
He argued that philosophy had been describing the world when it should be changing it — and then described it more precisely than almost anyone.
Marx was educated in philosophy and law, wrote his doctoral thesis on Epicurus, and then spent the rest of his life arguing that philosophy had been describing the world when it should be changing it. His early work reads like philosophy: the alienated worker, the commodity as fetish, labor as the expression of human essence. His mature work reads like science: capitalism as a system with a logic of its own, surplus value, the tendency of the rate of profit to fall, historical materialism as the method. He was wrong about some predictions and right about others, and those judgments change with each decade. What survives judgment entirely is the description: the reduction of human relations to exchange value, the power of economic structure to shape thought, the systematic analysis of who benefits from what arrangement. That lens is now basic equipment, used by people who have never opened Capital.

“Philosophers have only interpreted the world, in various ways. The point, however, is to change it.”
“The history of all hitherto existing society is the history of class struggles.”
Expelled from France and then Belgium, Marx arrived in London in 1849 and never left. He lived in poverty in Soho, dependent on Engels's factory income, and spent his mornings at the British Museum reading room working on Capital. The reading room became his second home for thirty years.
Das Kapital appeared in Hamburg in 1867. Marx had been working on the theory of political economy since the 1840s; the final book was a fraction of a vast projected work. He spent the rest of his life revising volumes two and three, which remained unfinished at his death and were edited and published by Engels.
Marx stood Hegel on his head: the Hegelian dialectic of ideas became the materialist dialectic of economic forces. He kept the logic of contradiction and development while replacing Spirit with the labor of actual human beings.
Marx found Feuerbach's unmasking of religion as human projection liberating before writing his brief, blistering Theses on Feuerbach, arguing that Feuerbach never asked what economic conditions made humans need such projections in the first place.
Fanon extended Marxist analysis of alienation and class to the specific situation of colonialism: the colonized person is not merely exploited economically but psychologically unmade. The struggle is for consciousness, not just conditions.
Dussel's close readings of Marx's late notebooks, especially the Grundrisse, fed directly into his philosophy of liberation, which extends Marx's critique of exploitation to argue that the wealth of Europe's center depended on the violent extraction of Latin America's periphery.
Marx and Engels co-wrote The Communist Manifesto and sustained a lifelong intellectual and financial partnership; Engels's income from the family mill supported Marx for decades, and Engels spent his final years completing Capital from Marx's incomplete manuscripts after his friend's death.