« НазадПродовжити »
“But with regard to the material world, we can at least go so far as this—we can perceive that events are brought about not by insulated interpositions of Divine power, exerted in each particular case, but by the establishment of general laws."
W. WHEWELL: Bridgewater Treatise.
“ To conclude, therefore, let no man out of a weak conceit of sobriety, or an ill-applied moderation, think or maintain, that a man can search too far or be too well studied in the book of God's word, or in the book of God's works; divinity or philosophy; but rather let men endeavour an endless progress or proficience in both."
Bacon: Advancement of Learning.
“The only distinct meaning of the word 'natural' is stated, fixed, or settled; since what is natural as much requires and presupposes an intelligent agent to render it so, é. e. to effect it continually or at stated times, as what is supernatural or miraculous does to effect it for once."
BUTLER: Analogy of Revealed Religion.
Doron, Bromley, Kent,
October 1st, 1869.
PRESERVATION OF FAVOURED RACES IN THE STRUGGLE
CHARLES DARWIN, M.A.,
FELLOW OF THE ROYAL, GEOLOGICAL, LINNEAN, ETC., SOCIETIES ;
4 NEW EDITION, REVISED AND AUGMENTED BY THE AUTHOR,
443 & 445 BROADWAY.
CONTRIBUTED BY THE AUTHOR TO THIS AMERICAN EDITION.
I WILL here attempt to give a brief, but I fear imper. fect, sketch of the progress of opinion on the Origin of Specie The great majority of naturalists have believed that species were immutable productions and have been separately created : this view has been ably maintained by many authors. A few naturalists, and several who have not particularly studied natural history, believe, on the other hand, that species undergo modification, and that the existing forms of life have descended by true generation from pre-existing forms. Passing over anthors of the classical period, and likewise Demaillet and Buffon, with whose writings I am not familiar, Lamarck was the first man, whose view that species undergo change excited much attention. This justly celebrated naturalist published his Philosophie Zoologique in 1809, and his Introduction to his Hist. Nat. des animaux sans Vertèbres in 1815, in which works he upholds the doctrine that species are descended from each other. He seems to have been chiefly led to this conclusion by the difficulty of distinguishing species and varieties,—by the almost perfect gradation of the forms in certain groups, and by the analogy of domestic productions. With respect to the means of modification, he attributed something to the action of external conditions, something to the crossing of already existing forms, and much to use and disuse or the effects of habit. To this latter agency he seems to attribute all the beautiful adaptations in nature,—such as the long neck of the giraffe for browsing on the branches of trees.* But he likewise believed in a law of progressive development; and as all the forms of life thus tended to progress, in order to account for the presence of very simple productions at the present day, he maintained that such forms were now spontaneously generated.
Geoffroy Saint Hilaire, as is stated in his Life by his Son, as early as 1795, suspected that what we call species are various degenerations of the same type. It was not until 1828 that he published his conviction that the same forms have not been perpetuated since the origin of all things. Geoffroy seems to have relied chiefly on the conditions of life, or the “monde ambiant," as the cause of change ; but he was cautious, and, as his son says, “C'est donc un problème à reserver entièrement a l'avenir, supposé même que l'avenir doive avoir prise sur lui.”
In England, the Hon. and Rev. W. Herbert, afterwards Dean of Manchester, in his work on the Amaryllidaceæ (1837, p. 19, 339), declares that “horticultural experiments have established, beyond the possibility of refutation, that botanical species are only a higher and more permanent class of varieties." He extends the same view to animals. The Dean believes that single species of each genus were created in an originally highly plastic condition, and that these by intercrossing and by variation have produced all our existing species.
* It is curious how completely my grandfather, Dr. Erasmus Darwin, anticipated these erroneous views in his Zoonomia (vol. i. pp. 500-510), pube lished in 1794.