Comment by uplifter
4 hours ago
What part of it don’t you agree with? That an algorithm implementation must encode the goal that it pursues? How can something pursue a goal it has no access to a definition of? If you have an alternative way it could work, please propose it.
I’m not asking rhetorically, I’m truly interested in learning the flaws in my argument for why natural selection cannot be modelled as an optimization process. So if you have the time to reply with a more detailed rebuttal, I’d much appreciate it.
edit: Addendum: I recognize my claim that computer scientists might have an advantage in understanding this is contentious, and I was not implying that they (we) as a group have a better record of understanding evolution’s subtlety than biologists (which I studied in uni) or the average lay person. I just think they could have an advantage in understanding the version of the argument that I gave above, and I am interested in improving it for that purpose.
What is the algorithm implementation when it comes to the physical world? Does the implementation extend to remote galaxies? Is the strong force part of the implementation? We don't know ... there appears to be no way to know.
But even if you could know, it is just demonstrably wrong that the implementation must encode the goal. If you create selection pressure, and have a reproductive system that allows for mutations, then you may end up an "implementation" that encodes the goal implicit in the selection pressure. But anyone who messed around with genetic algorithms or artificial life in the 90s knows that you can trivially start out with no resemblance to "the goal" at all. Where life on earth in aggregate or any specific example of it in particular might be along that pathway is similarly impossible to say.
Finally, even defining "the goal" is tricky. Consider the well-documented case of moth evolution in industrial (and later, post-industrial) northern England. Their camouflaging wing tones changed to respond to the typical color on vertical surfaces, twice within a human generation or three. Was "the goal" flexible coloration across generations, or was it "light, then "dark" and then "light" again? That's a philosophical question as much as anything ...
> What is the algorithm implementation when it comes to the physical world?
It is the physical world, nature is the implementation of the natural selection algorithm. Yes, the strong force is part of the implementation, because the strong force can play a role in selection events, cf nuclear bombs and radiation. The gravitational pull of remote galaxies can also influence selection events by changing planetary orbits minutely.
I don’t see these as problems for my argument because I am not the one claiming they encode an objective, I just see them as natural forces which can influence selection without any overarching purpose or goal. It is those claiming natural selection is an optimization process who must show how it could work. The onus is on them to show where their supposed objective of natural selection is encoded in its implementation.
> If you create selection pressure, and have a reproductive system that allows for mutations, then you may end up an "implementation" that encodes the goal implicit in the selection pressure.
What goal are you referring to?
> But anyone who messed around with genetic algorithms or artificial life in the 90s knows that you can trivially start out with no resemblance to "the goal" at all. Where life on earth in aggregate or any specific example of it in particular might be along that pathway is similarly impossible to say.
I am one of these people, but I don’t know what goal you are saying these systems came to demonstrate. Are you saying these artificial evolution systems had objectives they pursued? What caused them to follow these objectives? What is this “pathway”?
>Consider the well-documented case of moth evolution in industrial (and later, post-industrial) northern England. Their camouflaging wing tones changed to respond to the typical color on vertical surfaces, twice within a human generation or three. Was "the goal" flexible coloration across generations, or was it "light, then "dark" and then "light" again?
There was no goal at any point in the process. Moths with colors that matched their contemporaneous environment were less likely to be eaten by predators than those which stood out. Calling it a goal is a confusion, its trying to add a conceptual framing that isn’t necessary and adds nothing to the understanding of the system. Neither the soot levels in the air nor the birds hunting for moths have a goal of adjusting the balance of moth coloration phenotypes. They are just the context, along with everything else in their environment, in which evolution of moth coloration may occur.
In what sense is there any goal in the example? And if it is a goal, why is it not optimization? I claim there is no goal, no optimization objective to natural selection. Its not just a philosophical side question, it is the question.
edit: typo
> It is the physical world, nature is the implementation of the natural selection algorithm.
But you don't know (and to some degree, cannot know) which parts of it. So you cannot really know if the implementation encodes a goal or not.
> What goal are you referring to?
Whatever goal was being used in the case of genetic algorithms or artificial life systems. Those systems have goals, but the early stages do not embody the goal in any way you could recognize.
> There was no goal at any point in the process.
So in the case of natural evolution, we happen to agree. However, I don't agree with your claim that "the implementation must embody the goal" is a useful way to think about this, and I also have some sympathy for the idea that there could be huge-time-scale teleology associated with evolution that we cannot discern.
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