I think the real question with the probability of life starting is eactly how easy it is to create life or even a good reproducing state given the proper conditions. What makes it dificult is that probabilities shrink very rapidly. If you cover every planet in the universe with billions of monkeys each typing randomly on typewriters, starting a new try every week for billions of years, they will never write Hamlet. They won't even get the first line. The probability to type the right n characters is 63^n, which grows exponentially. We can think of giant volumes of planets, but the number of planets will only grow linearly with the volume. The probability of creating even basic constructs is very small.
Even if you do manage to create a basic reproducing construct, that doesn't mean you are finished. The reproducing construct will only have a limited number of instances on its single planet. So once again, it is difficult to get to the next step beause your numbers are small relative to the the imaginable probability (of course what this is is not known).
On the other hand, the probability of us observing intelligent life is 1, since the intelligent life is the observer. No matter how few planets develop intelligent life, each will look at itself and say, "There it is." Our own existance or the history on our planet says nothing about the probability of life evolving without knowing the number of "tries" that failed to evolve life.
People who agree with what I have said so far may disagree with this next part, and that is ok. In counting the number of tries, we don't know that there is only one universe in which those tries exist, meaning we could be the only ones in this universe, and ours is one of the relatively small number of universes that have life.
Of course, I can't say the probability will be small. But I think it is also unfair to just assume the probability of life evolving is big.
Even if you do manage to create a basic reproducing construct, that doesn't mean you are finished. The reproducing construct will only have a limited number of instances on its single planet. So once again, it is difficult to get to the next step beause your numbers are small relative to the the imaginable probability (of course what this is is not known).
On the other hand, the probability of us observing intelligent life is 1, since the intelligent life is the observer. No matter how few planets develop intelligent life, each will look at itself and say, "There it is." Our own existance or the history on our planet says nothing about the probability of life evolving without knowing the number of "tries" that failed to evolve life.
People who agree with what I have said so far may disagree with this next part, and that is ok. In counting the number of tries, we don't know that there is only one universe in which those tries exist, meaning we could be the only ones in this universe, and ours is one of the relatively small number of universes that have life.
Of course, I can't say the probability will be small. But I think it is also unfair to just assume the probability of life evolving is big.