Readers should think of the relationship between the rational man and the intuitive man is much like, although not the same as, the relationship between the Apollonian and the Dionysian in the Birth of Tragedy. It is similarly a kind of marriage that involves both conflict and reconciliation. N. speaks of their conflict, for example, when he speaks of ages in which the rational man fears intuition and the intuitive man scorns abstraction. But there are also implicit reconciliations in the need that the intuitive man has for the very structures set up by the rational man. You cannot creatively violate structures if they are not already constructed. The Dionysian represents the inexpressible truth of the real world that underlies all of our experience, and it is expressible only by way of myth of the tragic play. So too, the intuitive man cannot express what he perceives except in metaphor and image. Note that even when the intuitive man is dominant, presumably in the classical period of ancient Greece, and has assured "art's mastery over life," it is through a kind of illusion (different from that of the rational man), one based on disregarding the very needs to which the rational man is so attentive, for example "foresight, prudence, and regularity." The point is that there is disguise on both sides, both for the rational man and for the intuitive man, the later disguising needs under or behind "illusion and beauty."
In a culture like that of classical Greece, houses, personal style, clothes, and pottery are all invented and beautified with less regard for need than for expression of happiness. Nietzsche, interestingly, identifies this with the Apollonian world of "Olympian cloudlessness." So, we are not to strictly identify the Socratic or Alexandrian rational man with the Apollonian. Actually the reverse is true since, here, the Apollonian/Olympian is identified with the man of intuition.
Now, to be sure, the intuitive man is a different type than the rational man, and Nietzsche would certainly rather be an intuitive man than a rational man. For example, the rational man only seeks to avoid pain whereas the intuitive man reaps "continually inflowing illumination, cheer, and redemption" while, at the same, time avoiding misfortune. And when he does suffer he does so more intensely and frequently. Nietzsche likens him to Thales, the ur-philosopher, who falls into a ditch when looking at the stars. The intuitive man is just not practical and does not learn from experience. Nietzsche ends this unfinished essay with a contrast between the intuitive man and the stoical man (presumably a sub-type of the rational man). The later creates his own deception insofar as in misfortune he wears a mask "with dignified symmetrical features." But if he were to go on he would surely say that the rational man is needed as much as the intuitive man for the further development of culture. Also, since the intuitive man represents what he later calls the Apollonian, and the rational man represents what he later calls the Alexandrian, we should anticipate his also introducing the Dionysian man, which, of course, he does in The Birth of Tragedy.
The essay, one might say, is more about intellect than it is about truth. For example, at the beginning we learn that man is just another animal and that his intellect is a tool much like claws for a bear. To put human intellect in its place is not to deny truth or to deny that truth exists, however. For Nietzsche, the intellect deceives us in the first place by the haughtiness and self-satisfaction we get from the knowledge we have (or perhaps the "knowledge" we have). This seems like such a great thing that man is deceived about the value of his own existence. His evaluation of knowledge is itself self-flattering. We think ourselves greater than other species because we have this marvelous thing called knowledge. What the intellect mainly does however (and intellect is not really to be distinguished here from "knowledge"), in its effort to preserve the individual, is to simulate, deceive, flatter, lie, cheat.... etc. So how do we make sense of the notion of the "pure urge to truth"? That is Nietzsche's main question.
But this question is not, in itself, a denial of truth or a claim that truth does not exist. The trouble is with language, the main instrument of our intellect, and more particularly with language in its static, literal or, to be more dramatic, dead state. Nietzsche does not deny that there is a world that we experience or even gain knowledge of. The problem is with our instrument, or rather with how we usually see it. We usually see it as paradigmatically literal. And the problem isn't that literal language is without value. It has immense value. The value however is not contained in the notion that it is the main instrument of the search for truth. Actually, it is metaphorical language that is the main instrument for that search. Bear in mind that, as creativity researchers have long known, only when creative thinkers break conventional boundaries and use words in non-literal ways do we have advances in knowledge.
In reading the essay one must always keep in mind the radical distinction between real truth, or perhaps better, just Reality, and what we will call "truth." I will refer to the former as Truth and the latter by putting "truth" with scarequotes. "Truth" consists of most of the things that are actually held to be true and which constitute, however, a kind of useful illusion. For example, we might think that the explanation for why someone does something honest is because he has the internal quality of honesty, but in fact, "honesty" is just a useful fiction that "explains" without really explaining. (This kind of fiction can get in the way of being a good teacher, for example when one thinks that a student plagiarizes because he is a dishonest person. Useful falsehoods are not always useful.) Truth is available to the intuitive man (or, rather, the intuitive aspects of ourselves and our cultures), or better, to the tragic man who combines both the Apollonian and the Dionysian. By contrast, "truth" is the only thing available to the rational man. Nietzsche does not deny truth. But neither does he deny "truth," since "truth" does have value. He simply denies that "truth" is equal to truth, i.e. the true truth.
A nice way to understand Truth for Nietzsche is that it is like Heidegger's notion of truth as unconcealment.
Clark worries about the common belief that "Nietzsche proves the non-existence of truth, at least of any truths accessible to humans." And yet there is nothing to worry about here since he does not deny such existence and even allows that truth is accessible to the intuitive man (and implicitly to man insofar as it is only by working together that the rational and intuitive man can arrive at it). Or, perhaps better, it is accessible to the Dionysian man, or even better, the tragic man.
But part of Clark's concern is whether he denies that "any of our beliefs correspond to reality." What would Nietzsche say in response to that? If all of our beliefs are in the form of statements made using words that are essentially dead metaphors then I doubt that he does believe that any of those correspond to reality. Words that are living may not correspond to reality if one means by that that there is a one to one matching of sentence to fact as in "snow is white" is true if and only if snow is white. But they could well be said to correspond to reality when they express truth via live metaphor, if by "correspond" is meant that there is a harmonious convergence between the language and that which it expresses.
Clarke finds an "explicit denial of truth" in the famous paragraph that begins "What, then, is truth?" Nietzsche follows the question with an answer: it is a "mobile army of metaphors, metonyms, and anthropomorphisms" so that it is really "a sum of human relations" which have been enhanced and embellished, at first, but then, and this is important, have been used for so long that they "seem firm, canonical, and obligatory." It is from this point that he comes to the conclusion that "truths are illusions about which one has forgotten that this is what they are." Clearly N. is talking here not about truths but about "truths." The rational man lives with "truths" and with the illusion that they are not dead metaphors. Ironically the original metaphors from which they came are more true than they are. Nietzsche speaks of "truths" as "metaphors which are worn out and without sensuous power." This is intended to contrast with the metaphors that have not lost sensuous power, i.e. the metaphors that give us access to true truth. Following this, the "urge to truth" is really the urge to "truth," that is, metaphors that are "customary" and hence dead
Relying on "truths" based on dead metaphors is nothing more than lying "according to fixed conventions." It is an unconscious lie. Clark thinks this is a denial of truth, but it is only a claim about the uses of "truth." And it isn't even a denial of "truth" since, again, it is not denied that "truths" are immensely useful. (One could say that Nietzsche holds a pragmatist theory of "truth" but not a pragmatist theory of Truth. Again, his theory of Truth is more like Heidegger's.) Clark thinks these are not really lies since to lie you have to consciously tell a falsehood, but of course one can lie by way of being in denial about something one knows deep down.
Clark believes that N. thinks that all assertions we call truths are actually false: but this is not true. It is that all assertions that the rational man calls truths are false. Only some of the assertions the intuitive man calls truths are false. So N. is not guilty of claiming that any true assertion is also false and is not guilty of absurdity. The point is so simple, one wonders how carefully Clarke read the text. Clark's mistake in interpreting and evaluating N.s theory is just another example of what happens when philosophy fails to recognize the centrality of aesthetics to its enterprise. In fact, her mistake is just exemplification of over-reliance of the rational man, and no real recognition of the intuitive man, or the way in which they two inter-relate, all of which is pretty typical of contemporary professional philosophy.
Thinking about a friend's comments on this piece I want to make clear that I am not coming here from a position of dualism. My thought is that in order to even talk about deception you have to believe there is some truth that is being hidden by the deception. So I do not see how N. can reject truth. He must hold that although almost all things previously thought true are deceptions what HE is giving us is at least closer to truth. Similarly, to know, as N. claims, that men are deceived about the value of existence one has to have knowledge of the true value of existence. When N. asks “If truth alone had been the deciding factor in the genesis of language, and if the standpoint of certainty had been decisive for designations, then how could we still dare to say "the stone is hard," as if "hard" were something otherwise familiar to us, and not merely a totally subjective stimulation!” he is saying that “the stone is hard” is both false and totally subjective. Any claim that something is false, and N. makes such a claim, implies that one believes something else is true. If “truth” is worn metaphors without sensuous meaning then Truth is live metaphors. Illusion is created by language, yes, but when that language is living, and is no longer merely a matter of propositions claiming to correspondence, then truth is possible, not as revelation but as poetic truth. Not only does N.s view of Truth overcome dualism it also overcomes subjective/objective duality. Hence it makes sense to speak of Truth as something that happens, in Heidegger's sense.