A great principle of charity in morals is not to blame the fishes for their bad taste in liking to live under water. Yet many philosophers seem to have sinned against this reasonable law, since they have blamed life and nature for liking to change, which is as much as to say for liking to live. Certainly life and nature, when they produce thought, turn from themselves towards the eternal, but it is by a glance, itself momentary, that they turn to it; for if they were themselves converted into something changeless, they could neither live, think, nor turn. In the realm of existence it is not sinful to be fugitive nor in bad taste to be new. Accordingly cloud castles have nothing to blush for; if they have a weak hold on existence, so has everything good. We are warned that the day of judgement will be full of surprises: perhaps one of them may be that in heaven things are even more unstable than on earth, and that the mansions reserved for us there are not only many but insecure. Cloud castles are hints to us that eternity has nothing to do with duration, nor beauty with substantial existence, and that even in heaven our bliss would have to be founded on a smiling renunciation. Did Mohammed, I wonder, misunderstand the archangel Gabriel in gathering that celestial beauties (unlike the lights and voices of Dante's paradise) could be embraced as well as admired? And in promising that our heavenly brides would daily recover their virginity, did he simply clothe in a congenial metaphor the fact that they would be different brides every day, and that if we wished to dwell in a true paradise, and not in a quarrelsome and sordid harem, we must never dream of seeing any of them a second time?