We will never find the sense of something (of a human, a biological or even a physical phenomenon) if we do not know the force which appropriates the thing, which exploits it, which takes possession of it or is expressed in it. A phenomenon is not an appearance or even an apparition but a sign, a symptom which finds its meaning in an existing force. The whole of philosophy is a symptomatology, and a semeiology. The sciences are a symptomatological and semeiological system. Nietzsche substitutes the correlation of sense and phenomenon for the metaphysical duality of appearance and essence and for the scientific relation of cause and effect. All force is appropriation, domination, exploitation of a quantity of reality. Even perception, in its diverse aspects, is the expression of forces which appropriate nature. That is to say that nature itself has a history. The history of a thing, in general, is the succession of forces which take possession of it and the co-existence of the forces which struggle for possession. The same object, the same phenomenon, changes sense depending on the force which appropriates it. History is the variation of senses, that is to say "the succession of more or less profound, more or less mutually independent processes of subduing" (GM II 12 p. 78). Sense is therefore a complex notion; there is always a plurality of senses, a constellation, a complex of successions but also of coexistences which make interpretation an art. "All subjugation, all domination amounts to a new interpretation."
Nietzsche's philosophy cannot be understood without taking his essential pluralism into account. And, in fact, pluralism (otherwise known as empiricism) is almost indistinguishable from philosophy itself. Pluralism is the properly philosophical way of thinking, the one invented by philosophy; the only guarantor of freedom in the concrete spirit, the only principle of a violent atheism. The Gods are dead but they have died from laughing, on hearing one God claim to be the only one, "Is not precisely this godliness, that there are gods but no God?" (Z III "Of the Apostates", p. 201). And the d**h of this God, who claimed to be the only one, is itself plural: the d**h of God is an event with a multiple sense. This is why Nietzsche does not believe in resounding "great events", but in the silent plurality of senses of each event (Z II "Of Great Events"). There is no event, no phenomenon, word or thought which does not have a multiple sense. A thing is sometimes this, sometimes that, sometimes something more complicated — depending on the forces (the gods) which take possession of it. Hegel wanted to ridicule pluralism, identifying it with a naive consciousness which would be happy to say "this, that, here, now" — like a child stuttering out its most humble needs. The pluralist idea that a thing has many senses, the idea that there are many things and one thing can be seen as "this and then that" is philosophy's greatest achievement, the conquest of the true concept, its maturity and not its renunciation or infancy. For the evaluation of this and that, the delicate weighing of each thing and its sense, the estimation of the forces which define the aspects of a thing and its relations with others at every instant — all this (or all that) depends on philosophy's highest art — that of interpretation. To interpret and even to evaluate is always to weigh. The notion of essence does not disappear here but takes on a new significance, for not every sense has the same value. A thing has as many senses as there are forces capable of taking possession of it. But the thing itself is not neutral and will have more or less affinity with the force in current possession. There are forces which can only get a grip on something by giving it a restrictive sense and a negative value. Essence, on the other hand, will be defined as that one, among all the senses of a thing, which gives it the force with which it has the most affinity. Thus, in a favourite example of Nietzsche's, religion does not have a unique sense, it serves many forces. But which force has the maximum affinity with religion? Which is the one where we can no longer know who dominates, it dominating religion or religion dominating it? For all things all this is a question of weighing, the delicate but rigorous art of philosophy, of pluralist interpretation.
Interpretation reveals its complexity when we realise that a new force can only appear and appropriate an object by first of all putting on the mask of the forces which are already in possession of the object. The mask or the trick are laws of nature and therefore something more than mere mask or trick. To begin with life must imitate matter merely in order to survive. A force would not survive if it did not first of all borrow the feature of the forces with which it struggles (GM III 8, 9, 10). Thus the philosopher can only be born and grow with any chance of survival by having the contemplative air of the priest, of the ascetic and religious man who dominated the world before he appeared. The fact that we are burdened by such a necessity not only shows what a ridiculous image philosophy has (the image of the philosopher-sage, friend of wisdom and ascesis) but also that philosophy itself does not throw off its ascetic mask as it grows up: in a way it must believe in this mask, it can only conquer its mask by giving it a new sense which finally expresses its true anti-religious force (GM III 10). We see that the art of interpreting must also be an art of piercing masks, of discovering the one that masks himself, why he does it and the point of keeping up the mask while it is being reshaped. That is to say that genealogy does not appear on the first night and that we risk serious misunderstanding if we look for the child's father at the birth. The difference in the origin does not appear at the origin — except perhaps to a particularly practised eye, the eye which sees from afar, the eye of the far-sighted, the eye of the genealogist. Only when philosophy has grown up can we grap its essence or its genealogy and distinguish it from everything that it originally had too great a stake in being mistaken for. It is the same for every thing. "In all things only the higher degrees matter!" (PTG). The problem is one of origin but origin conceived as genealogy can only be determined in relation to higher degrees.
Nietzsche says that there is no need to wonder what the Greeks owe to the East (PTG). Philosophy is Greek insofar as it is in Greece that it attains its higher form for the first time, that it first shows its true force and its goals — these are not the same as those of the Eastern priest even when they are made use of. Philosophos does not mean "wise man" but "friend of wisdom". But "friend" must be interpreted in a strange way: the friend, says Zarathustra, is always a third person in between "I" and "me" who pushes me to overcome myself and to be overcome in order to live (Z I "Of the Friend" p. 82). The friend of wisdom is the one who appeals to wisdom, but in the way that one appeals to a mask without which one would not survive, the one who makes use of wisdom for new, bizarre and dangerous ends — ends which are, in fact, hardly wise at all. He wants wisdom to overcome itself and to be overcome. The people are certainly not always wrong: they have a foreboding of the essence of the philosopher, his anti-wisdom, his immoralism, his conception of friendship. Humility, poverty, chastity — we can guess the sense that these wise and ascetic values take on when they are revived by philosophy, by a new force (GM III 8).