“I learnt to see philosophical systems in the context of the social milieu which produced them. I therefore learnt to look for social contention in philosophical systems. It is of course possible to see the history of philosophy in diverse ways, each way of seeing it being in fact an illumination of the type of problem dealt with in this branch of human thought. It is possible, for instance, to look upon philosophy as a series of abstract systems. When philosophy is so seen, even moral philosophers, with regrettable coyness, say that their preoccupation has nothing to do with life. They say that their concern is not to name moral principles or to improve anybody's character, but narrowly to elucidate the meaning of terms used in ethical discourse, and to determine the status of moral principles and ru1es, as regards the obligation which they impose upon us. When philosophy is regarded in the light of a series of abstract systems, it can be said to concern itself with two fundamental questions: first, the question 'what there is'; second, the question how 'what there is' may be explained. The answer to the first question has a number of aspects. It lays down a minimum number of general under which every item in the world can and must be brought. It does this without naming the items themselves, without furnishing us with an inventory, a roll-call of the items, the objects in the world. It specifies, not particu1ar objects, but the basic types of object. The answer further implies a certain reductionism; for in naming only a few basic types as exhausting all objects in the world, it brings object directly under one of the basic types.”

Anarchism or Socialism (1906)

Rebecca Goldstein, Betraying Spinoza: The Renegade Jew Who Gave Us Modernity (New York: Schocken, 2006)
G - L

From Critical and Speculative Philosophy (1924)

Preface
Philosophy and the Mirror of Nature (1979)

[O] : Introduction, 0.6
Semiotics and the Philosophy of Language (1984)
Context: When semiotics posits such concepts as 'sign', it does not act like a science; it acts like philosophy when it posits such abstractions as subject, good and evil, truth or revolution. Now, a philosophy is not a science, because its assertions cannot be empirically tested … Philosophical entities exist only insofar as they have been philosophically posited. Outside their philosophical framework, the empirical data that a philosophy organizes lose every possible unity and cohesion.
To walk, to make love, to sleep, to refrain from doing something, to give food to someone else, to eat roast beef on Friday — each is either a physical event or the absence of a physical event, or a relation between two or more physical events. However, each becomes an instance of good, bad, or neutral behavior within a given philosophical framework. Outside such a framework, to eat roast beef is radically different from making love, and making love is always the same sort of activity independent of the legal status of the partners. From a given philosophical point of view, both to eat roast beef on Friday and to make love to x can become instances of 'sin', whereas both to give food to someone and to make love to у can become instances of virtuous action.
Good or bad are theoretical stipulations according to which, by a philosophical decision, many scattered instances of the most different facts or acts become the same thing. It is interesting to remark that also the notions of 'object', 'phenomenon', or 'natural kind', as used by the natural sciences, share the same philosophical nature. This is certainly not the case of specific semiotics or of a human science such as cultural anthropology.

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

Preface to Second Edition (1843)
The Essence of Christianity (1841)

Encyclopedia of the Philosophical Sciences (1816)