hey hey hey...found a contradiction to that too!
Abhishek, u were trying to explain entropy on the basis of probability. But this can be done just as long as you do not do it on cosmological scales. Let me give u an example to explain my point...
Suppose there are three molecules inside a room of initial volume Vi. Let the vol of the three molecules together be Vm
=> prob of finding a molecule initially P(i) = Vm/Vi
Now suppose the room expands to a volume of Vf.
now, the prob of finding a molecule P(f) is Vm/Vf
Since P(f) < P(i), entropy has increased.
But the important point here is that the volume of the room has increased because more space has been occupied.
However, this is not the same with universe. In the expansion of the universe, space itself is expanding!! So there is no question of more space coming inside its boundaries! That means the probability will always remain the same!
Another analogy to explain this point...
Consider a balloon to be the universe. When deflated, u mark a grid on it such that there are, say, 10 squares on its surface. Now suppose there was a hole in the balloon of area A square units.
Initially, the prob of finding the hole will be A/10.
If the balloon were inflated, the probability would still be A/10 because there are still 10 squares on the balloon surface and the area of the hole still is A square units (with respect to the balloon).
Get the point? Finally, it boils down to that the probability of finding matter in the universe will be unchanged no matter how much it expands!
(Dunno how much true this is....this is only based on my thinking...)