I, then a young and omniscient student (alas, I was soon to lose both these virtues)... - Leszek Kołakowski

Culture, when it loses its sacred sense, loses all sense. With the disappearance of the sacred, which imposed limits to the perfection which could be attained by the profane, arises one of the most dangerous illusions of our civilization—the illusion that there are no limits to the changes that human life can undergo, that society is 'in principle' an endlessly flexible thing, and that to deny this flexibility and this perfectibility is to deny man's total autonomy and thus to deny man himself.

In 1903 there appeared Problems of Idealism, a collection of essays many of whose authors had recently been Marxists, but which condemned Marxism and materialism for their moral nihilism, contempt of personality, determinism, and fanatical pursuit of social values regardless of the individuals who made up society; they also attacked Marxism for its uncritical worship of progress and sacrifice of the present to the future. (pp. 420-1)

In this sense Marxism performs the function of a religion, and its efficacy is of a religious character. But it is a caricature and a bogus form of religion, since it presents its temporal eschatology as a scientific system, which religious mythologies do not purport to be.