Here Marx says philosophy serves history , as academic disciplines

"It is, therefore, the task of history, once the other-world of truth has vanished, to establish the truth of this world. It is the immediate task of philosophy, which is in the service of history, to unmask self-estrangement in its unholy forms once the holy form of human self-estrangement has been unmasked. Thus, the criticism of Heaven turns into the criticism of Earth, the criticism of religion into the criticism of law, and the criticism of theology into the criticism of politics."

https://www.marxists.org/archive/marx/works/1843/critique-hpr/intro.htm

"The modern ancien régime is rather only the comedian of a world order whose true heroes are dead. History is thorough and goes through many phases when carrying an old form to the grave. The last phases of a world-historical form is its comedy. The gods of Greece, already tragically wounded to death in Aeschylus’s tragedy Prometheus Bound, had to re-die a comic death in Lucian’s Dialogues. Why this course of history? So that humanity should part with its past cheerfully. This cheerful historical destiny is what we vindicate for the political authorities of Germany."




"The weapon of criticism cannot, of course, replace criticism of the weapon, material force must be overthrown by material force; but theory also becomes a material force as soon as it has gripped the masses. Theory is capable of gripping the masses as soon as it demonstrates ad hominem, and it demonstrates ad hominem as soon as it becomes radical. To be radical is to grasp the root of the matter. But, for man, the root is man himself. The evident proof of the radicalism of German theory, and hence of its practical energy, is that is proceeds from a resolute positive abolition of religion. The criticism of religion ends with the teaching that man is the highest essence for man – hence, with the categoric imperative to overthrow all relations in which man is a debased, enslaved, abandoned, despicable essence, relations which cannot be better described than by the cry of a Frenchman when it was planned to introduce a tax on dogs: Poor dogs! They want to treat you as human beings!"

"In the present struggle it saw only the critical struggle of philosophy against the German world; it did not give a thought to the fact that philosophy up to the present itself belongs to this world and is its completion, although an ideal one. Critical towards its counterpart, it was uncritical towards itself when, proceeding from the premises of philosophy, it either stopped at the results given by philosophy or passed off demands and results from somewhere else as immediate demands and results of philosophy – although these, provided they are justified, can be obtained only by the negation of philosophy up to the present, of philosophy as such. We reserve ourselves the right to a more detailed description of this section: It thought it could make philosophy a reality without abolishing [aufzuheben] it."

Charles Brown : In _Ludwig Feuerbach_ Engels carries out a negation of philosophy

"Where, then, is the positive possibility of a German emancipation? Answer: In the formulation of a class with radical chains, a class of civil society which is not a class of civil society, an estate which is the dissolution of all estates, a sphere which has a universal character by its universal suffering and claims no particular right because no particular wrong, but wrong generally, is perpetuated against it; which can invoke no historical, but only human, title; which does not stand in any one-sided antithesis to the consequences but in all-round antithesis to the premises of German statehood; a sphere, finally, which cannot emancipate itself without emancipating itself from all other spheres of society and thereby emancipating all other spheres of society, which, in a word, is the complete loss of man and hence can win itself only through the complete re-winning of man. This dissolution of society as a particular estate is the proletariat. The proletariat is beginning to appear in Germany as a result of the rising industrial movement. For, it is not the naturally arising poor but the artificially impoverished, not the human masses mechanically oppressed by the gravity of society, but the masses resulting from the drastic dissolution of society, mainly of the middle estate, that form the proletariat, although, as is easily understood, the naturally arising poor and the Christian-Germanic serfs gradually join its ranks.

By heralding the dissolution of the hereto existing world order, the proletariat merely proclaims the secret of its own existence, for it is the factual dissolution of that world order. By demanding the negation of private property, the proletariat merely raises to the rank of a principle of society what society has raised to the rank of its principle, what is already incorporated in it as the negative result of society without its own participation. The proletarian then finds himself possessing the same right in regard to the world which is coming into being as the German king in regard to the world which has come into being when he calls the people his people, as he calls the horse his horse. By declaring the people his private property, the king merely proclaims that the owner of property is king. As philosophy finds its material weapon in the proletariat, so the proletariat finds its spiritual weapon in philosophy. And once the lightning of thought has squarely struck this ingenuous soil of the people, the emancipation of the Germans into men will be accomplished.

Let us sum up the result: The only liberation of Germany which is practically possible is liberation from the point of view of that theory which declares man to be the supreme being for man. Germany can emancipate itself from the Middle Ages only if it emancipates itself at the same time from the partial victories over the Middle Ages. In Germany, no form of bondage can be broken without breaking all forms of bondage. Germany, which is renowned for its thoroughness, cannot make a revolution unless it is a thorough one. The emancipation of the German is the emancipation of man. The head of this emancipation is philosophy, its heart the proletariat. Philosophy cannot realize itself without the transcendence [Aufhebung] of the proletariat, and the proletariat cannot transcend itself without the realization [Verwirklichung] of philosophy.

When all the inner conditions are met, the day of the German resurrection will be heralded by the crowing of the cock of Gaul. "