M\RXIAN POLITICAL ECONOMY 73 respectively commit the two errors mentioned in the text. See, for a good discussion, E Mandel, The Formation of Karl Marx's Economic Thought, Monthly Review 1972, and N Gerasin R Blackburn (ed.), Ideology in Social Science, Vintage, 1972. 10 Capital, vol I, p 186. 11 Ibid., p 188. 1 2 Ibid., p 193. 18 Ibid. 14 Ibid., pp 194-195. 16 A portion of the capital laid out by the capitalist in any manufacturing venture consists of course of durable machinery, called in economics 'fixed capita?. Only a fraction of the value of fixed capital enters as an element of constant capital into a single day's product. Both 'fixed5 capital and raw materials form part of constant capital, as far as the total capital laid out is concerned. For the designations 'constant9 and ^ariable^ denote ^ead* (or past) and living" labour respectively. To simplify matters, we shall assume for now that all the constant capital is used up in a single period of production, say, a day. In economic jargon, we are for now using a "circulating capital model'^, but this does not affect our results in any fundamental way. 1 ® Capital, vol I, chap X, pp 231-302. 2 7 Marxism is often misrepresented by non-Marxists as the theory that history is the product of "technology" and "institutions"- The central focus of the relationship between productive forces and relations of production, the basic determinant of history, is the class struggle. Productive forces cannot be reduced to "technology", and production relations cannot be reduced to "institutions'"*.