Quote:
Originally Posted by jamesdmanley
im not sure i really follow your argument, but i dont disagree with anything youve said. of course we live in the universe in which it happened. if it happened somewhere else thats where we would be. i certainly dont think we are the only life in the universe. the odds are greatly against that, but i dont think it happens on accident. its just far too complex, precise, and fantastic.
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The point of my argument is that if DNA
hadn't spontaneously come about by chance on the Earth, then we wouldn't be here talking about it. It doesn't matter, therefore, if it stood only a 1 in a billion chance of happening by chance - we just happen to be in the situation in which it
did happen; therefore no matter how unlikely it is to happen by chance, we are the outcome of that vanishingly unlikely event actually happening.
I actually don't believe it's all that unlikely. I don't know if you've read about the experiments people have done, seeing what could have happened through "random chemistry" on the primitive Earth? Basically people have put water, methane, and ammonia (that's what we believe the main constituents of the atmosphere of the very early Earth were) into a pressure vessel, and just let it "cook" for several weeks, passing jolts of electricity through it to simulate lightning. At the end of several weeks, they've analysed the "soup" that's formed to see what's in it. They've found that surprisingly complex organic molecules form, up to the level of amino acids.
If that can happen in a few weeks, imagine doing that, on a planet wide scale, for hundreds of millions of years. Sooner or later, by chance, those amino acids are going to join together to form proteins, and perhaps - who knows? - a random group of proteins will, by chance, come together to form DNA, a molecule with the interesting chemical property of being able to replicate itself, ie "life"? It only has to happen
once amongst all the other virtually incalculable number of chemical reactions that don't do anything "useful".
Is life so unlikely given those circumstances? Some people would say not.