The point is not that this world is too sad to love or too glad not to love; the point is that when you do love a thing, its gladness is a reason for loving it, and its sadness a reason for loving it more.
The world is constantly changing. You're constantly learning and you have to be willing to get off your mark, and get off your spot and take that knowledge you have not to fix yourself into a place but to keep going.
Will without intellect is the most vulgar and common thing in the world, possessed by every blockhead, who, in the gratification of his passions, shows the stuff of which he is made.
Science, already oppressive with its shocking revelations, will perhaps be the ultimate exterminator of our human species - if separate species we be - for its reserve of unguessed horrors could never be borne by mortal brains if loossed upon the world.