"At a certain stage of their development, the material productive forces of society come in conflict with the existing relations of production or – what is but a legal expression for the same thing – with the property relations within which they have been at work hitherto."From forms of development of the productive forces these relations turn into fetters. Then begins an epoch of social revolution."
"We ought to regard the present state of the universe as the effect of its antecedent state and as the cause of the state that is to follow."An intelligence knowing all the forces acting in nature at a given instant, as well as the momentary positions of all things in the universe, would be able to comprehend in one single formula the motions of the largest bodies as well as the lightest atoms in the world, provided that its intellect were sufficiently powerful to subject all data to analysis; to it nothing would be uncertain, the future as well as the past would be present to its eyes."The perfection that the human mind has been able to give to astronomy affords but a feeble outline of such an intelligence."
"People come to think what they must think when they must think it."