We do not know, in most cases, how far social failure and success are due to heredity, and how far to environment. But environment is the easier of the two to improve.

The idea of protoplasm, which was really a name for our ignorance, [is] only a little less misleading than the expression "Vital force".

To the biologist the problem of socialism appears largely as a problem of size.

The wise man regulates his conduct by the theories both of religion and science. But he regards these theories not as statements of ultimate fact but as art-forms.

An attempt to study the evolution of living organisms without reference to cytology would be as futile as an account of stellar evolution which ignored spectroscopy.

Reality is the cage of those who lack imagination.

Capitalism, though it may not always give the scientific worker a living wage, will always protect him, as being one of the geese which produce golden eggs for its table.