Well, the crux with my example is that the dart lands exactly on 0.4. There is an infinite amount of real numbers between 0 and 1, so what is the probability it would land exactly on 0.4? Zero, of course. But that still doesn't make it impossible.
I'm not saying no to the fact that it could have randomly landed there, but given that the probability is 0, I am saying that it is possible there is something else we have not discovered that provides a more probable explanation than chance.
*A different type of analogy is the old spontaneous generation theory for maggots in meat. For a long time, people thought they just randomly appeared. Upon closer investigation, it turns out there were other, more deterministic processes going on.
The probability that it lands on exactly. 4 is exactly the same as the probability of it landing on any other particular number. You place additional significance on . 4, but that is for cultural reasons.
If I flip a coin 5 times in a row, HHHHH is just as likely as any other combination, but humans have the tendency to think that is weird or special.
Anyway...
If I understand your hangup correctly, it seems you are mistakenly thinking that all imaginable possible realities should have been equally likely (as positions on a random dart board would be). Of course this is not true; a reality where snakes developed internal organs that function as internal combustion engines which they use to power propellers is very unlikely indeed. The reason of course is that this reality did not arise by picking one randomly from a bag of all possible realities, but rather developed over time through random mutations that were selected for by natural selection.
Now, of the possible realities random mutation and natural selection could have created, this world could be said to be equally likely. There is not some sort of "future purpose" as Penrose says, that is being driven towards.
Okay, what's the probability of the dart landing on 0.400000? About one in a million, right? It's not zero because the target is only specified to finite precision.
Our universe is also only specified to finite precision; we don't know whether physics is ultimately continuous or discrete, but regardless, we can only measure anything to finitely many digits. So whatever the probability of our universe may be, it is at least greater than zero.
There is additional significance to 0.4. Maybe I didn't clarify that well enough in my original post. "0.4" represents the class of universes that support life in a comfortable way. What do I mean by comfortable? I mean that there are far, far more combinations of universe classes that would result in life that is painful (or even extremely painful). Short lifespans, constant agony as a result of different processes, etc. How do I know this? I don't -- it's just a conjecture (and everyone is just conjecturing too). I could be wrong. But it seems intuitively that there would be infinitely more permutations of a painful but life-supporting universe than the "comfortable" one we live in (I don't mean "comfortable" in the literal sense -- there's still plenty of pain in our world).
Penrose was explicitly talking about biological evolution. If we are actually in a "fine tuned universe" discussion now, then all I have to say is "Anthropic Principle". I don't think there is much more meat there to discuss otherwise. We cannot (yet?) reason about any deterministic processes that may have lead the universe itself to have the constants it does.
Of course we already know about many processes that support the formation and existence of life in this already existing universe. Stellar evolution for example, is a rather healthy branch of scientific inquiry. There are not "mysterious" things at play, unless Penrose and yourself are simply intending to imply that there are still things which we do not fully understand (which is obvious, and that is a very confusing way of stating something so obvious and universally recognized).
