"Not one change of species into another is on record . . we cannot prove that a single species has been changed."—Charles Darwin, My Life and Letters.
I think quote mining can be inherently dishonest, don't you think?
Quote #2.7
[Re: Evolution is a faith not based on evidence]
"When we descend to details we can prove that no one species has changed (i.e., we cannot prove that a single species has changed): nor can we prove that the supposed changes are beneficial, which is the groundwork of the theory. Nor can we explain why some species have changed and others have not. The latter case seems to me hardly more difficult to understand precisely and in detail than the former case of supposed change" - Darwin, 1863.
Representative quote miner: Treasures: Why Evolution!
First of all, the quote is from a "P.S." to a letter to G. Bentham, May 22, 1863 [Darwin, F., ed. 1905. The Life and Letters of Charles Darwin , Vol. 1. New York: D. Appleton & Co., p. 209-10].
As an aside, the main part of the letter is discussing, interestingly enough, the aspect of the fossil record that eventually lead to proposal of the theory of Punctuated Equilibria:
The objection . . . of certain forms remaining unaltered through long time and space, is no doubt formidable in appearance, and to a certain extent in reality according to my judgment. But does not the difficulty rest much on our silently assuming that we know more than we do? ... [I]n judging the theory of Natural Selection, which implies that a form will remain unaltered unless some alteration be to its benefit, is it so very wonderful that some forms should change much slower and much less, and some few should have changed not at all under conditions which to us (who really know nothing what are the important conditions) seem very different.
In essence, Darwin is saying that the stasis in the morphology of species found in the fossil record is partly due to the imperfection of the record itself and, possibly, partly due to differential rates of change in species. While Darwin's default position was for gradualistic change in species, such concepts are relative. He saw that some change in species could take much longer than others and, of course, the Punctuated Equilibria theorists only claim that change tends to come "rapidly" in geologic terms but over very long times in human terms.
Now to the actual quote:
P.S. -- In fact, the belief in Natural Selection must at present be grounded entirely on general considerations. (1) On its being a vera causa, from the struggle for existence; and the certain geological fact that species do somehow change. (2) From the analogy of change under domestication by man's selection. (3) And chiefly from this view connecting under an intelligible point of view a host of facts. When we descend to details, we can prove that no one species has changed [i.e. we cannot prove that a single species has changed]; nor can we prove that the supposed changes are beneficial, which is the groundwork of the theory. Nor can we explain why some species have changed and others have not. The latter case seems to me hardly more difficult to understand precisely and in detail than the former case of supposed change.Bronn may ask in vain, the old creationist school and the new school, why one mouse has longer ears than another mouse, and one plant more pointed leaves than another plant. . . . the fact that they have not been modified does not seem to me a difficulty of weight enough to shake a belief grounded on other arguments.
Here Darwin is pointing that Natural Selection can be seen to operate and serves as a single coherent explanation for many diverse phenomena. Even if all the details of the individual phenomena are not known, the "consilience", in William Whewell's phrase, of his mechanism cogently explaining a wide range of events is, itself, support for its status as a "vera causa". [See Snyder, Laura J., "William Whewell", The Stanford Encyclopedia of Philosophy (Spring 2004 Edition), Edward N. Zalta (ed.).] Add to that the fact that the fossil record generally shows change in life over time and the clear analogy from animal breeding, and there is substantial support for his proposed mechanism.
As to the quote mined portion, Darwin is saying that, based on the fossil record (the only evidence available at the time, before genetics), there wasn't enough detail to say that aparticular species was the descendant of a particular earlier species. By the same token, then, it would be impossible to show from the fossils that any particular species had changed into another. This is a "problem" with all fossil evidence, at least until and unless we can recover DNA or other genetic material. It constitutes some sort of refutation of evolution only to those who are determinedly hopeful of one and willfully ignorant.
The other point Darwin was making in the P.S. is that it is not necessarily possible to determine just what about a trait makes it advantageous, given the complexity of the interaction of the organism with the environment. In fact, Darwin is here warning against the "just so stories" that Stephen Jay Gould would inveigh against 120 years later. Once again, this is an excellent example of just how deeply and comprehensively Darwin understood his theory.
This quote mine is similar to Quote 82 but longer and without additional text (not from Darwin) that was included in Quote 82.
- John (catshark) Pieret