on the ability of the economy to grow. The more the interest and rent that must be paid for production to occur, the more this becomes a constraint for expanding production. If the population increases, output, investments, and jobs necessarily have to grow to keep up with it; but in a complex system of financial intermediation involving rent seeking, economic growth may fail to occur on a sufficient scale, and in that case, some groups can only improve their economic position at the expense of others. This argument, however, is also disputed by many theorists; the objection is simply that well-developed capital and money markets ensure that the finance exists to develop production, and that without a strong financial sector, production would be starved of funds. Non-capitalist economic areas. In his theory of capital, Marx failed to consider the importance and weight of the non-capitalist production activities that must occur to sustain capitalist production (a significant component of which is household labour; see below). He was primarily concerned to show that the reproduction of society as a whole could in principle be accomplished by means of the accumulation of capital. All the activities of economic production can, Marx argued, in principle be organized in a capitalist way (according to commercial logic). It supplied proof that the capitalist mode of production could exist as an historically distinctive world system, completely dominated by the requirements of capital, without quickly breaking down. But this idea was strongly criticized, especially by German Marxist authors such as Rosa Luxemburg and Fritz Sternberg. They argued that capital accumulation proceeds only by constantly drawing upon a non-capitalist "hinterland" or region. That is, markets can expand only if there are new, non-capitalist areas to expand into; but inversely, these non-capitalist areas could actually support the capitalist economy well in advance of becoming thoroughly organized according to commercial principles. Many Marxists have demonstrated the mistake(s) of Luxemburg in misunderstanding Marx's reproduction Schema. In Limits to Capital and In Nature, Difference and the Geography of Justice, David Harvey finds that a closed capitalist system could balance the various factors of production and successful expanded reproduction (without recourse to non-capitalist, or other "outside" factors)is possible. Whilst rejecting the necessity of expanding into non-capitalist areas for successful accumulation to take place, Harvey does recognize that in neoliberalism the privatization of the public sector, including partial privatization via P3s, as well as outsourcing,