They will transmit their superior size, or swiftness, or better color, or whatever superiority they possess, to their offspring.

The process will go on in successive generations, each adding an infinitesimal quantity to the stock gained by the past generation; just as breeders of improved stock increase the weight of cattle by breeding from the largest; or breeders of race-horses increase the speed by breeding from the swiftest.

In this way varieties from the same family will grow into different species.
And, as only those differences which are beneficial to the animal are preserved, they will grow into improved species; and, as variations of all sorts take place, so all sorts of varieties and species arise in process of time.

All will thus tend to perfect themselves according to the laws of nature, and without any special oversight or care of God, or of anybody but Natural Selection; which Mr.Darwin takes special care to describe as an unintelligent selector.

He defines the nature which selects to be "the aggregate action and product of natural laws," and these laws are "the sequences of events as ascertained by us." He ridicules the idea of God's special endowment of the fantail pigeon with additional feathers, or of the bull dog's jaws with strength, and says, "But if we give up the principle in the one case, if we do not admit that the variations of the primeval dog were intentionally guided in order, for instance, that the greyhound, that perfect image of symmetry and vigor, might be formed; no shadow of reason can be assigned for the belief that variations alike in nature, and the results of the same general laws which have been the groundwork through Natural Selection of the most perfectly adapted animals in the world, man included, were intentionally and specially guided."[9] This, then, is the grand distinctive difference of Mr.Darwin's mode of producing the various animals; namely, that it is unintelligent, their variations are not designed nor intended by the Creator, but they are the results of a method of trial and error, producing a hit-and-miss pattern.