A simple numerical example will help to understand why the contribution of the Residual is so large relative to that of capital. Let us take L = l-5% per year, K = 3-0%, while a and J3 are 75 and 25% respectively, as suggested more or less by the aggregate American data. In the absence of the Residual, Y would be a weighted mean of L and K, and since labour’s weight is much larger than capital’s, F would be much closer to L than to K: equalling in our example 1-9%. Actually Y has approximated 3-5%, and the difference between 3-5 and 1 -9% yields an A of 1 -6%. The rate of growth of output per unit of labour input being 2% (3-5— 1-5), the ratio of A to the latter is 80%, a figure not far from Solow’s 87%. With a weight of only 25% (more or less) there is not much that capital can do. Even if Kshould double, other variables remaining the same, Y would increase only from 3-5 to 4-2%,of A is completely divorced from investment and capital accumulation. Capital merely accumulates; it does not change its quality, form or composition; it does not serve as the instrument for the introduction of technical change into the productive process. It is this kind of capital accumulation (wooden ploughs piled up on the top of existing wooden ploughs) that contributes so little to economic growth.