According to Luxemburg, Marx had made an error in Capital in that the proletariat could not afford to buy the commodities they produced, and therefore by his own criteria it was impossible for capitalists to make a profit in a closed-capitalist system since the demand for commodities would be too low, and therefore much of the value of commodities could not be transformed into money.
De acordo con Luxemburgo, Marx tivo un erro en Capital en que o proletariado non podería chegar a mercar os produtos que fabricaba, e por iso segundo o seu criterio era imposible para os capitalistas obter un beneficio nun sistema capitalista pechado, xa que a demanda de produtos sería demasiado baixa, e polo tanto gran parte da produción non podería ser transformada en diñeiro.