The coincidence of the changing of circumstances and of human activity can be conceived and rationally understood only as revolutionary practice.
Feuerbach starts out from the fact of religious self-estrangement, of the duplication of the world into a religious, imaginary world and a real 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 stil remains to be done.
Isolated from practice, the controversy over the reality or unreality of thinking is a purely scholastic question.
The materialist doctrine that humans are products of circumstances and upbringing and that, therefore, men who change are products of new circumstances and a different upbringing, forgets that circumstances are changed by men themselves, and that it is essential to educate the educator.
Feuerbach wants sensuous objects, clearly distinguished from mental objects, but he does not conceive human activity in terms of subject and object.
That is why, in The Essence of Christianity, he regards only theoretical activity as authentically human, whilst practice is conceived and defined only in its dirty Jewish manifestation.
But the fact that the secular basis detaches from itself and fixes in the clouds as an independent realm can be explained only by the self-negation and self-contradiction within it.
This must be first of all understood in the context of its contradictions, and then be revolutionised by the removal of those contradictions.