The main defect of all hitherto-existing materialism — that of Feuerbach included — is that the Object [der Gegenstand], actuality, sensuousness, are conceived only in the form of the object [Objekts], or of contemplation [Anschauung], but not as human sensuous activity, practice [Praxis], not subjectively. Hence it happened that the active side, in opposition to materialism, was developed by idealism — but only abstractly, since, of course, idealism does not know real, sensuous activity as such. Feuerbach wants sensuous objects [Objekte], differentiated from thought-objects, but he does not conceive human activity itself as objective [gegenständliche] activity. In The Essence of Christianity [Das Wesen des Christenthums], he therefore regards the theoretical attitude as the only genuinely human attitude, while practice is conceived and defined only in its dirty-Jewish form of appearance [Erscheinungsform]. Hence he does not grasp the significance of ‘revolutionary’, of ‘practical-critical’, activity.
The question whether objective truth can be attributed to human thinking is not a question of theory but is a practical question. Man must prove the truth, i.e., the reality and power, the this-sidedness [Diesseitigkeit] of his thinking, in practice. The dispute over the reality or non-reality of thinking which is isolated from practice is a purely scholastic question.
The materialist doctrine that men are products of circumstances and upbringing, and that, therefore, changed men are products of changed circumstances and changed upbringing, forgets that it is men who change circumstances and that the educator must himself be educated. Hence this doctrine is bound to divide society into two parts, one of which is superior to society. The coincidence of the changing of circumstances and of human activity or self-change [Selbstveränderung] can be conceived and rationally understood only as revolutionary practice.
Feuerbach starts off from the fact of religious self-estrangement [Selbstentfremdung], of the duplication of the world into a religious, imaginary world, and a secular [weltliche] one. His work consists in resolving the religious world into its secular basis. He overlooks the fact that after completing this work, the chief thing still remains to be done. For the fact that the secular basis lifts off from itself and establishes itself in the clouds as an independent realm can only be explained by the inner strife and intrinsic contradictoriness of this secular basis. The latter must itself be understood in its contradiction and then, by the removal of the contradiction, revolutionised. Thus, for instance, once the earthly family is discovered to be the secret of the holy family, the former must itself be annihilated [vernichtet] theoretically and practically.
Feuerbach, not satisfied with abstract thinking, wants sensuous contemplation [Anschauung]; but he does not conceive sensuousness as practical, human-sensuous activity.
Feuerbach resolves the essence of religion into the essence of man [menschliche Wesen = ‘human nature’]. But the essence of man is no abstraction inherent in each single individual. In reality, it is the ensemble of the social relations. Feuerbach, who does not enter upon a criticism of this real essence is hence obliged:
1. To abstract from the historical process and to define the religious sentiment regarded by itself, and to presuppose an abstract — isolated - human individual.
2. The essence therefore can by him only be regarded as ‘species’, as an inner ‘dumb’ generality which unites many individuals only in a natural way.
Feuerbach consequently does not see that the ‘religious sentiment’ is itself a social product, and that the abstract individual that he analyses belongs in reality to a particular social form.
All social life is essentially practical. All mysteries which lead theory to mysticism find their rational solution in human practice and in the comprehension of this practice.
The highest point reached by contemplative [anschauende] materialism, that is, materialism which does not comprehend sensuousness as practical activity, is the contemplation of single individuals and of civil society [bürgerlichen Gesellschaft].
The standpoint of the old materialism is civil society; the standpoint of the new is human society or social humanity.
Philosophers have hitherto only interpreted the world in various ways; the point is to change it.