| → natural 1859 1860 1861 1866 1869 |
| variation and natural 1872 |
|
| → gradations in the perfection of any organ or instinct, which we may consider, either do now exist or could have existed, each good of its kind,— that all organs 1859 |
| gradations in the perfection of any organ or instinct which we may consider, either do now exist or could have existed, each good of its kind,— that all organs 1860 |
| all organs 1861 1866 |
| all parts of the organisation 1869 1872 |
|
| → are, in ever so slight a degree, variable,— and, lastly, 1859 1860 |
| are, in ever so slight a degree, variable— 1861 1866 |
| offer, at least, individual differences— 1869 1872 |
|
| → instinct. 1859 1860 |
| instinct— and, lastly, that gradations in the perfection of every organ may have existed, each good of its kind. 1861 1866 |
| instinct— and, lastly, that gradations in the state of perfection of each organ may have existed, each good of its kind. 1869 1872 |
|
|
CHAPTER
|
| RECAPITULATION AND CONCLUSION. |
| Recapitulation of the
the theory of Natural Selection— Recapitulation of the general and special circumstances in its
Causes of the general belief in the immutability of species— How far the theory of
may be extended— Effects of its adoption on the study of Natural
Concluding remarks. |
|
this whole volume is one long argument, it may be convenient to the reader to have the leading facts and inferences briefly recapitulated. |
|
| That many and
objections may be advanced against the theory of descent with modification through
→natural
selection, I do not deny. I have endeavoured to give to them their full force. Nothing at first can appear more difficult to believe than that the more complex organs and instincts
have been perfected, not by means superior to, though analogous with, human reason, but by the accumulation of innumerable slight variations, each good for the individual possessor. Nevertheless, this difficulty, though appearing to our imagination insuperably great, cannot be considered real if we admit the following propositions,
that
→gradations in the perfection of any organ or instinct, which we may consider, either do now exist or could have existed, each good of its kind,— that all organs
and instincts
→are, in ever so slight a degree, variable,— and, lastly,
that there is a struggle for existence leading to the preservation of
profitable
of structure or
→instinct. The truth of these propositions cannot, I think, be disputed.
|
