Could a monkey accidentally type out the entire bible if you sat him down in front of a keyboard for long enough?
The odds, given the number of words in the bible, are so incredibly tiny that for all practical purposes we could say it borders on the impossible. The universe is not old enough for it to have happened even if the monkey started typing at the big bang.
That is the argument that creationists often give as their “disproof” of evolution. But what they fail to realize is that, unlike a typing monkey, evolution is not completely random. There is a random aspect to it, but Natural Selection makes sure that it is guided in a certain direction that is dependent on the environment.
So, going back to the monkey, if we sit him in front of a keyboard which is programmed to automatically erase any letter he types that is not the right letter, then he will, indeed, type out the entire bible. How long will it take him? He will finish up Revelation in two-and-a-half years.
So not only is it possible for a monkey to type out the entire bible, he definitely would type it out in fairly short order. Although the monkey is typing random keys, only those keys that are beneficial (the ones that produce the right next letter) will be saved. The others will be weeded out.
This is a good analogy of Natural Selection. Given how it works, it was not only possible that all life on earth could have evolved, it was virtually mandatory that it would.