"But you ignored an important part of your own quote , `` Thus , without an independent criterion for fitness , other than survival , ... `` And of course , Darwin did most certainly express other criterion besides survival . Let me help clarify for you . Survival is not the sole requirement , or even the most important requirement . It should be quite clear to even the most muddled thinker that reproduction is required . In fact , reproduction is the most important requirement . Survival is necessary only long enough for an organism to reproduce , and if an organism does n't reproduce , it is an evolutionary dead end no matter how long it survives . You see , as was mentioned in your definitions and in comments , natural selection is differential reproduction . Natural selection is not a tautology . Only the phrase , `` survival of the fittest `` reduces to a tautology ."
"Which , as stated , Darwin thought was in fact a better phrase , or 'more accurate ' ... `` But the expression often used by Mr. Herbert Spencer , of the Survival of the Fittest , is more accurate , and is sometimes equally convenient. `` from the 6th edition of `` Origin of the Species `` http : //www.literature.org/authors/da ... hapter-03.html"
"Thus , without an independent criterion for fitness , other than survival"
"expression often used by Mr. Herbert Spencer , of the Survival of the Fittest"