Our paper argues that economics confuses an ideal world, where human needs are apparently central, with our actual economy, where satisfying human need can at best be seen as a by‐product of a system with an entirely different and limited purpose. Marx's economics explains how the sole purpose of capitalism is to expand capital (big C), i.e. to make money. Furthermore, this limited purpose does not by happy accident trickle down to all, as Adam Smith first suggested, through production ultimately being for human consumption. Rather, the very nature of capitalist competition makes both production for production sake in boom (in the form of a build up of machinery and factory space, etc. collectively termed constant capital, little c), and cyclical destruction of capital in crises inevitable. The system is thus inherently in conflict with its own restricted purpose. Marx concludes that if human needs are to be actually met, i.e. human development is to become the central purpose of our society, we must move forward to a better form of society than capitalism. We shall consider these issues in the context of how we might save the environment, as the most basic human, or animal, need must be having a planet we can actually live on!