It is an error to imagine that evolution signifies a constant tendency to increased perfection. That process undoubtedly involves a constant remodeling of the organism in adaptation to new conditions; but it depends on the nature of those conditions whether the direction of the modifications effected shall be upward or downward.
But I think that in the repeated and almost entire changes of organic types in the successive formations of the earth—in the absence of mammalia in the older, and their very rare appearance (and then in forms entirely. unknown to us) in the newer secondary groups—in the diffusion of warm-blooded quadrupeds (frequently of unknown genera) through the older tertiary systems—in their great abundance (and frequently of known genera) in the upper portions of the same series—and, lastly, in the recent appearance of man on the surface of the earth (now universally admitted—in one word, from all these facts combined, we have a series of proofs the most emphatic and convincing,—that the existing order of nature is not the last of an uninterrupted succession of mere physical events derived from laws now in daily operation: but on the contrary, that the approach to the present system of things has been gradual, and that there has been a progressive development of organic structure subservient to the purposes of life.
Nov.r 24 1859
My dear Darwin
I write to thank you for your work on the origin of Species. It came, I think, in the latter part of last week; but it may have come a few days sooner, & been overlooked among my bookparcels, which often remain unopened when I am lazy, or busy with any work before me. So soon as I opened it I began to read it, & I finished it, after many interruptions, on tuesday. Yesterday I was employed 1st. in preparing for my lecture—2dly. In attending a meeting of my brother Fellows to discuss the final propositions of the Parliamentary Commissions. 3d. In lecturing 4thly.In hearing the conclusion of the discussion & the College reply whereby in conformity with my own wishes we accepted the scheme of the Commission 5th. in Dining with an old friend at Clare College— 6thly In adjourning to the weekly meeting of the Ray Club, from which I returned at 10. P.M.—dog-tired & hardly able to climb my staircase— Lastly in looking thro’ the Times to see what was going on in the busy world—
I do not state this to fill space (tho’ I believe that Nature does abhor a vacuum); but to prove that my reply & my thanks are sent to you by the earliest leisure I have; tho’ this is but a very contracted opportunity.— If I did not think you a good tempered & truth loving man I should not tell you that, (spite of the great knowledge; store of facts; capital views of the corelations of the various parts of organic nature; admirable hints about the diffusions, thro’ wide regions, of nearly related organic beings; &c &c) I have read your book with more pain than pleasure. Parts of it I admired greatly; parts I laughed at till my sides were almost sore; other parts I read with absolute sorrow; because I think them utterly false & grievously mischievous—You have deserted—after a start in that tram-road of all solid physical truth—the the true method of induction—& started up a machinery as wild I think as Bishop Wilkin’s locomotive that was to sail with us to the Moon. Many of your wide conclusions are based upon assumptions which can neither be proved nor disproved. Why then express them in the language & arrangements of philosophical induction?.—
As to your grand principle—natural selection—what is it but a secondary consequence of supposed, or known, primary facts. Development is a better word because more close to the cause of the fact. For you do not deny causation. I call (in the abstract) causation the will of God: & I can prove that He acts for the good of His creatures. He also acts by laws which we can study & comprehend— Acting by law, & under what is called final cause, comprehends, I think, your whole principle. You write of “natural selection” as if it were done consciously by the selecting agent. ‘Tis but a consequence of the presupposed development, & the subsequent battle for life.—
This view of nature you have stated admirably; tho’ admitted by all naturalists & denied by no one of common sense. We all admit development as a fact of history; but how came it about? Here, in language, & still more in logic, we are point blank at issue— There is a moral or metaphysical part of nature as well as a physical A man who denies this is deep in the mire of folly Tis the crown & glory of organic science that it does thro’ final cause , link material to moral; & yet does notallow us to mingle them in our first conception of laws, & our classification of such laws whether we consider one side of nature or the other— You have ignored this link; &, if I do not mistake your meaning, you have done your best in one or two pregnant cases to break it. Were it possible (which thank God it is not) to break it, humanity in my mind, would suffer a damage that might brutalize it—& sink the human race into a lower grade of degradation than any into which it has fallen since its written records tell us of its history. Take the case of the bee cells. If your development produced the successive modification of the bee & its cells (which no mortal can prove) final cause would stand good as the directing cause under which the successive generations acted & gradually improved— Passages in your book, like that to which I have alluded (& there are others almost as bad) greatly shocked my moral taste. I think in speculating upon organic descent, you over state the evidence of geology; & that you under state it while you are talking of the broken links of your natural pedigree: but my paper is nearly done, & I must go to my lecture room—
Lastly then, I greatly dislike the concluding chapter—not as a summary—for in that light it appears good—but I dislike it from the tone of triumphant confidence in which you appeal to the rising generation (in a tone I condemned in the author of the Vestiges), & prophesy of things not yet in the womb of time; nor, (if we are to trust the accumulated experience of human sense & the inferences of its logic) ever likely to be found any where but in the fertile womb of man’s imagination.—
And now to say a word about a son of a monkey & an old friend of yours. I am better, far better than I was last year. I have been lecturing three days a week (formerly I gave six a week) without much fatigue but I find, by the loss of activity & memory, & of all productive powers, that my bodily frame is sinking slowly towards the earth. But I have visions of the future. They are as much a part of myself as my stomach & my heart; & tho visions are to have their antitype in solid fruition of what is best & greatest But on one condition only—that I humbly accept God’s revelation of himself both in His works & in His word; & do my best to act in conformity with that knowledge which He only can give me, & He only can sustain me in doing If you & I do all this we shall meet in heaven
I have written in a hurry & in a spirit of brotherly love. Therefore forgive any sentence you happen to dislike; & believe me, spite of our disagreement in some points of the deepest moral interest, your true-hearted old friend | A. Sedgwick.