Reg_Prescott » April 20th, 2019, 3:09 am wrote:Depending on how fitness is defined, all talk of "survival of the fittest" -- natural selection in a nutshell -- expresses either a flat-out vacuous truism ("the survivors survive"),
That is not natural selection in a nutshell, at all.
This is what the
Theory of Evolution by Natural Selection looks like in a nutshell.
:: In a population of reproducing entities that contain variation, under certain conditions that variation will increase. In rare conditions, the variation will increase so much that speciation occurs. :: The occurrence of speciation is not a guarantee. The theory only claims that it does occur in some situations. The crucial claim the theory makes about the world is what is written between the double semicolons. I am using "crucial claim" in a highly technical sense here, as it usually appears in grand theories of physics.
or if one attempts to escape the circularity by endorsing a propensity interpretation of fitness, it tends towards a vacuous truism.
.. or one could attempt to escape this circularity by stating the actual theory.
The latter case is exactly analogous to "the casino wins" or "those who have what it takes to survive and reproduce will tend to survive and reproduce"; not true in every individual case (sometimes these purple-haired grannies get lucky, and sometimes an Adonis-like pre-pubescent lion gets struck by lightning), yet cannot fail to be true given a long enough time and large enough numbers.
The rest of this is based off a mischaracterisation of the theory, so I won't respond to it.
In both cases, the writer of the text is absolutely right: these are mathematical or linguistic "truisms" that "cannot be subverted" (his/her own words).
So what, you might retort?
1. One does not need to leave one's armchair to establish the truth of a truism. Why, then, do I keep hearing that natural selection is an empirical theory that has survived test after test? That which cannot be subverted does not need to be tested.
You have lost track of the conversation you started with an unknown conversant on an unknown forum. The claim made by that nameless person on far-away forum was that the english word "Selection" does not imply a conscious act of discrimination by a Selector Entity. The anonymous person claimed that mathematics or statistics is doing the selection of traits seen in extant species. If the anonymous poster claimed such, then I agree with him. As I said above the english word "selection" is standing in for a complex statistical process.
2. A truism explains precisely nothing. (cf. "Why is Peter a bachelor?" Ans "Because all bachelors are unmarried men") Why, then, do I keep hearing of the prodigious explanatory power of natural selection theory?
Statistical processes are truisms, yes.
However, as I wrote above, Natural Selection makes a claim about states-of-affairs in the world. That claim is testable. This is why it is a theory and why it requires experimental corroboration.