Evolution in Modern Thought

In the case of the _green caterpillars with bright longitudinal stripes_, numerous individuals exhibiting this useful variation must have been produced to start with. In all hig...

Darwin next attempts to establish the _specific_ genealogical tree of man, and carefully weighs the differences and resemblances between the different families of the Primates....

In passing, certain other considerations may be referred to. First, that there are observations favouring the view that the production of totally sterile cross-breds is seldom a...

During this period nevertheless one distinct advance was made, that with which Weismann's name is prominently connected. In Darwin's genetic scheme the hereditary transmission o...

Paley's favourite word is "Contrivance"; and for him contrivance is most certain where production is most obscure. He points out the physiological advantage of the _valvulae con...

Darwin himself relates how illumination suddenly came to him. He had been reading, for his own pleasure, Malthus' book on Population, and, as he had long known from numerous obs...

(I) As everyone knows, the general idea of the Doctrine of Descent is that the plants and animals of the present day are the lineal descendants of ancestors on the whole somewha...

We come now to the _excitants_; that is, to the group of sexual characters whose origin through processes of selection has been most frequently called in question. We may cite t...

[Footnote 242: We can ignore here the metaphysical question of freewill and determinism. For the character of the individual's brain depends in any case on ante-natal accidents...

Spencer founded his "laws of evolution" on an inductive basis, but he was convinced that they could be deduced from the law of the conservation of energy. Such a deduction is, p...

Darwin sought to show, and succeeded in showing, that for the intellectual and moral life there are instinctive foundations which a biological treatment alone can disclose. It i...

10. The tendency of Comte and Buckle to assimilate history to the sciences of nature by reducing it to general "laws," derived stimulus and plausibility from the vista offered b...

It was clear from the first that it was essential, in the monistic conception of evolution, to distinguish between the laws of conservative and progressive heredity. Conservativ...

Organic selection has been termed a compromise between the more strictly Darwinian and the Lamarckian principles of interpretation. But it is not in any sense a compromise. The...

But this was not the case, as we can see from his admirable confession of faith, the publication of which we owe to his son Francis.[84] Whoever wishes really to understand the...

Lamarck[21] (1744-1829) seems to have thought out his theory of evolution without any knowledge of Erasmus Darwin's which it closely resembled. The central idea of his theory wa...

Now, if a determinant, for instance of a sensory cell, receives for a considerable time more abundant nutriment than before, it will grow more rapidly--become bigger, and divide...

But here we have reached a point of view from which the criticism, which in recent years has often been directed against Darwin--that small variations are of no importance in th...

The class of investigating minds is a small one, possibly even smaller than that of reflecting minds. Very few persons at any period are able to find out anything whatever. Ther...

The fundamental importance of this comparative morphology of the Mammals, as a sound basis of scientific anthropology, was recognised just before the beginning of the nineteenth...

In face of facts like these there can be no question of chance and no one has succeeded so far in finding any other explanation to replace that by selection. For the rest, the a...

Everything depends upon adaptation! We have spoken much of adaptation in colouring, in connection with the examples brought into prominence by Darwin, because these are conspicu...

In Italy independent work in the domain of the descent of man is being produced, especially by Morselli; with him are associated, in the investigation of related problems, Sergi...

Into the details of Mr. Wallace's criticisms it is impossible to enter here. We cannot discuss either the mode of origin of the variations in structure which have rendered secon...

But we can go further still. Whence comes the idea that all measures inspired by the sentiment of solidarity are contrary to Nature's trend? Observe her carefully, and she will...

Wallace, A. R., on Colour, 63, 71 --and Darwin, Foot Note 7, 23, 183 --on the Descent of Man, 116 --on Malthus, 17 --on Natural Selection, 2, 16, 163, 232