John Cassidy's redefinition of Marx as a "student of capitalism" is wide of the mark ("The next big thinker", Review, 7 December). Marx didn't write Capital to satisfy intellectual curiosity. He did so out of a recognition that once capitalism had passed its early dynamic phase it would throw up constraints on human development. Modern thinkers who adopt Marx do so because they want to understand the dynamics of capitalist society and that is generally where their interest ends. In this age of low horizons, radical social change brought about by conscious action is off the agenda, and in this climate Marx can seem unthreatening. However, Marx wasn't interested in just understanding society, in his words "the point is to change it".

David Amis

Stanford le Hope, Essex