you right.. except by this:
Anyone can start writing down numbers and stop after reaching an certain number of digits, but it is impossible to have an infinite array, because theoretically you can have a number so large that it could not be written in font the size of a single proton across the entire universe (unless you argue that the universe is infinite, but I won't go into that). Because these numbers cannot be defined in any real way, a cap must be applied to the array in order to draw any real number from it, even if the cap is subconscious.
I'll not discuss who is right or wrong about the size of universe... But I have a question for you: If it was finite, when you got to the end of it, what would be next? nothing? well, I myself believe not. Something must be after there... there's aways something after...
About a number who couldn't possibly be writen down... There's no such number... every number can be writen in a notation who could subtract the size of it to a few numbers below 100.
Possibilities are infinite. First, almost everyone is stuck by the "normal" way to write a number, that is, when it reaches ten, a new digit is add. but you could use hexadecimal witch adds a digit only when it reaches 16, or even use a notation witch only adds a digit when reaches 100.
second, there's a lot of notations to make large numbers smaller... The most famous is the scientific notation, but there's the Graham's number notation, too, witch uses tetration and knuth's up arrow notation:
http://upload.wikimedia.org/math/3/5/f/ ... 4f4b38.png[/img]
there's lots of other notations there, and you could easily create a new one.
as you said, a number too big to be writen is just theory, so, there's not much to add here.
as to the propabilities, yeah, I was equivocated. I myself said to abandon finite numbers intuition, and finished using it... XD
As I said, when working with infinite numbers, all propabilities become infinite. so you don't even have to write infinite*infinite = infinite (simply because there's no such calculation), you just have to know that the possibility is infinite itself.
As for the impossibility of taking a random number in a infinite array, I still doubt that. The computer, witch I'm using and you're using and I'm using right now, just can't do that because it don't understands the concept of a number, it just have an array of them in it's memory. but a mechanism advanced enought could get close to "learn" this concept, close enough to create it's own numbers. If it can create a number, randomizing any number from 0 to infinite would be piece of cake.
and, to talk a bit out of the topic's subject: In the medieval era, no one tough there would be more earth after the ocean... But now we already got to the moon... History only show that our mind is aways a bit closed comparing to the mind of future generations...