Crack-brained meddling by the authorities [can] aggravate an existing crisis.

All social life is essentially practical. All mysterious which lead theory to mysticism find their rational solution in human practice and in the comprehension of the practice.

The development of civilization and industry in general has always shown itself so active in the destruction of forests that everything that has been done for their conservation and production is completely insignificant in comparison.

Surplus-value and the rate of surplus-value are... the invisible essence to be investigated, whereas the rate of profit and hence the form of surplus-value as profit are visible surface phenomena

...the French Revolution gave rise to ideas which led beyond the ideas of the entire old world order. The revolutionary movement which began in 1789... gave rise to the communist idea which Babeuf's friend Buonarroti re-introduced in France after the Revolution of 1830. This idea, consistently developed, is the idea of the new world order.

We should not say that one man's hour is worth another man's hour, but rather that one man during an hour is worth just as much as another man during an hour. Time is everything, man is nothing: he is at the most time's carcass.

The rule of the bourgeois democrats [in pre-federal Germany], from the very first, will carry within it the seeds of its own destruction