<div dir="ltr"><div>Dear Dog Pile, </div><div><br></div><div>All nick ever said was that we have to mind our words, and that when words like selection and fitness get used in a technical context, the argument may go astray because of surplus meanings of the constructs being used. He would like to add that paying attention to the words (examining the metaphors) rigorously often has a heuristic value. He even provided a paper which (he thought) exemplified that principle. He would never argue against studying differences between women who had 3 children survive to adulthood and women who had, say, none. But he would be VERY careful what he called such research. Some have called Darwinian Psychology. What is NOT is evolutionary psychology, because evolutionary psychology was based on the concept of the Environment of Evolutionary Adaptedness, the idea that there was a time by (or for) which our current behavioral performances were designed. Therefore, knowing the conditions of Pleistocene life could warrant predictions about how human beings would behave today, whether or not those behaviors actually resulted in greater reproductive success now. The concept of design, implicit in Cosmides and Tooby's manifesto of Evolutionary Psycholgoy, has been overlooked by many of their followers, but it is central to that project. When eliminated the research becomes like DES's 2a and 2b ( or not "Tooby") in that it tells us only some other features of the winners other than that they won. Each of these constitutes a hunch about why they won, of course. But it relates only distantly to Darwin's hunch that there is some higher-order property of sucessful organisms which, if we knew it, could predict their success. </div><div><br></div><div>Nick</div><div><br></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Tue, Mar 31, 2026 at 2:16\u202fPM Santafe <<a href="mailto:desmith@santafe.edu">desmith@santafe.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi EricC<br>
<br>
I will drop out of this soon because of time conflicts. But an edit or two below:<br>
<br>
> On Mar 31, 2026, at 15:47, Eric Charles <<a href="mailto:eric.phillip.charles@gmail.com" target="_blank">eric.phillip.charles@gmail.com</a>> wrote:<br>
> <br>
> I'll also note that "function" can't do the work on its own to explain evolution. We still need to know why some functions are favored by selection and others are not. EricS seemed to indicate that we assess "fit" by determining if animals are "happy"\u2026.<br>
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In this case, no. Exactly not that. The long tedious first post from me was an objection to vague gestures at what \u201cfit\u201d means, using \u201chappy\u201d as an example of vagueness. The aim in the passage was to explain the role of Fisher\u2019s supplying specific constructions of summary statistics defined on instances of population processes. <br>
<br>
Not to say that we have to do things Fisher\u2019s way; I had other comments on that question. Rather, to say that one doesn\u2019t generate a tautology by first providing a definition of what quantity you are pulling from data, to which you are trying to fit a regression model.<br>
<br>
> but the metaphor of "fit" is like a key in a lock. To explain evolution you need the matching of form-and-function-to-a-particular-environment. That matching *sometimes* increases reproductive success, and *sometimes* the traits in question are hereditary. <br>
<br>
All the sometimeses and hedges are certainly right. I didn\u2019t belabor them. But for sure, if one writes regression models, it is because there is supposed to be data scatter that the model isn\u2019t trying to account for. Also the other comments here and there in the threads about all the things that one or another regression model will leave out; where they go in a Price equation decomposition, and the question of whether your regression model falls apart when some formerly-unconsidered dummy variables are added.<br>
<br>
<br>
I didn\u2019t end up saying as much about flavor text in these threads as I guess the main thread would have motivated. I guess that is because I got sidetracked on trying to provide language for an account of what geneticists and others are doing, behind the various human-language terms, since it wasn\u2019t clear to me that all that was familiar.<br>
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> Population genetics combined with field research can be very powerful along those lines, but the math of population genetics on its own, floating out in the ether, can't do it at all. <br>
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Again, yes. Both of the last two replies to Nick today were meant to say something specific about those limitations.<br>
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There is _much_ more that can be said. A regression model at all is, only in a _very_ generous widening of the notion of \u201ccausation\u201d, a \u201ccausal model\u201d. But I have comments littered here and there in the messy posts about how other domains in functional biology go after those other forms of descriptions.<br>
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Anyway, I agree with you; time for me to stop. I will hope that in there, there was some commentary on extant practice that Nick will at some point find useful.<br>
<br>
Eric<br>
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</blockquote></div><div><br clear="all"></div><br><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div>Nicholas S. Thompson</div><div>Emeritus Professor of Psychology and Ethology</div><div>Clark University</div><div><a href="mailto:nthompson@clarku.edu" target="_blank">nthompson@clarku.edu</a></div><div><a href="https://wordpress.clarku.edu/nthompson" target="_blank">https://wordpress.clarku.edu/nthompson</a></div><div><a href="https://substack.com/@monist" target="_blank">https://substack.com/@monist</a></div></div></div>