40

φαν35

of mental energy to be expended, even when the unnecessary
friction has been got rid of.

Every operation of the mind, however complex, has its absolutely
simple feeling, the emotion of the tout ensemble. This is a
secondary feeling or sensation excited from within the mind, just
as the qualities of outward sense are excited by something psychic
without us. It seems at first glance unaccountable that a mere
slight difference in the speed of vibration should make such a
difference of quality as that between deep vermillion and
violet blue. But then it is to be remembered that it is doubtless our
imperfect knowledge of those vibrations which has led us to represent
them abstractly as differing only in quantity. There is actually a hint
in the behaviour of electrons that a lower speed and a greater one