This anomaly supports the weak side of Mr. Carus's system. The learned Saxon amuses himself by supposing that, just as we see our planet pass through the four stages of day, night, morning twilight, and evening twilight, so there _must_ be four subdivisions of the human species, corresponding to these variations of light. He perceives in this a symbol,[130] which is always a dangerous temptation to a mind of refined susceptibilities. The white races are to him the nations of day; the black, those of night; the yellow, those of morning; the red, those of evening. It will be perceived how many ingenious analogies may be brought forward in support of this fanciful invention. Thus, the European nations, by the brilliancy of their scientific discoveries and their superior civilization, are in an enlightened state, while the blacks are plunged in the gloomy darkness of ignorance. The Eastern nations live in a sort of twilight, which affords them an incomplete, though powerful, social existence. And as for the Indians of the Western World, who are rapidly disappearing, what more beautiful image of their destiny can be found than the setting sun? Unfortunately, parables are no arguments, and Mr. Carus has somewhat injured his beautiful theory by unduly abandoning himself to this poetical current. Moreover, what I have said with regard to all other ethnological theories--those of Camper, Blumenbach, and Owen--holds good of this: Mr. Carus does not succeed in systematizing regularly the whole of the physiological diversities observable in races.[131] The advocates for unity of species have not failed to take advantage of this inability on the part of their opponents to find a system which will include the many varieties of the human family; and they pretend that, as the observations upon the conformation of the skull cannot be reduced to a system which demonstrates the original separation of types, the different varieties must be regarded as simple divergencies occasioned by adventitious and secondary causes, and which do not prove a difference of origin.