The world of appearance does not strike us as a "valuable" world; appearance is on a lower plane than the highest value. Only a "real" world can be absolutely "valuable"....
Prejudice of prejudices! It is perfectly possible in itself that the real nature of things would be so unfriendly, so opposed to the first conditions of life, that appearance is necessary in order to make life possible.... This is certainly the case in a large number of situations—for instance, marriage.
Our empirical world would thus be conditioned, even in its limits to knowledge, by the instinct of self-preservation, we regard that as good, valuable, and true, which favours the preservation of the species....
(a) We have no categories which allow us to distinguish between a real and an apparent world. (At the most, there could exist a world of appearance, but not our world of appearance.)
(b) Taking the real world for granted, it might still be the less valuable to us; for the quantum of illusion might be of the highest order, owing to its value to us as a preservative measure. (Unless appearance in itself were sufficient to condemn anything?)
(c) That there exists a correlation between the degrees of value and the degrees of reality (so that the highest values also possessed the greatest degree of reality), is a metaphysical postulate which starts out with the hypothesis that we know the order of rank among values; and that this order is a moral one. It is only on this hypothesis that truth is necessary as a definition of all that is of a superior value.
B.
It is of cardinal importance that the real world should be suppressed. It is the most formidable inspirer of doubts, and depredator of values, concerning the world which we are: it was our most dangerous attempt heretofore on the life of Life.
War against all the hypotheses upon which a real world has been imagined. The notion that moral values are the highest values, belongs to this hypothesis.
The superiority of the moral valuation would be refuted, if it could be shown to be the result of an immoral valuation—a specific case of real immorality: it would thus reduce itself to an appearance, and as an appearance it would cease from having any right to condemn appearance.