According to general opinion, however, there is one feature of culture which characterizes it better than any other, and that is the value it sets upon the higher mental activities—intellectual, scientific, and aesthetic achievement—the leading part it concedes to ideas in human life. First and foremost among these ideas come the religious systems with their complicated evolution, on which I have elsewhere endeavoured to throw a light; next to them come philosophical speculations; and last, the ideals man has formed, his conceptions of the perfection possible in an individual, in a people, in humanity as a whole, and the demands he makes on the basis of these conceptions. These creations of his mind are not independent of each other; on the contrary, they are closely interwoven, and this complicates the attempt to describe them, as well as that to trace their psychological derivation. If we assume as a general hypothesis that the force behind all human activities is a striving towards the two convergent aims of profit and pleasure, we must then acknowledge this as valid also for these other manifestations of culture, although it can be plainly recognized as true only in respect of science and art. It cannot be doubted, however, that the remainder, too, correspond to some powerful need in human beings—perhaps to one which develops fully only in a minority of people. Nor may we allow ourselves to be misled by our own judgements concerning the value of any of these religious or philosophical systems or of these ideals; whether we look upon them as the highest achievement of the human mind, or whether we deplore them as fallacies, one must acknowledge that where they exist, and especially where they are in the ascendant, they testify to a high level of civilization.