THE FOUNDATION OF EUGENICS. 93
would give an acceptable introduction to the newer methods employed in Biometry and in Eugenics. Further, that when read leisurely by experts in its printed form, it would give them sufficient guidance for elaborating details.
INFLUENCE OF COLLECTIVE TRUTHS
UPON INDIVIDUAL CONDUCT.
We have thus far been concerned with Probability, determined by methods that take cognizance of Variations, and yield exact results, thereby affording a solid foundation for action. But the stage on which human action takes place is a superstructure into which emotion enters, we are guided on it less by Certainties and by Probabilities than by Assurance to a greater or lesser degree. The word Assurance is derived from sure, which itself is an abbreviation of secure, that is of se- cura, or without misgiving. It is a contented attitude of mind largely dependent on custom, prejudice, or other unreasonable influences which reformers have to overcome, and some of which they are apt to utilize on their own behalf. Human nature is such that we rarely find our way by the pure light of reason, but while peering through spectacles furnished with coloured and distorting glasses.
Locke seems to confound certainty with assurance in his forcible description of the way in which men are guided in their daily
affairs (Human Understanding, iv. 14, par. i)