Hi! As someone passionately interested in Darwin and evolution (fairly topical!), I've become a bit perturbed by the objection that 'survival of the fittest' is a non-scientific idea. I've read in various places that it is a tautology, and therefore meaningless and 'devoid of explanatory power': since 'fittest' means 'most capable of surviving', it means 'survival of those most capable of surviving', or even 'survival of those that survive'. In the same way that 'all tables are tables' is circular reasoning, does this pose a serious challenge?

I find the points made in this webpage slightly scary: http://members.iinet.net.au/~sejones/PoE/pe02phl3.html

(They do seem to refute the answers given on the TalkOrigins evolution site.)

Please could you save me from my quandary? Thanks!

Semantic arguments based on a generalised summary of a theory are not robust criticisms of the theory. Natural selection is not "survival of the fittest" (Wallace's popular description of the process, not Darwin's), but the mechanism whereby survival of a cohort to the point of reproduction is influenced by natural processes that favour some variants over others.

Soundbites, summaries and generalisations do not a theory make, so refutations based on them are redundant.

Additionally, even when considered in a general form, natural selection conforms more closely to a feedback loop than a circularity, since each permutation of the loop is influenced by the previous permutation and by variations in the conditions that define "fitness".

I agree with Paolo - "survival of the fittest" is a catchy tag, but think of it as a tabloid headline designed to grab your attention rather than the whole story. As a tagline it is not a great descriptor of selection in my view. For example, it misses the key point that differences in survival are caused by variation in other traits (or genes). It also misses the point that selection is as much about reproduction as it is about survival (note that fitness and survival are NOT equivalent concepts). However, as a cachy soundbite I have to admit that "survival of the fittest" has caught, and stayed in,  the public imagnation.

As tags go, it's not a *bad* one, I actually rather like it. However, it is rather judging a book by it's cover (or title) - you have to read the details to get the most out of it and of course read the arguments for and against any given aspect.

"Survival of the fittest" (a phrase actually introduced by the philosopher Herbert Spencer, not by Wallace) may be just a soundbite, but I think there is nevertheless a substantive issue here. At least historically, some evolutionary biologists really did define an individual's fitness as the number of viable offspring it produced, while simultaneously claiming that differences in "fitness" were the cause of differences in reproductive success. Described this way, natural selection does indeed begin to sound tautological.

However, there is a way out of this conundrum. Once you have accepted the proposition that the fittest organisms will survive, you can go ahead and use number of viable offspring as a proxy for fitness. But if you are still at the stage of wanting to TEST that proposition, you need to define fitness in terms of traits that help an organism cope with the challenges of its environment and ecological niche. For example, cheetahs rely on sprinting ability to capture their prey, so it stands to reason that a faster cheetah would be more successful (would produce more viable offspring, on average) than a slower one. If you then go out and measure the top sprinting speed of lots of individual cheetahs, track them over the course of their lives, and confirm that the faster ones are indeed more successful, you have confirmed survival of the fittest in the case of cheetahs - although of course, traits other than running speed would certainly complicate this picture in reality.

Another way of showing that "survival of the fittest" is not a tautology is to consider alternative possibilities. In principle, you can imagine in world in which there was no meaningful genetic variation among animals within a given species, or a world in which variations existed but the environment was so wildly unstable that the variations were of no consequence for survival and reproductive success. In either of these cases, "survival of the fittest" would be meaningless because survival would be essentially random. When biologists talk about "survival of the fittest", they are implicitly claiming that differences exist within species, and that these differences can have a substantial impact on success - a statement with real, empirical content that scientists can sink their teeth into.

Thanks Corwin, I knew it wasn't Darwin's term, so I assumed it was one of Wallace's well-turned phrases... remiss of me!

The fact remains that irrespective of past misuse, "survival of the fittest" is just a metaphor - not a formulation of evolutionary theory. Perhaps biologists would be better off not using the phrase, to avoid misunderstandings?

I wouldn't entirely agree that "survival of the fittest" is just a metaphor - as I tried to show in the last paragraph of my previous post, I think it's more accurately described as a quick catchphrase that nevertheless sums up one important aspect of the evolutionary process, the idea that there is a struggle for existence in which individuals with genetic advantages tend to survive and reproduce. It's a bit like "for every action there is an equal and opposite reaction" as a statement of Newton's 3rd law of motion, a pithy verbal formula that can be used to vividly package an idea for the benefit of non-scientists.

Accordingly, I think biologists should continue to use the phrase, although I think we also need to get across the idea that "the fittest" are fundamentally defined as those with advantageous traits, rather than those that happen to have the most viable offspring at the end of the day.

For most people "fitness" means relates to an ability to run long distances or undertake strenuous activity. When discussing "fitness" with the lay-person I frequently encounter a breakdown in understanding between "fitness for purpose" and "fitness of constitution". We make assumptions about public understanding all the time and those assumptions can frequently lead to greater depths of misunderstanding. Ambiguity, coupled with the fact that the statement only addresses one aspect of evolution, but is commonly used to summarise the entire concept, makes me wary of using it.