In Section II our author sets out to find what answers have been given to her problem. The analysis she has in mind is now broader than the strict confines of the arithmetical model. Technical progress is going on, and the output of an hour's labour rises as time goes by. (The concept of _value_ now becomes treacherous, for the _value_ of commodities is continuously falling.) Real wages tend to be constant in terms of commodities, thus the _value_ of labour power is falling, and the share of surplus in net income is rising (_s/v_, the rate of exploitation, is rising). The amount of saving in real terms is therefore rising (she suggests later that the proportion of surplus saved rises with surplus, in which case real savings increase all the more[33]). The problem is thus more formidable than appears in the model, for the equilibrium rate of accumulation of capital, in real terms, is greater than in the model, where the rate of exploitation is constant. At the same time the proportion of constant to variable capital is rising. She regards this not as something which is likely to happen for technical reasons, but as being necessarily bound up with the very nature of technical progress. As productivity increases, the amount of producers' goods handled per man-hour of labour increases; therefore, she says, the proportion of _c_ to _v_ must increase.[34] This is an error. It arises from thinking of constant capital in terms of goods, and contrasting it with variable capital in terms of _value_, that is, hours of labour. She forgets Marx's warning that, as progress takes place, the _value_ of the commodities making up constant capital also falls.[35] It is perfectly possible for productivity to increase without any increase in the _value_ of capital per man employed. This would occur if improvements in the productivity of labour in making producers' goods kept pace with the productivity of labour in using producers' goods to make consumers' goods (capital-saving inventions balance labour-saving inventions, so that technical progress is 'neutral'). However, we can easily get out of this difficulty by postulating that as a matter of fact technical progress is mainly labour-saving, or, a better term, capital-using, so that capital per man employed is rising through time.