Perhaps so. Darwin may not have coined the phrase, though he apparently regarded it as felicitous enough in capturing his theory of natural selection as to incorporate it himself in later writings.
These claims are not historically accurate. Just because the phrase "survival of the fittest" accidentally appears in the writing of Darwin somewhere, does not entail that he thought it was
"felicitous in capturing the theory's definition {sic}"Reg_Prescott » April 23rd, 2019, 1:58 pm wrote:As for how natural selection ought to be characterised, I quote the following from the Stanford Encyclopedia of Philosophy:
(and as for those who can't recall natural selection being referred to as a "theory", a quick google search might do the trick. Prepare for a deluge!)
"Natural selection is a causal process. Distinguishing it from other processes in evolution is one of major conceptual and empirical problems of evolutionary biology. The bare bones of Darwin's theory of evolution by natural selection are elegantly simple. Typically (but not necessarily) there is variation among organisms within a reproducing population. Oftentimes (but not always) this variation is (to some degree) heritable. When this variation is causally connected to differential ability to survive and reproduce, differential reproduction will probably ensue. This last claim is one way of stating the Principle of Natural Selection (from here on PNS). The PNS goes beyond the causally neutral statement that is sometimes listed as the third of what are often called “Darwin's Three Conditions”, viz., different variants sometimes reproduce at different rates. That statement leaves open the question of whether or not the variation in question is causally responsible for the differential reproduction. It leaves open the question of whether a qualitatively similar outcome would result from repeated iterations of this set-up. It leaves open the question of whether this process is natural selection or drift (see below). It—the causally neutral statement—does not suffice to state Darwin's causal theory. Darwin clearly recognized this (see, for example 1871) as did Lewontin (1978); although many contemporary commentators fail to see this.
Why is it that some variants leave more offspring than others? In those cases we label natural selection, it is because those variants are better adapted, or are fitter than their competitors. Thus we can define natural selection as follows: Natural selection is differential reproduction due to differential fitness (or differential adaptedness) within a common selective environment (see next section). This definition makes the concept of natural selection dependent on that of fitness, which is unfortunate since many philosophers find the concept of fitness deeply mysterious (see e.g., Ariew and Lewontin 2004). But like it or not, that is the way the theory is structured. And, fortunately, we can make considerable headway in understanding natural selection without solving all of the philosophical problems surrounding the concept of fitness."
I've highlighted the critical section in bold.
"Natural selection is differential reproduction due to differential fitness". In other words, the more fit reproduce more successfully than the less fit.
But who exactly are the more fit? If the answer is "those who reproduce more successfully" then we have an obvious tautology, i.e., "those who reproduce more successfully do so more successfully than those who reproduce less successfully".
This is the source of the tautology problem, and this is why a propensity interpretation of fitness has been suggested. But as noted above, it seems to me the propensity interpretation helps little if at all in escaping the circularity.
These are perfectly fine criticisms of the text portions you have quoted. Your dismissal of the "Propensity Definition" of Mills and Beaty is also well-stated. Unfortunately, you are no longer talking to us here on the forum. Instead you are just debating characters who are not present on this forum using us as a proxy.
I feel no responsibility to defend these people you are quoting, I would go farther and even disagree with them on key premises and disagree with their conclusions too.
If I met the writer of the above quote, or Mills, or Betty, I would tell them what we know in 2019 about evolutionary dynamics.
We have simulated evolution on computers, and it works faithfully to the theory. Early uses of
Genetic Algorithms were primarily concerned with optimization. However, those of us at GECCO conferences are aware that the process of evolution is not particularly concerned with driving the population towards an optimum. There are numerous interesting, funny and dramatic stories about how we are let down by Genetic Algorithms "misbehaving" on us. (I could go on all night relaying these stories to the forum.)
In the context of this conversation, there is absolutely nothing about evolution that suggests there is some primrose path that walks living forms up a Great-Chain-of-Being to higher and better forms. If Charles Darwin and Alfred Wallace believed this, that's fine. They were mistaken, and likely bewitched by Victorian attitudes of their time and place in England.
Perhaps the use of GAs as optimizers was an attempt to make it "legitimate" in the engineering and science fields. Genetic Algorithms can be set up to produce and refine optimal candidate solutions -- yes -- But everyone at GECCO knows this does not go on in the wild.
(I am going to make a hefty syllogism, so keep up with my tortured english.)
IF the claim is that evolution drives a population directly towards an optimum is the "Incredulity Test" or the "Smell Test" of genetic algorithms ....
THEN Berlinski's assertion that GAs do not rise to an explanatory theory the likes of gravity-and-solar-system theory does, is sound. They do not pass the Smell Test. Incredulity is warranted.
Newtonian-Gravity-Solar-system theory. The measured behavior of the planets nearly maps one-to-one with the predictions of the theory on the chalkboard. Ergo is passes the Smell Test. A Berlinski says it, gravity "rises to the challenge of a predictive theory".
Genetic Algorithms do not always work well. They can fail. Ecosystem simulations can run on a workstation in the corner of an office for over 2 months without stopping. They can also go extinct after several days. My personal interaction with them shows that they are far more likely to keep going than to be found extinct. Extinctions are usually a sign that you have set something wrong in the parameters. ("Something wrong" in the parameters can even be e.g. the density of organisms is too low compared to the size of the environment.) There is no science behind these things. It's still somewhat of a black art.
As any textbook on GAs will show you, there are also anecdotes that are equally dramatic and interesting where a GA performed far beyond anyone's expectations.
(If I may relate one of them.) A mathematician declared he had found the optimum of a batcher sort of 30 items. Then a computer scientist used a GA and found one better than the "optimal" sorter already published. The computer scientist declared that
his sorter was optimal. Decades later, another scientist used a different GA and found one even better. At this point, nobody was going to cry wolf a third time, and premature claims of "optimality" are completely missing from the paper.
There are situations where a GA came up with something that is far better than anything designed by a human engineer -- and the solution uses techniques never considered by human scientists.
So it's a mixed bag. If I could meet Mills and Beaty, I woudl tell them that our current understanding of evolution in 2019, is that evolution is a description of a
Complex Adaptive System.http://wiki.cas-group.net/index.php?title=Complex_Adaptive_SystemCASs are finicky, prone to failure, sometimes exhibit extreme success. They are highly sensitive to initial conditions, difficult to control and most of their statistical properties have to be described using Chaos Theory.
We simulate evolution for the same reasons we simulate weather and high-temperature plasmas. There is no closed-form solution to their dynamics.
It seems to me this harping away at fitness is really driven by a human desire to try to describe the complex dynamics of evolution using some obvious, one-sentence catch-all mechanism. Some local and simple like "domino A knocks over domino B." A chain of dominoes falling then constitutes "the process". It's the intellectual equivalent of trying to describe the Stock Market as "people sell stuff, and others buy stuff." In our context of this thread it is
"the fittest survive". It's local, easy-to-understand, punctual and clicky.
But is woefully wrong.
The reality is that no such catch-all sentence exists, because evolution, strictly speaking, is a long-term process over several million or billion cycles of reproduction. The kind of guarantees delivered by Gravity-Moves-Planets-In-Orbits is not found here.
http://gecco-2018.sigevo.org/index.html/tiki-index.php?page=Accepted%20Papers
