"We like to picture to ourselves the field of law as accurately mapped and plotted. We draw our little lines, and they are hardly down before we blur them. As in time and space, so here. Divisions are working hypotheses, adopted for convenience. … So also the duty of a judge becomes itself a question of degree, and he is a useful judge or a poor one as he estimates the measure accurately or loosely. He must balance all his ingredients, his philosophy, his logic, his analogies, his history, his customs, his sense of right, and all the rest, and adding a little here and taking out a little there, must determine, as wisely as he can, which weight shall tip the scales."