It seems that it is almost as easy to come up with a Natural Selection story which would explain why a bird in a certain environment would move slowly, stealthily, and be have feathers that are a similar color as the ground as it is to explain why a bird moves quickly, calls loudly, and is brightly colored. It seems that the ability to explain animal behavior and physical characteristics using Natural Selection is in large part up to the creativity of the person doing the explaining.
Natural selection doesn’t explain why or predict that a bird might have detrimental traits such as bright coloring that can betray it to predators. Darwin invented a whole other selective mechanism to explain the appearance of such traits—sexual selection, later elaborated into the Handicap principle. Sexually selected traits are necessarily historically contingent, but you can’t just explain away any hereditary handicap as a product of sexual selection: the theory makes the nontrivial prediction that mate selection will depend on such traits.
For an analogy, consider the fact that mathematicians also find it useful to distinguish between “squares” and “rectangles”—but they nevertheless correctly insist that all squares are in fact rectangles.
The problem here isn’t that “sexual selection” isn’t a useful concept on its own; the problem is the failure to appreciate how abstract the concept of “natural selection” is.
I have a similar feeling, ultimately, about the opposition between “natural selection” and “artificial selection”, even though that contrast is perhaps more pedagogically useful.
The problem here isn’t that “sexual selection” isn’t a useful concept on its own; the problem is the failure to appreciate how abstract the concept of “natural selection” is.
I think there’s a substantive dispute here, not merely semantics. The original complaint was that Natural Selection was an unconstrained theory; the point of my comment was that in specific cases, the actual operating selective mechanisms obey specific constraints. The more abstract a concept is (in OO terms, the higher in the class hierarchy), the less constraints it obeys. Saying that natural selection is an abstract concept that encompasses a variety of specific mechanisms is all well and good, but you can’t instantiate an abstract class.
Sexually selected traits are necessarily historically contingent, but you can’t just explain away any hereditary handicap as a product of sexual selection: the theory makes the nontrivial prediction that mate selection will depend on such traits.
Hmm. Generalization: a theory that concentrates probability mass in a high-dimensional space might not do so in a lower-dimensional projection. This seems important, but maybe only because I find false claims of nonfalsifiability/lack of predictive power very annoying.
I’m having trouble seeing the relation between your comment and mine, but I’m intrigued and wish to subscribe to your newsletter would like to see it spelled out a bit.
Birds, which fly, or which descend from birds who flew, are often brighly colored. Animals that don’t fly are seldom brightly colored. A major exception is animals or insects that are poisonous. Natural selection handles this pretty well.
Do you have any examples in mind? It seems to me that only a misunderstanding of natural selection could explain fake animal behavior.
It seems that it is almost as easy to come up with a Natural Selection story which would explain why a bird in a certain environment would move slowly, stealthily, and be have feathers that are a similar color as the ground as it is to explain why a bird moves quickly, calls loudly, and is brightly colored. It seems that the ability to explain animal behavior and physical characteristics using Natural Selection is in large part up to the creativity of the person doing the explaining.
Natural selection doesn’t explain why or predict that a bird might have detrimental traits such as bright coloring that can betray it to predators. Darwin invented a whole other selective mechanism to explain the appearance of such traits—sexual selection, later elaborated into the Handicap principle. Sexually selected traits are necessarily historically contingent, but you can’t just explain away any hereditary handicap as a product of sexual selection: the theory makes the nontrivial prediction that mate selection will depend on such traits.
Sexual selection is just a type of natural selection, not a different mechanism. Just look at genes and be done with it.
I wish I could upvote this comment twice.
Why? I didn’t really feel like trying to win over Michael Vassar, but since you feel so strongly about it, I should point out that biologists do find it useful to distinguish between “ecological selection” and “sexual selection”.
For an analogy, consider the fact that mathematicians also find it useful to distinguish between “squares” and “rectangles”—but they nevertheless correctly insist that all squares are in fact rectangles.
The problem here isn’t that “sexual selection” isn’t a useful concept on its own; the problem is the failure to appreciate how abstract the concept of “natural selection” is.
I have a similar feeling, ultimately, about the opposition between “natural selection” and “artificial selection”, even though that contrast is perhaps more pedagogically useful.
I think there’s a substantive dispute here, not merely semantics. The original complaint was that Natural Selection was an unconstrained theory; the point of my comment was that in specific cases, the actual operating selective mechanisms obey specific constraints. The more abstract a concept is (in OO terms, the higher in the class hierarchy), the less constraints it obeys. Saying that natural selection is an abstract concept that encompasses a variety of specific mechanisms is all well and good, but you can’t instantiate an abstract class.
Hmm. Generalization: a theory that concentrates probability mass in a high-dimensional space might not do so in a lower-dimensional projection. This seems important, but maybe only because I find false claims of nonfalsifiability/lack of predictive power very annoying.
I’m having trouble seeing the relation between your comment and mine, but I’m intrigued and
wish to subscribe to your newsletterwould like to see it spelled out a bit.Birds, which fly, or which descend from birds who flew, are often brighly colored. Animals that don’t fly are seldom brightly colored. A major exception is animals or insects that are poisonous. Natural selection handles this pretty well.