nd why do species die? Why does nature put so high a premium on generation? And why does generation have the twofold character of perpetuation and variation". It seems that apart from the occasional reference to "adaptation", Darwin, at that time, almost deliberately tried to avoid the contemporary theories of the mechanics of evolution. Notwithstanding, Darwin, sooner or later, had to confront the question of "how" evolution occurred. Amusingly, he happened to stumble upon the answer quite accidentally. In his spare time Darwin enjoyed reading various books rather aimlessly, for amusement. One of these books, which he read in October 1838, happened to be Malthus' Essay on the Principle of Population. As Darwin himself later related, "Malthus' description of the struggle for existence in human society immediately suggested to him that under the competitive conditions of animal and plant life, favorable variations would tend to be preserved, and unfavorable ones destroyed, the result being the formation of new species". By this chance encounter than, Darwin's theory was provided with a rationale, and the "how" of evolution came to supplement the "why".It is important to note, that even though Malthus inspired the crux of Darwin’s theory, Darwin diverged from Malthus in a critical way. Darwin's debt to Malthus lies in the borrowing of the concept of the "struggle for existence". However, in general, what Malthus was concerned about was not how the struggle for existence affected the quality of the population (i.e., he did not suggest that in the struggle for existence the strong survive and the weak perish) but simply how it limited its numbers. Indeed, Malthus' essay was written as a rebuttal to Godwin and Condorcet, both of whom had argued that humans, under conditions of equality, were capable of infinite progress and perfection. In the essay Malthus advanced the "principle of population" to refute that idea. Thus, Malthus' prin...
