The great and unlooked for discoveries that have taken place of late years have all concurred to lead many men into the opinion that we were touching on a period big with the most important changes.

The perpetual struggle for room and food.

The doctrine of population has been conspicuously absent, not because I doubt in the least its truth and vast importance, but because it forms no part of the direct problem of economics.

Population, when unchecked, goes on doubling itself every 25 years or increases in a geometrical ratio.

It accords with the most liberal spirit of philosophy to suppose that not a stone can fall, or a plant rise, without the immediate agency of divine power.

The finest minds seem to be formed rather by efforts at original thinking, by endeavours to form new combinations, and to discover new truths, than by passively receiving the impressions of other men's ideas.

It has been said, and perhaps with truth, that the conclusions of Political Economy partake more of the certainty of the stricter sciences than those of most of the other branches of human knowledge.