Define "full value of their labor" and explain how this is not set by the labor market.
"Surplus-value is the social product which is over and above what is required for the producers to live.
The measure of value is labour time, so surplus value is the accumulated product of the unpaid labour time of the producers. In bourgeois society, surplus value is acquired by the capitalist in the form of profit: the capitalist owns the means of production as Private Property, so the workers have no choice but to sell their labour-power to the capitalists in order to live. The capitalist then owns not only the means of production, and the workers’ labour-power which he has bought to use in production, but the product as well. After paying wages, the capitalist then becomes the owner of the surplus value, over and above the value of the workers’ labour-power.
In all societies in which there is a division of labour, there is a social surplus; what is different about bourgeois society is that surplus value takes the form of capital, and surplus value is in fact the essence of production in capitalism.– Only productive work, i.e., work which creates surplus value, is supported. All “unproductive labour” is eliminated.
The capitalists may increase the amount of surplus value extracted from the working class by two means: (1) by absolute surplus value – extending the working day as long as possible, and (2) by relative surplus value – by cutting wages.
Attempts by individual capitalists to increase their profits by introducing machinery or speeding-up production by technique fail as soon as their competitors copy the new technique and restore their market share. The end effect of these improvements in production may be to increase the productivity of labour, but unless the rate of surplus value is increased proportionately, the rate of profit will actually fall.
Having been accumulated as capital, surplus value must then be distributed to landlords, bankers and other parasites, and expended via taxes on the various expenses of maintaining the social fabic."
MIA Encyclopedia