Page:Reason in Common Sense (1920).djvu/285

 self-knowledge. They would be tentative only, and human nature would be freely admitted to be as variable, as relative, and as transitory as the natural history of the universe might make it.

The error, however, would be profound and the contradiction hopeless if we should deny the ideal authority of human nature because we had discovered its origin and conditions. Nature and evolution, let us say, have brought life to the present form; but this life lives, these organs have determinate functions, and human nature, here and now, in relation to the ideal energies it unfolds, is a fundamental essence, a collection of activities with determinate limits, relations, and ideals. The integration and determinateness of these faculties is the condition for any synthetic operation of reason. As the structure of the steam-engine has varied greatly since its first invention, and its attributions have increased, so the structure of human nature has undoubtedly varied since man first appeared upon the earth; but as in each steam-engine at each moment there must be a limit of mobility, a unity of function and a clear determination of parts and tensions, so in human nature, as found at any time in any man, there is a definite scope by virtue of which alone he can have a reliable memory, a recognisable character, a faculty of connected thought and speech, a social utility, and a moral ideal. On man’s given structure, on his activity hovering about fixed objects, depends the