“In this precise sense, Kant was "the inventor of the philosophical history of philosophy": there are necessary stages in the development of philosophy, that is, one cannot directly get at the truth, one cannot begin wit it, philosophy necessarily began with metaphysical illusions. The path from illusion to its critical denunciation is the very core of philosophy, which means that successful ("true") philosophy is no longer defined by its truthful explanation of the totality of being, but by successfully accounting for the illusions, that is, by explaining not only why illusions are illusions, but also why they are structurally necessary, unavoidable, and not just accidents.”

trans. Michael Chase, p. 271
La Philosophie comme manière de vivre (2001)

Source: The Count of Monte Cristo

Source: The Thirst for Annihilation: Georges Bataille and Virulent Nihilism (1992), Chapter 1: "The death of sound philosophy", p. 1

Source: Lectures on the Will to Know (1970), pp. 4-5

Ueberhaupt aber bin ich allmälig der Meinung geworden, daß der erwähnte Nutzen der Kathederphilosophie von dem Nachtheil überwogen werde, den die Philosophie als Profession der Philosophie als freier Wahrheitsforschung, oder die Philosophie im Auftrage der Regierung der Philosophie im Auftrage der Natur und der Menschheit bringt.
Sämtliche Werke, Bd. 5, p. 151, E. Payne, trans. (1974) Vol. 1, p. 139
Parerga and Paralipomena (1851), On Philosophy in the Universities

The Story of Philosophy (1926)

Persecution and the Art of Writing (1952), Introduction

Part I : Ambiguity and Freedom
The Ethics of Ambiguity (1947)
Context: From the very beginning, existentialism defined itself as a philosophy of ambiguity. It was by affirming the irreducible character of ambiguity that Kierkegaard opposed himself to Hegel, and it is by ambiguity that, in our own generation, Sartre, in Being and Nothingness, fundamentally defined man, that being whose being is not to be, that subjectivity which realizes itself only as a presence in the world, that engaged freedom, that surging of the for-oneself which is immediately given for others. But it is also claimed that existentialism is a philosophy of the absurd and of despair. It encloses man in a sterile anguish, in an empty subjectivity. It is incapable of furnishing him with any principle for making choices. Let him do as he pleases. In any case, the game is lost. Does not Sartre declare, in effect, that man is a “useless passion,” that he tries in vain to realize the synthesis of the for-oneself and the in-oneself, to make himself God? It is true. But it is also true that the most optimistic ethics have all begun by emphasizing the element of failure involved in the condition of man; without failure, no ethics; for a being who, from the very start, would be an exact co-incidence with himself, in a perfect plenitude, the notion of having-to-be would have no meaning. One does not offer an ethics to a God. It is impossible to propose any to man if one defines him as nature, as something given. The so-called psychological or empirical ethics manage to establish themselves only by introducing surreptitiously some flaw within the manthing which they have first defined.

Source: Leisure, the Basis of Culture (1948), The Philosophical Act, pp. 127–128
The "interpretation of Plato" referred to is that of Gerhard Krüger, Einsicht und Leidenschaft (Frankfurt, 1939), p. 301.