The expression of conditions of existence, so often insisted on by the illustrious Cuvier, is fully embraced by the principle of natural selection.

杰出的居维叶 (Cuvier) 经常坚持的生存条件的表达完全被自然选择的原则所接受。

Then from a lack of perception, since you must operate within the world as you perceive it, then the opposites will appear to be conditions of existence.

然后由于缺乏知觉，因为你必须在你所感知的世界中运作，那么对立面将看起来是存在的条件。