning, any initial state would be equally as unlikely). The chances that the original state happened purely randomly are one in 10 x exp [10 x exp (123)]. You could not write this number out in regular notation, since if you could write down a "1" and attached a zero to every particle in the Universe, you wouldn't have enough particles for all the zeros that would have to follow the "1".
My point here is that the initial state of the Universe was extremely ordered, but not perfectly so, or else it would be uniform - homogenous - today, and it clearly is not. This is assuming - and just about all physicists do assume this - the Universe proceeds in a direction of increasing entropy from any given moment to the next. By this I mean the Universe as a whole. To envision this more clearly, phase-space diagrams are helpful. Here is a link to The Large, the Small and the Human Mind by Roger Penrose at Amazon.com if you are interested. This book covers these ideas very succinctly with clear diagrams, if anyone is interested.
Where I have trouble agreeing with David is here:
It is very possible, but there is nothing to argue that it is even remotely likely. In that respect, it is nothing like a house of cards, because if you chose a card at random to remove from any such house of cards, the chances are the house will crumble. Let me rephrase that slightly: the chances are much greater the house would fall than the chances of our dust speck's having been somewhere else would mean the entire Universe would somehow be unrecognizable.The dust-particle in a different position would have an entirely different causal web in support of it, which means that the effects of this web would be entirely different. It is very possible that the none of us would be here, that the human race would never have evolved, that the stars and planets would have evolved very differently, and so on. It is indeed very much like a stack of cards.
Given the topic of our thread, I submit the hypothesized highly ordered state of the very early Universe as evidence that a Creator or Designer is or was involved, and again, I know this is not proof but I'm still going for that preponderance that Kevin challenged me to produce.