Relationship between constant and variable capital advanced by the capitalists. It measures the relative weight of what the capitalists advance in machinery with respect to what they advance in wages.
Organic composition of capital and the tendency of the rate of profit to fall
The tendency of the rate of profit to fall, and the parallel increase in the mass of product, come about because, in order to improve their profit, capitalists need to invest in technologies that increase their productivity. In doing so, the organic composition of capital will increase, that is, the percentage of what they advance in machinery, and the percentage of what they advance in wages will be reduced. The inevitable result is that their rate of profit (the surplus value per unit of investment) will be lower.
To compensate for the reduction in surplus value per unit produced and to obtain more surplus value, the capitalist will produce more units, that is, will increase the mass of product.
Organic composition of capital = ca / va