Percy Nunn

"Every scheme of education being, at bottom, a practical philosophy, necessarily touches life at every point. Hence any educational aims which are concrete enough to give definite guidance are correlative to ideals of life—and, as ideals of life are eternally at variance, their conflict will be reflected in educational theories."

"... the as a substitute for is a law about the metrical properties of space around the "attracting" mass. Since it is to have universal validity, it must be a mathematical formula whose form is preserved when it is transformed from any one system of coordinates to any other; and since each system has its own time-measure as well as its own space-measures, time as well as space must be involved in the metrical properties with which the law deals."