Conclusion. Correlation of the Tendencies to Increasing and to Diminishing Return

At the beginning of the Book we saw how the extra return of raw produce which nature affords to an increased application of capital and labour, other things being equal, tends in the long run to diminish. In the remainder of the Book and especially in the last four chapters we have looked at the other side of the shield, and seen how man’s power of productive work increases with the volume of the work that he does. Considering first the causes that govern the supply of labour, we saw how every increase in the physical, mental and moral vigour of a people makes them more likely, other things being equal, to rear to adult age a large number of vigorous children. Turning next to the growth of wealth, we observed how every increase of wealth tends in many ways to make a greater increase more easy than before. And lastly we saw how every increase of wealth and every increase in the numbers and intelligence of the people increased the facilities for a highly developed industrial organization, which in its turn adds much to the collective efficiency of capital and labour.