 Socialism is best defined in contrast with capitalism, as socialism has arisen both as a critical challenge to capitalism, and as a proposal for overcoming and replacing it. In the classical, Marxist definition (G.A. Cohen 2000a: ch.3; Fraser 2014: 57–9), capitalism involves certain relations of production. These comprise certain forms of control over the productive forces—the labor power that workers deploy in production and the means of production such as natural resources, tools, and spaces they employ to yield goods and services—and certain social patterns of economic interaction that typically correlate with that control. Capitalism displays the following constitutive features: