Marx opens by announcing the level of abstraction he will be working with here: ‘In a general analysis of the present kind, it is assumed throughout that actual conditions correspond to their concept, or, and this amounts to the same thing, actual conditions are depicted only in so far as they express their own general type.’ Concretely, this means:
1 We shall be ignoring the fact that ‘the equalization of wages and working hours between one sphere of production and another, or between different capitals invested in the same sphere of production, comes up against all kinds of local obstacles’, for ‘frictions of this kind [...] are [...] accidental and inessential as far as the general investigation of capitalist production is concerned [...].’
2 In the previous part we saw that the rate of profit may change, even though the rate of surplus-value is constant. Here, we assume a constant rate of surplus-value.
3 In addition, we shall ignore the distinction between simple and complex labour (addressed in volume 1). ‘If the work of a goldsmith is paid at a higher rate than that of a day-labourer, for example, the former’s surplus labour also produces a correspondingly greater surplus-value than does that of the latter.’
4 We also ignore differences in wages across spheres of production and between capitals operating in the same sphere. Such differences ‘are [...] accidental and inessential as far as the general investigation of capitalist production is concerned and can therefore be ignored.’
5 We are also disinterested in differences of rates of surplus-value and profit between different countries. However,
It is clear [...] that in comparing different national rates of profit one need only combine what has been developed earlier with the arguments to be developed here. One would first consider the variation between national rates of surplus-value and then compare, on the basis of these given rates of surplus-value, how national rates of profit differ. In so far as their variation is not the result of variation in the national rates of surplus-value, it must be due to circumstances in which, as in this chapter, surplus-value is assumed to be everywhere the same, to be constant.
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