Why did Nietzsche dislike Kant and his epistemology so much?

Question

So many books where Nietzsche criticizes Kant and express his contempt about the "categorical imperative" for example in "Beyond Good and Evil":

The spectacle of the Tartuffery of old Kant, equally stiff and decent, with which he entices us into the dialectic by-ways that lead (more correctly mislead) to his "categorical imperative"--makes us fastidious ones smile, we who find no small amusement in spying out the subtle tricks of old moralists and ethical preachers.

Later he says:

People had been dreaming, and first and foremost--old Kant. "By means of a means (faculty)"--he had said, or at least meant to say. But, is that--an answer? An explanation? Or is it not rather merely a repetition of the question? How does opium induce sleep? "By means of a means (faculty)," namely the virtus dormitiva, replies the doctor in Moliere,

Quia est in eo virtus dormitiva, Cujus est natura sensus assoupire.

One of the roughest I think, but there are a lot more. So, can we conclude that Nietzsche detested Kantian philosophy? And why?

Answer 1

METAPHYSICS

• Kantian philosophy could represent a huge hope for nietzschean philosophy and its fight against nihilism : Kant shows that metaphysical Ideas are meaningless from a theoretical standpoint, that they are mere illusions!

• But immediately after having destroyed metaphysics from a theoretical standpoint , Kant " rebuilds" it so to say from a practical standpoint : we need the hypotheses of God and of Soul in order to give a meaning to ethics ( though we do not need these " postulates" to act morally).

• So, Kant has refuted the Theoretical God ( ens perfectissimum, necessary being, first cause, etc) only to replace it by the Moral God. from Nietzsche's point of view, this is treason. Worst, it is the culmination of nihilism : nihilist metaphysics in a new guise finally shows itself as it is , a product of slave-ethics , that is of resentment.

• When Nietzsche said that " God is dead" , his talk is precisely about Kant's Moral God.

• Even some christians, more precisely some catholics, side with Netzsche in saying that this Moral God is refuted and was , in the end , an idol.

See : Jean Luc Marion

• So much for the metaphysical aspect of the question.

EPISTEMOLOGY

• Now, regarding the epistemological aspect , Nietzsche once again accuses Kant of having gone only half-way in his anti-dogmatic revolution, and of having therefore betrayed this " coperniciaan revolution".

• Kant in a sense is right in stating that there are " synthetic a priori" judgments. What is right in Kant's conception is that knowing requires not an adaptation of human intellect to things in themselves ( "the old adaequatio intellectus et rei") , but , first of all, an adaptation of reality to our own forms of thought. " The conditions that make experience possible are also the conditions of the objects of experience" : supreme ground of synthetic judgments.

• But, although Kant reversed the sense of the mind-reality correspondence, he never questionned the very idea of truth as correspondence. This is why , from his point of view, the question of " synthetic a priori" judgments took the form : how are these judgments possible? That is : how is it possible that our a priori judgments correspond to reality? how is it possible that they be true?

• Because Kant was trying to explain something imaginary ( the a priori correspondance of reality to our thought) , the explanation had to be imaginary itself. We have a priori synthetic knowledge because we have an " a priori knowledge faculty" , that is pure reason, more precisely, pure understanding that has the power to impose its laws to nature ( empirical world). The explanation is obviously tautologous and sterile.

• In order to bring his epistemological revolution to its completion, Kant should have recognized that " a priori synthetic" judgments are not true, not even true in a transcendental way ( as conditions of experience). For, not only " reality in itself" cannot correspond to these judgments ( kant already knew this) but phenomenal reality cannot either : the phenomenal world of experence is totally foreign to our concepts ( substance, cause, etc.) and to our logic ( even our " transcendental logic").

• So had Kant been honest, he would have accomplished a " pragmatic" turn by giving up the idea of truth as correspondence and by adopting the notion of truth as " what works", or " what is useful for life". Since there is no possible correspondence, this truth is a form of falsehood , but it is a useful one : we need to create a "reality" stable enough, ordered enough, logical enough, in order to be able to live in this world.

• So the right question is not " what makes a priori synthetic judgments possible", but what makes them necessary, from a pragmatic ( vital ) standpoint. (Note that there is a shift from "true" to "good" ( for life) : knowledge is a matter of value.)

• Note : the key point is to understand that, according to Nietzsche, there is no opposition between truth and falsehodd, because truth is nothing else than a kind of falehood ( any perspective on reality being necessarily false , inadequaate, non-corresponding). What kind of falsehood? The one that is useful for life.

“For us, the falsity of a judgment is still no objection to that judgment — that’s where our new way of speaking sounds perhaps most strange. The question is the extent to which it makes demands on life, sustains life, maintains the species, perhaps even creates species. And as a matter of principle we are ready to assert that the falsest judgments (to which a priori synthetic judgments belong) are the most indispensable to us, that without our allowing logical fictions to count, without a way of measuring reality against the purely invented world of the unconditional and self-identical, without a constant falsification of the world through numbers, human beings could not live — that if we managed to give up false judgments, it would amount to a renunciation of life, a denial of life.

To concede the fictional nature of the conditions of life means, of course, taking a dangerous stand against the customary feelings about value. A philosophy which dares to do that is for this reason alone already standing beyond good and evil.”

Beyond Good and Evil.