Die deutsche Ideologie
In the "Grundrisse" Marx says his nature is a 'totality of needs and drives'. In "The German Ideology" he uses the formulation: 'their "needs", consequently their nature'. We can see then, that from Marx's early writing to his later work, he conceives of human nature as composed of 'tendencies', 'drives', 'essential powers', and 'instincts' to act in order to satisfy 'needs' for external objectives. For Marx then, an explanation of human nature is an explanation of the needs of humans, together with the assertion that they will act to fulfill those needs. (c.f. "The German Ideology", chapter 3). Norman Geras gives a schedule of some of the needs which Marx says are characteristic of humans: