When the fabric of society is so rigid that it cannot change quickly enough, adjustments are achieved by social unrest and revolutions.

Knowledge acquired in biological research is seldom directly applicable to human beings ... The results of scientific research, obtained under these conditions, cannot be applied directly to human beings who vary widely in their hereditary make-up, in their environment, and in their past health record.

When the Industrial Revolution of the nineteenth century brought a rapid increase in wealth, the demand of workers for a fair share of the wealth they were creating was conceded only after riots and strikes.

Our civilization has evolved through the continuous adjustment of society to the stimulus of new knowledge.

In recent times, European nations, with the use of gunpowder and other technical improvements in warfare, controlled practically the whole world. One, the British Empire, brought under one government a quarter of the earth and its inhabitants.

If the views I have expressed be right, we can think of our civilization evolving with the growth of knowledge from small wandering tribes to large settled law.

Some wars have been due to the lust of rulers for power and glory, or to revenge to wipe out the humiliation of a former defeat.