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It sounds like you're calculating the likelihood of a human evolving in an instant though? Which doesn't need to happen and isn't presumed to have happened her

It sounds like you're calculating the likelihood of a human evolving in an instant though? Which doesn't need to happen and isn't presumed to have happened here on earth. Intelligent life doesn't have to be like us at all, it doesn't even have to use DNA (although intuitively it does feel like it would need some similarly-complex form of reproductive instruction... eventually). According to evolutionary theory early life on this planet was something far simpler than us (eg. some form of self-replicating molecule - depending on your definition of life) and evolutionary forces (imperfect reproduction leading to variation along with 'survival of the best fit') do the rest of the work. It's vastly unlikely that it would take all the same forks in all the same paths and end up as something like humans (or even like vertebrates - the whole tree of life begun from scratch on another planet would likely be unrecognisable to us) but it seems (again, intuitively) like something akin to what we call intelligence would eventually arise due to the competitive advantages it offers.

gpsx 10y ago
My comment was trying to address the idea of big numbers. People can say there are so many planets there must be other life out there. But relative to the numbers that can be involved here, 10^22 is not that big of a number. You raise two very good points. The first (or really second) is multiplicity. For the DNA example I gave, there are many different valid human DNA patterns, and there are surely many non-human good patterns. We divide out number of parameters by the multiplicity. I don't think this generally have a big effect on the size of the _exponent_ we are talking about even if it does change the number by a large factor. The other point is that this was an evolutionary process. What this means is that we could stop and save our work along the way, due to reproduction/replication. When the monkeys try to type Hamlet, they have to start over each time. If one gets the last character wrong, it is back to the drawing board. A better evolution analogy would be if the scientist could stop a monkey when he got the first paragraph and then give that as a starting point for other monkeys. This _does_ seem like it could make a big difference in the size of the exponent. Back to the size of that exponent - it is roughly the number of components of the system. We are composed of 10^29 atoms. There aren't even that many planets, let alone a number raised to that exponent. Even the most simple life consists of many atoms, but the size of our universe only supports putting a small (100?) number of components together. Given this, I am personally still skeptical the universe is big enough to create life besides us. I do have one more thing I want to mention related to why life looks easy. When we look back at our evolution, it looks like it was easy, even inevitable. But there is one thing to consider. Imagine we lined up 10^300,000 monkeys or whatever it would take to type Hamlet, and we put a scientist behind each one to check the monkey's work. Imagine if you were the scientist behind that one monkey that actually pounded out all of Hamlet. Given that you did not see the other 10^300,000 attempts, what would that look like to you?

gpsx 10y ago

My comment was trying to address the idea of big numbers. People can say there are so many planets there must be other life out there. But relative to the numbers that can be involved here, 10^22 is not that big of a number. You raise two very good points. The first (or really second) is multiplicity. For the DNA example I gave, there are many different valid human DNA patterns, and there are surely many non-human good patterns. We divide out number of parameters by the multiplicity. I don't think this generally have a big effect on the size of the _exponent_ we are talking about even if it does change the number by a large factor. The other point is that this was an evolutionary process. What this means is that we could stop and save our work along the way, due to reproduction/replication. When the monkeys try to type Hamlet, they have to start over each time. If one gets the last character wrong, it is back to the drawing board. A better evolution analogy would be if the scientist could stop a monkey when he got the first paragraph and then give that as a starting point for other monkeys. This _does_ seem like it could make a big difference in the size of the exponent. Back to the size of that exponent - it is roughly the number of components of the system. We are composed of 10^29 atoms. There aren't even that many planets, let alone a number raised to that exponent. Even the most simple life consists of many atoms, but the size of our universe only supports putting a small (100?) number of components together. Given this, I am personally still skeptical the universe is big enough to create life besides us. I do have one more thing I want to mention related to why life looks easy. When we look back at our evolution, it looks like it was easy, even inevitable. But there is one thing to consider. Imagine we lined up 10^300,000 monkeys or whatever it would take to type Hamlet, and we put a scientist behind each one to check the monkey's work. Imagine if you were the scientist behind that one monkey that actually pounded out all of Hamlet. Given that you did not see the other 10^300,000 attempts, what would that look like to you?