At the end of Book Four of The World as Will and as Representation, Schopenhauer has the following to say:
Thus, in this way, by contemplation of life and conduct of saints, whom it is certainly rarely granted us to meet with in our own experience, but who are brought before our eyes by their written history, and, with the stamp of inner truth, by art, we must banish the dark impression of that nothingness which we discern behind all virtue and holiness as their final goal, and which we fear as children fear the dark; we must not even evade it like the Indians, through myths and meaningless words, such as reabsorption in Brahma or the Nirvana of the Buddhists. Rather do we freely acknowledge that what remains after the entire abolition of will is for all those who are still full of will certainly nothing; but, conversely, to those in whom the will has turned and his denied itself, this our world, which is so real, with all its suns and milky ways—is nothing.
This passage is important in that it points toward the role of “nothingness” in his philosophy. The basic idea is clear enough. The denial of the Will, which is the route towward total abandonment of the perceptible world or the world of representations, which leads eventually to total extinction of the Will itself and all sufferings, results ultimately in “nothing”. The world of the saints who have successfully extinguished all their desires is nothing for us. Analogously, our own world, which is full of individual objects and all the desires, is “nothing” for the saints and the holy men and women too.
This may sound quite like Buddhism, but in fact it is not. Anyway it depends very much on how the word “nothing” is interpreted. Does Schopenhauer mean that, beyond the perceptual capacity of an ordinary person who is still under the influence of the Will to perceive, any aspect of reality is ultimately nothing at all? Does ‘nothing’ mean ‘no thing’? But in a real sense the world beyond the Principle of Individuation consists of no thing at all, because for anything to be a thing it has to be individuated, and that requires the work of the Will itself through the Principle of Indivuduation. Since Schopenhauer is saying that the Will itself constitutes the material world, then what results from the denial of the Will should be absolutely nothing, zip, nada.
But if that is an accurate interpretation of Schopenhauer, then not only does this contradict with what the Buddhists, especially Nagarjuna, has to say regarding their own ideas on Emptiness, it also creates a lot of difficulty for Schopenhauer’s overall argument itself. If what results from deying the Will is just nothing, then why spent many hundred pages talking about it as if it is worth taking the effort to do so? Why praise all these saints and holy people since what they finally achieve for their strenuous efforts is, well, nothing? If nothing results from denying the will, then why put this topic as a separate section as if it is something important?
But the problem is that Schopenhauer does not talk much at all about this nothing. Perhaps there’s nothing to say. But at the very end of Book Four he has a quote to a German translation of the Prajñā-pāramitā, which, as Buddhists know, talks about there being “no things” too. Is Schopenhauer confused between the “nothing” mentioned in the Prajñā-pāramitā with the usual conception of nothing in Western philosophy?
In any case, it does not make much sense for Schopenhauer to say that the “nothing” which results from denying the Will is just nothing at all. This also pertains to the bedrock of his system — the argument about the distinction between the representations and the Will itself. I believe that Schopenhauer believes that the two are ultimately one and the same, since he says repeatedly that the representations themselves are nothing but the Will. So if they are separate then the representaions would not be the same as the Will.
So it seems that the “nothing” is not “nothing” at all; there has to be something in the nothing. And this is in accord with what the Prajñā-pāramitā is saying. But what Schopenhauer does not spell out is how something could be “not nothing” (because if it were nothing then there would not be any point to the denial of the Will as I have said) and at the same time actually “nothing” (because it has to go beyond the Principle of Indivduation). But this is exactly what Nāgārjuna is doing.