What would ET look like?
January 29th 2009 03:09
In this interesting article by Michael Shermer, the odds of intelligent aliens looking like us are considered. Is it at all likely? Are Hollywood's depictions of intelligent extraterrestrials too anthropocentric? Shermer thinks that the odds of ET being bipedal and humanoid are very low indeed. Others think it not unreasonable to suppose that they may well be bidepal owing to convergent evolution. Still others think that it is all but inevitable. For my part, I think that we can't know with any real confidence because the issues are entangled and complex, and there's a great deal we don't know about the prospects for extraterrestrial life (let along intelligent extraterrestrial life) and much else besides (even about evolution on this planet), but if I had to make a guess, I'd say it's fairly likely, given some conditions being met.
An excerpt from the article:
"Occasionally a film or show will depict an alien as a gelatinous blob or an orb of light, which is a good start in the move away from aliens-as-bipedal primates, but the alien-ignorance problem was handled best in the book and film version of Carl Sagan's Contact,in which the extraterrestrial being whom his main character encounters (Ellie, played by Jodie Foster) takes the form of her father (out of her memories) because their presence is so wholly Other she would not have been able to comprehend them otherwise."
This is my own assessment:
First we need to realise that we only have a sample size of one (or at most two, admittedly very closely related) species of intelligent primate, so comparative studies are, for the time being, out of the question. It could be that there is a strong correlation between intelligence and bipedality, but then again, it could be that this correlation will only prevail on worlds with conditions roughly similar to those on ours. We can at least surmise - though very imperfectly, given the tiny sample size - that on this planet, bipedality was the configuration most likely to be associated with intelligence. There could be other configurations that evolution might have actualised, but we just don’t know. As a subset of this, it’s possible that there are avenues open to artificial selection that would not be readily open to evolution in the wild, perhaps because the intermediates would not have been viable and natural selection would have disallowed them.
Life on Earth is life as we know it. Life on other worlds could be radically different - for example, it might use different sorts of energy pathways, a different element for respiration, etc. And the sorts of planets upon which this life resides may also be radically different, with a whole bunch of abiotic factors that must be taken into account (like the strength of gravity, the planet’s proximity to any satellites and other planets, the pressure in the atmosphere, the temperature, and so on). If this is so, then all these factors - to do with the organisms themselves and the environments in which they live - could impose important constraints on the sorts of design solutions open to evolution. If, nevertheless, intelligent life is possible on worlds that are very dissimilar to ours (and that’s a big “if”), then the form that intelligent beings are likely to take will probably be vastly different to us, simply because the sorts of challenges posed by these factors may favour very different solutions, and to the extent that intelligence is favoured, it will likely be arrived at through a very different route to what took place on Earth. However, if planetary conditions and biological constitutions are more like those on Earth, then it is not at all unlikely - and is perhaps even inevitable - that that these beings will resemble us in many key respects (though I would be very surprised if they had, for example, five fingers on each hand and shared most of our mammalian characteristics. In broad outline, though, they would likely resemble us, and I imagine that they would be equipped with at least, say, the capacity for speech and some sort of symbolic representational system like language. They would also have sub-optimalities associated with being bipedal, some surely reminiscent to ours).
As another complication, we need to take into account the pathways that might have been actualised if evolution on this planet could be rewound and started up again, how likely they are to prevail on planets with similar conditions to those on ours, and how likely they are to yield intelligent life if they are actualised (perhaps we could run a simulation some day of a million births of life). If Stephen J. Gould was right, then there is nothing particularly inevitable about the sorts of life that have as a matter of fact evolved. So on each planet, we need to have an idea of the tree of possibilities that is open from the inception of life on that planet.
An excerpt from the article:
"Occasionally a film or show will depict an alien as a gelatinous blob or an orb of light, which is a good start in the move away from aliens-as-bipedal primates, but the alien-ignorance problem was handled best in the book and film version of Carl Sagan's Contact,in which the extraterrestrial being whom his main character encounters (Ellie, played by Jodie Foster) takes the form of her father (out of her memories) because their presence is so wholly Other she would not have been able to comprehend them otherwise."
This is my own assessment:
First we need to realise that we only have a sample size of one (or at most two, admittedly very closely related) species of intelligent primate, so comparative studies are, for the time being, out of the question. It could be that there is a strong correlation between intelligence and bipedality, but then again, it could be that this correlation will only prevail on worlds with conditions roughly similar to those on ours. We can at least surmise - though very imperfectly, given the tiny sample size - that on this planet, bipedality was the configuration most likely to be associated with intelligence. There could be other configurations that evolution might have actualised, but we just don’t know. As a subset of this, it’s possible that there are avenues open to artificial selection that would not be readily open to evolution in the wild, perhaps because the intermediates would not have been viable and natural selection would have disallowed them.
Life on Earth is life as we know it. Life on other worlds could be radically different - for example, it might use different sorts of energy pathways, a different element for respiration, etc. And the sorts of planets upon which this life resides may also be radically different, with a whole bunch of abiotic factors that must be taken into account (like the strength of gravity, the planet’s proximity to any satellites and other planets, the pressure in the atmosphere, the temperature, and so on). If this is so, then all these factors - to do with the organisms themselves and the environments in which they live - could impose important constraints on the sorts of design solutions open to evolution. If, nevertheless, intelligent life is possible on worlds that are very dissimilar to ours (and that’s a big “if”), then the form that intelligent beings are likely to take will probably be vastly different to us, simply because the sorts of challenges posed by these factors may favour very different solutions, and to the extent that intelligence is favoured, it will likely be arrived at through a very different route to what took place on Earth. However, if planetary conditions and biological constitutions are more like those on Earth, then it is not at all unlikely - and is perhaps even inevitable - that that these beings will resemble us in many key respects (though I would be very surprised if they had, for example, five fingers on each hand and shared most of our mammalian characteristics. In broad outline, though, they would likely resemble us, and I imagine that they would be equipped with at least, say, the capacity for speech and some sort of symbolic representational system like language. They would also have sub-optimalities associated with being bipedal, some surely reminiscent to ours).
As another complication, we need to take into account the pathways that might have been actualised if evolution on this planet could be rewound and started up again, how likely they are to prevail on planets with similar conditions to those on ours, and how likely they are to yield intelligent life if they are actualised (perhaps we could run a simulation some day of a million births of life). If Stephen J. Gould was right, then there is nothing particularly inevitable about the sorts of life that have as a matter of fact evolved. So on each planet, we need to have an idea of the tree of possibilities that is open from the inception of life on that planet.
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