"Living political constitutions must be Darwinian in structure and in practice. Society is a living organism and must obey the laws of life, not of mechanics; it must develop. All that progressives ask or desire is permission-in an era when 'development,' 'evolution,' is the scientific word-to interpret the Constitution according to the Darwinian principle; all they ask is recognition of the fact that a nation is a living thing and not a machine."