Religion is the sigh of the oppressed creature, the heart of a heartless world, and the soul of soulless conditions. It is the opium of the people.
It is absolutely impossible to transcend the laws of nature. What can change in historically different circumstances is only the form in which these laws expose themselves.
In bourgeois society capital is independent and has individuality, while the living person is dependent and has no individuality.
In a higher phase of communist society... only then can the narrow horizon of bourgeois right be fully left behind and society inscribe on its banners: from each according to his ability, to each according to his needs.
Landlords, like all other men, love to reap where they never sowed.
Natural science will in time incorporate into itself the science of man, just as the science of man will incorporate into itself natural science: there will be one science.
Medicine heals doubts as well as diseases.
Nothing can have value without being an object of utility.
On a level plain, simple mounds look like hills; and the insipid flatness of our present bourgeoisie is to be measured by the altitude of its great intellects.
Reason has always existed, but not always in a reasonable form.
Religion is the impotence of the human mind to deal with occurrences it cannot understand.
History repeats itself, first as tragedy, second as farce.
Religion is the opium of the masses.
History does nothing; it does not possess immense riches, it does not fight battles. It is men, real, living, who do all this.