Originally posted by TitusvE
There are a few points:
i) What is the beginning of life? cells, amino-acids, DNA, RNA.
ii) One should be careful when using Occam's razor. The universe has an uncountable number of planets. So even if the creation of life might be might be very small on an individual planet (maybe smaller than on earth), the event of the creation of life on any of these So you could argue that had Occam's razor at their side. Now we know it is more complicated!
“...i) What is the beginning of life? cells, amino-acids, DNA, RNA. ...”
cells; or at least “photocells” (the distinction being blurred) . Amino-acids, DNA and RNA don't by themselves really count as what we normally mean by “life” unless you are talking about viruses (which I personally think should be classes as “living” despite the general opinion to the contrary) but viruses cannot reproduce without cells.
“...ii) One should be careful when using Occam's razor. ...”
yes, I know. I have studied logic.
“...The universe has an uncountable number of planets. So even if the creation of life might be might be very small on an individual planet (maybe smaller than on earth), the event of the creation of life on any of these planets might be much higher in total, relative to the creation of life on the planet earth alone ...”
As Shallow Blue has indicated, there is the thorny problem of the chances of life surviving the trip from another planet to Earth esp if it come from another planet other than in our own solar system! Could life really survive being thrown into space by an impact AND then survive such a long trip without liquid water AND then survive being baked as it enters the Earth's atmosphere AND then survives the impact ? -that is assuming a lot! Also, even if it DID come from another planet, it couldn’t have come from more than, say, 140 million light years away because, even if it travelled as fast as 1% the speed of light towards Earth (unlikely) and somehow survived the impact at that massive speed (unlikely) , the age of the universe (just under 14 billion years old) isn't old enough to have allowed time for it to reach Earth from that distance soon after Earth's formation so “...The universe has an uncountable number of planets...” is not what is relevant here but how many suitable planets (one’s with liquid water) were there before Earth within, say, a 140 million light year radius (and not planets outside that radius) is what is relevant to that hypothesis -and that totally ignores the problem of the fact that the further that planet is away from Earth, the lower the chances that a lump of rock from it containing life would just happen to head exactly toward Earth!
“...Occam's razor is often misused to conclude that a simple mechanism is more likely than a complex one ...”
yes, I know. I have studied logic. Occam's razor merely recommends that we should be more certain of the theory/explanation that makes the least unnecessary assumptions to account for all that is observed. That's why I said in my post “The least assumptive
hypothesis (and therefore the best) is that ...” and NOT “the simplest