Try this with Natural Selection and you will find that it can explain just about any animal behavior, even fake animal behavior. What should be the take away lesson from this?
I didn’t understand Psychohistorian’s post as suggesting that we should make up fictional data—for then of course it may be no surprise that the given theory would have to bend in order to accommodate it. Rather, we should take real data, which is not explained by the theory (but which is understood in light of some different theory), and see just how easily the advocate can stretch his explanation to accommodate it. Does he/she notice the stretch? Can he/she resolve the difference between that data from the others?
What should be the take away lesson from this?
People get into man-with-a-hammer mode with evolutionary explanations. A lot. Because of the nature of evolutionary biology, sometimes they just reason like, “I can imagine what advantages this feature could have conferred in the past. Thus, …”. And yes, a lot of the time what you get is ad hoc crap.
But what if we don’t know which data is actually explained by the theory or not? That will make it hard to come up with “real data, which is not explained by the theory”.
Not quite. The idea is to see if the theory can convincingly explain fake data. If it can, it doesn’t mean the theory is wrong, it just means your capacity to infer things from it is limited. Natural selection is interesting and useful, but it is not a reliable predictor in many cases. You routinely see people say, “The market must do X because of Y.” If they could say basically the exact same thing about ~X, then it’s a fake explanation; their theory really doesn’t tell them what the market will do. If a theory can convincingly explain false data, you’ve got to be very cautious in using it to make predictions or claims about the world.
Conversely, theories with extremely high predictive power will consistently pass the test. If you used facts centered in physics or chemistry, a competent test-taker should always spot the false data, because our theories in physics and chemistry mostly have extremely precise predictive power.
That one ought not to attempt utterly unsupported natural-selection-based inferences in the domain of animal behavior but rather limit them to the domain of physical characteristics.
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.
Try this with Natural Selection and you will find that it can explain just about any animal behavior, even fake animal behavior. What should be the take away lesson from this?
I didn’t understand Psychohistorian’s post as suggesting that we should make up fictional data—for then of course it may be no surprise that the given theory would have to bend in order to accommodate it. Rather, we should take real data, which is not explained by the theory (but which is understood in light of some different theory), and see just how easily the advocate can stretch his explanation to accommodate it. Does he/she notice the stretch? Can he/she resolve the difference between that data from the others?
People get into man-with-a-hammer mode with evolutionary explanations. A lot. Because of the nature of evolutionary biology, sometimes they just reason like, “I can imagine what advantages this feature could have conferred in the past. Thus, …”. And yes, a lot of the time what you get is ad hoc crap.
But what if we don’t know which data is actually explained by the theory or not? That will make it hard to come up with “real data, which is not explained by the theory”.
Not quite. The idea is to see if the theory can convincingly explain fake data. If it can, it doesn’t mean the theory is wrong, it just means your capacity to infer things from it is limited. Natural selection is interesting and useful, but it is not a reliable predictor in many cases. You routinely see people say, “The market must do X because of Y.” If they could say basically the exact same thing about ~X, then it’s a fake explanation; their theory really doesn’t tell them what the market will do. If a theory can convincingly explain false data, you’ve got to be very cautious in using it to make predictions or claims about the world.
Conversely, theories with extremely high predictive power will consistently pass the test. If you used facts centered in physics or chemistry, a competent test-taker should always spot the false data, because our theories in physics and chemistry mostly have extremely precise predictive power.
That one ought not to attempt utterly unsupported natural-selection-based inferences in the domain of animal behavior but rather limit them to the domain of physical characteristics.
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.