Again, in a passage dealing with the various ways of using life, so as to fill it full of beautiful energy, he says that “the wisest” spend it “in art and song.” In the later version he qualifies the words “the wisest” by the addition of the phrase “at least among ‘the children of this world.’” The alterations do not appear at first sight to have any very great significance; but Pater says that they brought out his original meaning more clearly; and the very minuteness of the changes serves at least to show his sense of the momentousness of phrases. He traces, in a passage of rich and subtle complexity, the bewildering effect upon the mind of the flood of external impressions; and compares it with the thought that gradually emerges, as the spirit deals with these impressions, of the loneliness, the solitude of personality; and with the mystery of the movement of time, the flight of the actual moment which is gone even while we try to apprehend it. He compares the perception to “a tremulous wisp constantly re-forming itself on the stream” of sense; and goes on to indicate that the aim of the perceptive mind should be to make the most of these fleeting moments, to “be present always at the focus where the greatest number of vital forces unite in their purest energy.” “To burn always with this hard, gemlike flame, to maintain this ecstasy, is success in life.” “Not to discriminate every moment some passionate attitude in those about us, is, on this short day of frost and sun, to sleep before evening.” He goes on to say that to get as many pulsations into the brief interval of life, is the one chance which is open to a man; and art, he says, gives most of these, “for art comes to you professing frankly to give nothing but the highest quality to your moments as they pass, and simply for those moments’ sake.” The “Conclusion,” then, is a presentment of the purest and highest Epicureanism, the Epicureanism that is a kind of creed, and realises the duty and necessity of activity and energy, but in a world of thought rather than of action. The peril of such a creed, of which Pater became aware, is that it is in the first place purely self-regarding, and in the second place that, stated in the form of abstract principles, it affords no bulwark against the temptation to sink from a pure and passionate beauty of perception into a grosser indulgence in sensuous delights. The difficulty in the artistic, as in the ethical scale, is to discern at what point the spirit begins to yield to the lower impulse; when it deserts the asceticism, the purity, the stainlessness of nature which alone can communicate that lucidity of vision, that seriousness of purpose, that ordered simplicity of life that is to be the characteristic of the nobler Epicureanism.