LogicGates

Jens, wow thank you for the above replies, which have opened up whole new lines of knowledge for me. Not being a biologist, and having read mostly popular materials on this subject, I did not even know that Carl Woese existed; and now I learn that this famous and acclaimed person gave detailed arguments to support what I only fancied intuitively. This makes me wonder even more than before, why Dawkins stated the theory of a "common ancestor of all life on earth" as if it were a foregone conclusion, and that the probability of life arising spontaneously was assumed to be so incredibly small - and why everyone (at least in the popular works that I've read) agrees with him. All these links you've provided are going to keep me busy for a while. Thanks again!

Mister McDougall, please get out of here and quit cluttering up our science forum with your pathetic attempt to disguise your religious motives. Just a quick glance at your blather and one sees your preposterous, discredited claim that Albert Einstein believed "Intelligent Design". Like all "Intelligent Design" proponents you smother us with Hogwash. Serious posters here put considerable effort into discussions that help us understand reality. Go read a mythology book. BEGONE !!!

Perhaps I did not state my original question clearly enough. Sorry if that's the case. It seems that my question was interpreted as "Couldn't Abiogenesis still be happening today?" What I meant, was "Couldn't Abiogenesis have happened multiple times (and in multiple places, for that matter) way back during the epoch when it first started happening?" And these independent occurrences of the chemical precursors to life could look just like each other because they spontaneously arose in the same conditions. If the conditions were right for it to happen once, then perhaps they were right for it to happen twice, three times... N times. Then, if they all "looked alike", they could combine and evolve from there.. and what now may appear to be a single common ancestor could really be multiple common ancestors.

Thank you all for your thoughtful and illuminating replies. I have gained insight from them, but I must say, respectfully, that most of you have (no doubt unintentionally) skirted my question. You have skirted it by reiterating/rephrasing/amplifying the very same standard argument presented by Biologists to which I am objecting in the first place: That is, you have once again spoken some *words* about how improbable Abiogenisis "seems", based, once again, on your *intuitive* arguments to support your views. Jens, you say "that biochemists and microbiologists tend to assume that abiogenisis is highly improbable and physicists tend to assume that it is simple (since they typically do not know the details)", but shortly before that you say "you tend to think that abiogenesis is a highly improbable event, because there is no simple solution of how a primitive self replicating and evolving molecule (or molecule system) could look". It sounds almost as if you're saying that Biologists assume it's *complicated* because they don't know the details, while Physicists assume it's *simple* because they don't know the details. But I would like to point out that Physicists do not assume that something is simple because they don't know the details. Physicists do look for the simplest form of the underlying fundamental laws that will successfully explain the thing they are studying. But that is far from assuming that the solution to something complex, will be simple if you don't know the details! We do have confidence, in Science, that Biology is based upon Chemistry, which is turn is based upon more fundamental physical laws at the smallest level. The fact that mind-bogglingly complex chemical reactions occur in nature, does not change the fact that, given a certain range of conditions, with a certain set of chemical ingredients, we can expect an ensemble of such systems to evolve in a way which is, in principle, predictable. Thus, based upon these "word" arguments that we all seem to be using since we don't in fact know the complex details well enough to calculate our probabilites, it seems completely logical that, given the right conditions in nature, Abiogenisis could indeed take place multiple times independently, and produce the same arrangement of chemical elements and compounds required to become self-replicating. My original question, was simply, that unless and until we gain enough knowledge to really be able to make probability calculations, at least with some statistical degree of confidence, are we not completely unjustified in continuing to insist that Abiogenises is "extremely unlikely" to happen more than once? I firmly believe that we *are* completely unjustified in proclaiming that. Note that I'm also not proclaiming it to be "extremely likely" either. I'm simply saying, I don't know. And I think, neither does anyone else. I propose that we wait until we can say, for example, "The probability of Abiogenisis under set x of conditions, is 52.2 percent, +/- 7 percent" (for example). Until then, let's quit using phrases such as "extremely unlikely". Finally, let me ask you all to consider the following two well known facts, in helping to think about whether you have the right to proclaim Abiogenisis "extremely unlikely" simply because you don't understand the complexity of how it happened. (1) It's well known that complex fractals are generated from very simple laws, in a predictable manner. (2) It is recently confirmed by Astronomers that many planets in far-flung galaxies, exhibit spectra that indicate Methane, which implies life. If the chemical properties of methane are the same in all those far flung galaxies as here, then why would you reject the notion that the chemical characteristics of Abiogenisis might be the same out there in all those places?

Why are you guys arguing about religion? I thought this was Science Forums! Religion hasn't a blessed thing to do with Science!!! Take you ridiculous arguments somewhere else, please!

Hello all, I just registered here at Science Forums. I've read (actually listened to) Darwin's "Origin of Species" and am reading Dawkin's "The Ancestor's Tale", and have read a number of other articles on evolution, and seem some mention of speculations on the origin of life on earth. It seems that, like Dawkins, almost all professionals and students of biology take the view that all living things must have a single common ancestor, because Abiogenises is "extremely unlikely" to occur more than once within an extraordinarily long time span; and furthermore, that since all known life shares the same kind of DNA molecule, it would be "extremely unlikely" for such DNA to again form spontaneously from non-living chemicals. Repeatedly I read such verbal arguments. But isn't it fair to ask, how everyone can claim that it's "extremely unlikely" without at least showing some kind of calculation to derive a numerical estimate of this supposed "extremely unlikely" probability? I appeal to Lord Kelvin's famous statement, "when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be". No insult to biological science intended here, because I know it has advanced mathematically to a tremendous degree. But until such time as biological science, coupled with chemical science perhaps, can come up with some quantum-chemical calculation that provides a numerical estimate of the probability that Abiogenesis is indeed "extremely unlikely", is it unfair to ask everyone to quit making this claim, at least for the time being?