A quick glance at history and anthropology will ruin the idea that "human nature" is a static unchanging thing. Human nature and behaviour is partly plastic (reflections of historical and cultural conditions in relation to the specific mode of production), which is evidenced by the vast disparities in human behaviour and social organisation throughout various historical periods and geographical locations. Civil society, human behaviour and ideology have changed over time in the same way that species alter genetically over time.

Engels and Marx and others disproved these things about human nature by looking at history. Among many native nations in the Americas, there was no money. How, then, did anything get done if money is the only incentive to work? There is also a ton of evidence that humans, for millions of years, operated more or less communally, with little or no hierarchy. If it was innate "human nature," how could this be so? How could greedy humans cooperate and survive during these millions of years of scarcity if they were all so greedy and purely self-interested by nature?


I would point out that there is a massive propaganda effort to control this narrative and force it into our minds. But the real heart of the matter, that Marx would tell you, is that it is because the system (capitalism) forces those conditions upon you. In order to succeed in capitalism, it often pays off to behave greedily, and many situations arise where to not behave greedily is to fall behind and risk losing. And to lose in capitalism is to be made a debt slave, if not then to be homeless, broken, hungry, and in a word, oppressed. And here's where Marx’s ideas get really powerful. If you want to change this behaviour - to act greedily - then you need only change the system that the person is in. If you have a system (socialism), where you will always have a home, always have food, always have medical care, always have water - then there is no need to behave greedily in order to survive and have a life of dignity and purpose. Marx would argue that greed will pass from the human condition. Poverty and war too. This was Karl Marx's dangerous idea - you wouldn't just change the world, but all of humankind.