[list=a][li]You’ve made an affirmative claim, to wit: tool-manipulating intelligence can only occur in bipeds, and have failed to present proof of it, despite examples to the contrary.[/li][li]There is no “proof” that any number of other legs would be ideal, useful, or possible for a terrestrial vertebrate in the form of example because it hasn’t happened, and indeed the purpose of that line of reasoning is to indicate that evolution of life on Earth hasn’t demonstrated an exploration of all possible alternatives and dismissed them in favor of quadrapedal (and later, bipedal) locomotion. Four limbs (or deprecations thereof) are endemic of terrestrial vertebates because that number was, as far as we can tell, the number of existing lobes on primative lungfish. Furthermore, we have every reason to believe–from the study of anatomy, evolutionary zoology, and molecular biology–that adding more locomotive limbs to an existing complement is irreducibly difficult. Four is the number because it was arbitrarily first, not because it is some kind of evolutionary optimum, as evidenced by a wide variety of other numbers of limbs in insects.[/li][li]Various species of octopus have demonstrated very high levels of conceptual and problem-solving intelligence, and while not social creatures in the sense of habitat or defense, they show a remarkable degree of visual communication skill in experiment. As they lack vocal or sound-generating capability (not a part of their cumulative form, see) they don’t have the ability for speech or hearing, but they have an enormous brain compared to body mass, and have a visual cortex roughly comperable in complexity to primates. The main restriction, it would seem, in more extensive evolution to developing social intelligence and capability is their reproductive cycle; they die (by function) not long after impregnating or laying eggs, and thus don’t have the kind of extended social or familial contact that is common among the more intellegent vertebrates.[/list]At this point, you seem to be dedicated to defending your thesis despite a complete lack of rationale beyond appealing to the extant but highly limited dataset of life on Earth, and are in your own words adverse to considering even contraditions therein, rather than engaging in honest discussion or debate. Evolution and natural selection are not simple processes that are readily analogous to simple chemical reactions or mechanical thermodynamics, and generally can’t be boiled down to a simple set of rules that follows a linear and inalterable path toward a preconceived or universally optimum solution. The fact that you don’t understand this suggests that you need to spend some more time reading up on the field rather than preserving a facile and unsupported claim.[/li]
Stranger
Uhm, invertebrates adapted to terrestrial life before vertebrates, so we know that creatures with more than 4 legs were the first to walk on land. The earliest footprints found are well over 500M years old and belong to some type of arthropod.
Why are they limited, and why couldn’t the trunk evolve to be more useful in manipulating tools?
Depending on how you define intelligence, octopuses have developed it. And there are many aquatic animals that communicate quite well-- there is no reason to think that that environment is not amenable to the evolution of language.
We’re arguing hypotheticals; how can you reasonably expect proof of anything hypothetical? Heck, you haven’t offered any proof for your own hypothetical. Either the logic behind our explanations is sound, or it is not. I am of the opinion that it is; constraints are known to exist, body plans are known to be difficult, if not impossible, to modify in a substantial manner. Intelligence has manifested itself in non-humanoid, even non-vertebrate, forms here on Earth. There is no reason at all to believe that human (or human-like, if you prefer) intelligence is the only viable form of intelligent life.
Language is necessary for telling someone else what you know; it’s not necessary for being able to figure things out on your own. Cephalopods and elephants may not be building skyscrapers or flying saucers anytime soon, but that doesn’t mean they don’t have their own sort of intelligence (not to mention, they do possess forms of communication).
Given that we have not evolved telepathy, we don’t know what’s new to you. We can only infer, based on your arguments here.
If the universe is infinite, then there is not only 1 other planet with humans on it. There is an infinite number.
And there is an infinite number of planets with a straight dope message board on them.
And an infinite number of people making this exact post, in English.
What are the odds that a mod will finally put this thread out of its misery?
Maybe for telling what you know but not for passing on what you know. Female cats teach their kittens to hunt, wolves, bears et al teach their young how to survive.
I saw a movie of an octopus given a jar with a crab inside. It couldn’t get the lit off to get at the crab. Thn an octopus who knew how was put in an adjacent tank. This one unscrewed the cap and grabbed the crab. The first one immediately grabbed its jar and after some trying got the cap unscrewed.
It is true though that language is necessary in order to pass on information widely and to those with whom you have no direct contact. If I could read the language I could learn directly from Galileo.
More importantly language is necessary for passing on information without exposure. I can tell you not to open your jar because it contains a poison, even thoug mine contains a tasty crab dish. An octopus is incapable of doing that.
Passing on information through demonstration alone is actually a terrible way of doing things and little better then trial and error. It is completely useless for teaching about things that are not demonstrably present in the environment right now. A wolf can teach its young how to hunt deeer, provided it encounters deer before weaning. In contrast I can teach my child how to hunt without her ever needing to see see the species.
The problem is, my ideas of how evolution has worked are being summarily rejected without a shred of evidence, yet I am expected to provide detailed proofs that humanoid intelligent life is likely. I’ve given, my ideas on tetrapods and how they would lead to bipedal forms. I think there are mechanisms of evolution that aren’t understood yet. I think these mechanisms will explain why we see some forms but not others.
It is just beyond reason to everyone else in this thread that I could have the same information, yet arrive at a different conclusion. As far as i can tell, everyone else has a perfectly valid view of how evolution occurs. My view is valid too. If you have proof that my view isn’t valid, then please present it.
You haven’t provided any evidence to support your rather strong and specific claim, nor addressed stated examples to the contrary. And now you’re arguing to ignorance, to wit, that there are “mechanisms of evolution that aren’t understood” which proportedly support your claim, or at least will once someone discovers them. This is a position without factual merit or basis; there is no credibility here to say that bipedalism is an inevitable result or a requirement of high intellect; the most that can be said is that the singular example of a complex, tool-manufacturing species we have available to evidence is bipedal. One data point does not a statistical prediction or basic principle make.
Stranger
Not really. You’ve posted stuff that isn’t even about evolution, thinking that it was (ie, genes that don’t affect reproductive fitness). You are taking what you know about chemistry and assuming that there must be a parallel in biology. You are insisting that just because form A is present now then form A must be essential in some way, when we know that isn’t true. In fact, that’s more akin to creationism or ID than to evolutionary theory. I’m sure you’re a fine chemist, but you simply don’t have a good understanding of evolutionary theory.
I’m not a biologist either-- my training is in physics. But I know enough about evolutionary theory to see that you are just plain wrong. If you don’t take if from me, take if from **Blake **and DF, both of whom are biologists.
Then tell me what you know that I don’t.
I don’t know, but if the universe is infinite, then maybe there are an infinite number of “What are the odds of humans evolving on a different planet” threads, many of which have already been closed by the mods.
As others have pointed out, everything doesn’t take the path of least resistance, even in chemistry.
In which case your position is entirely circular, and thus entirely illogical, and can thus be discouted out of hand.
You claim that things most frequently follow the path that is easiest. Then you define easiest as paths that are most statistically probable. And you can only determine which paths are most statistically probable by observing wich paths are utilised with the greatest frequency.
Your whole position has beocme hopelessly circular. Unless you claim to have some mathematical method by detecting a priori which path is most likely to be used your argument is completely illogical.
All genes are detrimental if we restrict ourselves specifically to defintions that excalude reporductive success. No excuses, no exceptions, all genes are detrimental. Just consider the genes responsible for the bipedalism that you think is so vital. They are massively detrimental to the ability to bar live young and the ability to move without incurring spinal damage.
By “not talking about genes that are specifically detrimental to reproductive success” you have demolished your own position and forced us to accept that bipedlaism is in fact detrimental rather than beneficial.
Nonsense.
Your ideas are being rejected because they are based on demonstrably flawed reasoning and are demonstrably not true.
Claiming that there is no evidence that things follow paths of high resistance or that there is no evidence that all genes are detrimental is simply not true.
That’s right, youmade the positive claims, you have to provide evidence. We only need to provide couterexamples to flasify those claims. You’re a scientist, oyu should know this.
And others have pointed out how those ideas are based on erroneous ideas.
I think there are mechanisms of evolution that aren’t understood yet. I think these mechanisms will explain why you are completely wrong.
Where does thta leave us? Does that seem like a good reason to accept what I say? This is the problem with the argument from ignorance, it can be used to support absolutely any position at all.
The trouble is that you have demonstrated that you don’t have the same information. There is a lot of information that you clearly lack.
No. Science doesn’t work on the "I’m OK you’re OK principle. Only one view can be a valid reprsentation of reality. That may be a view that isn’t being expressed, but it is impossible that two or more opposing views are all valid.
We have. Logical fallacies, factual errors and misundertsanding of evolutionary theory all invalidate your view.
See the above Mayr and Dawkins recommendations for a basic starting point in understanding evolution and natural selection as currently accepted.
Oh no you don’t! This is why I prefer Bohmian mechanics to the Many Worlds interpretation. It’s all nonlocal hidden variables as far as I’m concerned. Hugh Everett was such a wanker. 
Stranger
Oh do please give me that chemistry example.
I don’t think that the detrimental comment refered at all to bipedalism. I realize now that I made an error here. Given a large enough sample size, a neutral gene will survive 100% of the time. For genes that are advantagous or disadvantagous you need a time variable to determine the % survivability. The longer the time, the steaper the slope, but essentially once you get to infinite tima all genes that are dissadvantaguos will be selected out and all the genes that are advantaguos would be selected for. Still not sure what this has to do with the argument.
Yes this is true, but the absence of proof isn’t proof that I’m wrong.
I must have missed this. Did someone come up with an example of a six legged vertebrate?
So you think there are unknown mechanisms of evolution that would preferentially select for a path our planet didn’t take? That’s interesting.
Well, I can’t say that your post has exactly broadened my knowledge.
I haven’t seen why my position isn’t valid yet. I’m sure you’ll clarify it soon though.
Must have missed all that. This last post certainly didn’t clarify.
[Moderating]
Sorry, Christopher, if you have missed all the ways in which your positions have been refuted in this thread, then the effort is probably wasted. At this point, you seem to be arguing just for the sake of arguing, and not contributing any actual information. I’m going to declare the question asked and answered as far as GQ can take it. If you want to continue this discussion, take it to GD. I’m going to close this thread.
Colibri
General Questions Moderator