The work for which Thomas Malthus is still most widely known is his Essay on the Principle of Population, which first appeared in 1798. This book introduced Malthus’s【C1】______ that population inescapably outgrows subsistence(生活资料), and that this difference【C2】______ population size and the ability to adequately meet the【C3】______ subsistence needs of all the members of that population “ naturally ” produces a fundamental struggle for【C4】______ , in which some flourish at the【C5】______ of others.

Charles Darwin’s most important contribution【C6】______ the field of biology, described in his work, On the Origin of Species, was to【C7】___Malthus’s observation that plants and animals multiply faster than nature can provide for them to his own【C8】___ of the process of “evolution”—the notion that different forms of life develop【C9】______ from a common ancestry(祖先). Combining these elements, Darwin【C10】___that the factors of “ the struggle for existence” and “the survival of the fittest” are the central mechanisms【C11】___ which evolution is based. In this sense, then, Darwin introduced the possibility【C12】______ conflict and struggle are biological phenomena, which are【C13】______central to human social existence.

A number of more contemporary social thinkers were【C14】______ by Darwin and continued this particular version of the conflict perspective, commonly referred to【C15】______ social Darwinism, into the twentieth century. Thus, for example, Herbert Spencer, a【C16】______ English social theorist, applied these ideas of the natural【C17】___of conflict and survival of the fittest to his notion of social evolution,【C18】___ William Graham Sumner, an American sociologist, saw the【C19】______ for survival among individual actors as operating to bring about fundamental【C20】______ in the quality of human social life overall.

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