Part of Nietzsche’s problem with history, science, and the knowledge drive in general is that these activities typically presuppose that "knowing" is possible, and that truth is more valuable than untruth, or appearance. It is supposed that there is another world, one free from our perceptions, which can be known if we can find an objectifying lens through which the real nature of things, i.e. inherent properties, things-in-themselves, essences, can be understood. Nietzsche sees most endeavors concerned with discovering the truth as attempts to separate the knower from the known in such a way that they can separate their perceptions (the way the world seems) from the perceived object (an entity that has an existence free from what we bring to the word.) With this separation of the world into "the world of mere appearances" and the "real world," objects are seen as things-in-themselves, with inherent meanings that are non-revisable, objective, and universal ("The Philosopher" 133). And it is hoped that by finding this truth, this real world, we can free ourselves from the contradictory, deceptive, and transitory nature of the apparent world, for this world just causes us grave suffering (WP 585).
The problem with this, Nietzsche claims, is that there is no such thing as immediate and direct access to objects, and thereby no thing-in-itself, for man is standing in the way, he conceals things (DB 438). What this means is that the Truth, or essence, of a thing cannot be known, for this would require a self-contradictory mediated immediacy, to borrow a phrase from Kaufmann. As Nietzsche says in his notebooks, "we can say nothing about the thing in itself, for we have eliminated the standpoint of knowing, i.e. of measuring. A quality exist for us, i.e. it is measured by us" ("The Philosopher" 101). Or as he warns in GM 3:12, "let us guard against such contradictory concepts as ‘pure reason,’ ‘absolute spirituality;’ ‘knowing in itself,’ for these demand that ‘we should think of an eye that is completely unthinkable, an eye turned in no particular direction…these always demand of the eye an absurdity and a nonsense. There is only a perspective seeing, only a perspective ‘knowing’."
This does not mean, however, that an individual’s perception can facilitate an understanding of things-in-themselves either; it means that existence is nonsensical without interpretation (DB 125). All we can discover in trying to examine a thing-in-itself is "things upon it," namely our perceptions, which themselves depend on sensations and such. But, as Nietzsche claims, "The habits of our senses have woven us into lies and deceptions of sensations"(DB 117). In other words, even the senses we rely on to "see" things are inherently faulty: we think that through our senses we can observe things "how they are," but this is not possible: we have no access to "things-in-themselves." Our senses may take in the environment as it appears, our eyes may see a table, but it is nonsense without interpretation and language. For Nietzsche, each individual experiences things through his or her own senses and thereby his or her own perspective: each individual is a self-enclosed being with access only to those things he or she can catch in his or her own net. As he comments, "my eyes… can only see a certain distance, and it is within the space encompassed by this distance that I live and move…. our ears enclose us within a comparable circle, and so does our sense of touch. Now, it is by these horizons, within which each of us encloses his senses as if behind prison walls, that we measure the world" (DB: 117, my emphasis).
This disavowment with our senses, Nietzsche argues, has led many a philosopher and scientist to posit our reasoning faculties as the means by which to establish the criterion of truth. It was hoped that through scientific rationality the properties of things could be determined and that we could thereby establish the rules for determining the "real" and the "unreal," thereby achieving mind-independent representations of the world (see WP 584). It is then assumed that knowing is the ability to represent accurately what is outside the mind. Nietzsche asks, however, would not we already have to know what being is in order to determine if something is real or not? (see GS 354; WP 486). Without already knowing what an accurate representation might be, we are unable to say that it is an accurate representation, and this is not something we can know: we simple lack an organ for knowing, for "truth" (GS 354).
Nietzsche is willing to admit that we are acquainted with reality but the reality of our thoughts, language, and consciousness, the realm that supposedly makes up the kernel of mankind and makes man most human ("The Philosopher" 94; GS 11). And it is this realm, the realm of thoughts, which we take, in comparison with the realm of actions, willing, and experiences, to be the realm of our freedom (BD 125). To this Nietzsche must respond that we are again gravely mistaken: for thinking itself is language, and thereby our consciousness is nothing more than language. While in words we assume we are able to share our experiences with others to thereby break free of our prison caused by sensation, we are mistaken in thinking that words, a social convention, can really give individuals private expressions or allow for self-understanding. How this can be is simple: thought or "consciousness does not belong to an individual’s existence but rather to his social nature…and that fundamentally, all out actions are altogether incomparably personal, unique, and infinitely individual; but as soon as we translate them into consciousness they no longer seem to be" (GS 354).
