Stranger, thanks for another eloquent post – much appreciated!
It’s absolutely what most of us have in mind, I think – certainly what I have in mind. I don’t know about crows or octopuses, but certainly wolves and other canines, and there are certainly hundreds of species that are clearly sentient and possess problem-solving skills – intelligence by any reasonable definition. As lalaith said, quoting Darwin, “the difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind”. A plausible argument for the commonality of life in the universe is the tremendous diversity that has evolved on earth, and the repeated re-establishment of that diversity after great extinctions. It’s not a slam-dunk conclusive argument but it certainly suggests that life-forming and biological evolutionary processes are pervasive. If humans were the only life on earth that might suggest something quite unique and perplexing, but in fact the opposite is the case.
Still, if life were found elsewhere in the solar system, which is still possible, it would be a much more conclusive argument, though I would venture the WAG that it’s very unlikely. Though even then some would raise the argument of cross-pollination from a common origin.
I would disagree with your point, if I understand it correctly. The scale of the universe isn’t the same scale we use. Your function might be not flat at all, without it being of any relevance to us. For instance, if life appears on average once every 10 billions years in an average galaxy, that’s a lot of life in the universe, given its size. But it still means that we probably will never find another planet with life.
I don’t think so. People discussing the possibility of finding intelligent life have advanced civilizations in mind, not the local equivalent of dogs.
Also, both crows and octopuses are considered highly intelligent, and the latter are very good at problem solving. I didn’t pick them at random.
So, this doesn’t really address my points. We still don’t know if life appearing to begin with is likely, we don’t know if complex life appearing is likely, we don’t know if conditions on Earth are or were exceptionnaly favorable (like in the moon example where it takes an early collision creating a kind of binary planet for life to thrive).
It is true that we don’t have empircal data, so any answer to the question is speculative by default. However, we can observe that the essential chemical precursors–the amino acids–and structural and nutritive elements are readily found in non-terrestrial environments. The conditions that existed on primordial Earth–the reducing atmosphere, liquid water, silicate matricies, and so forth–would not seem to be unique in any way to our world. Assuming the abiogenesis of life on Earth was not due to some completely unique event, a twist of quantum interactions never seen before or again in the history of the Universe, a cumulation of plausible conditions leads almost inevitably to emergence of sophisticated, pattern reproducting systems and thence to life as we might recognize it. We don’t need to expand the net across the entire universe, or even a galaxy, to get enough occurrences of even an unlikely single condition; the rate of chemical reactions in even a small beaker of a few mols of reactants is millions or billions of times a second. A random cojoining of individual amino acids into an autocatalytic, self-reproducing structure, while not yet demonstrated in a lab without using life-generated precursors, is not far from probable given sufficient time and energy. The notion of life being created “once every 10 billions years in an average galaxy” is exactly what I’m referring to with the afformentioned Law of No Small Quantities; we would either expect no life (because it is physically impossible) or common life (because even a very tiny probability of an occurance of favorable conditions and consituants per unit time integrated over across hundreds of billions of solar systems and billions of years still results in a very high aggregate potentiality), not just once or twice in several thousand billlion billion planet-years.
Arguing that life must only be able to be generated in very Earth-like conditions, and especially insisting on very specific parameters such as axial tilt, atomspheric composition, or accompanyment of a large moon is nothing more than special pleading; out of the subset of all plausible conditions under which life may emerge that may be our particular path, but it doesn’t mean that this is the only possible (or even most probable) path. We simply cannot restrict our conception of the emergence of life to our particular experience unless there is some very strong argument of uniqueness beyond “that’s all we know.” All cats are black at midnight only if the researcher isn’t willing to turn on hte light or admit ignorance in the lack of illumination.
Multicellular and complex, cognitive life forms are more difficult to argue strongly for just because of the number of necessary bottlenecks to get there and the uncertain evolutionary pressure to develop intelligence (Escherichia coli certainly has had no need for it) but even if we assume that intelligence is orders of magnitude of greater evolutionary difficulty beyond prokaryotic-type life, a proliferation of different solutions to selective pressure argues for the development of cognition in some form, although whether it would be developed to the extent and in anything like recognizable form to human intelligence (or other arguably intelligent non-primates) is highly speculative, and how well it may contribute to overall evolutionary fitness over a really long term isn’t even demonstrated in our particular case. Given that complex problem solving intelligence and sophisticated communication skills have evolved independently across dozens of orders or families of species demonstrates that there is some special value in cognition to at least that extent.
And for all we know, instead of being special and unique, one of the first truly intelligence species to emerge in our own galaxy or local neighborhood, we may be well behind the curve, still mired in badly designed cognative structures and trying to count probability distributions with discrete numbers, the cosmic equivalent of monkeys banging away at typewriters to produce the tragedy of the Dane. Perhaps the reason we see and hear nothing is that everyone else has moved on while we were still growing skeletons and emerging from the oceans like flapping fish.
We may not have empirical evidence that life is common but there really isn’t a substantial argument for why Earth or the emergence and evolution of life upon it would be unique, and every time we insist on asserting some special property we are ultimately disappointed to find that we’re not unique at all. Not at the center of the solar system, or the galaxy, or the universe; not made of special “living matter” or powered by an élan vital; not the only world with liquid water or geological activity; and probably not the only life in the universe, even the very nearby part of it.
Huh, I thought there were already several Earth-like planets found in habitable zones around Sun-like stars. Or at least, close enough for government work (e.g. super/mega earths).
As always, what’s the news media’s definition of “Earth-like?” The answer is that each new planet that’s discovered that has any feature at all in common with Earth is described as Earth-like. And as our search tools get better, we’ll be finding planets more Earth-like than previously.
So this news is simply that a new record has been set in degree of Earth-likeness. Which record will stand for a few months or years until an even more similar planet is found.
At which point the breathless news “Earth’s twin found!!!” will once again grace the world’s new sites & blogs for a couple days before being displaced by the latest instance of some celebrity behaving badly.
