which is the very symbol of this ultimate nullity. When they wish to
represent eternity, they represent it by a serpent with his tail in his
mouth. There is a startling sarcasm in the image of that very
unsatisfactory meal. The eternity of the material fatalists, the
eternity of the eastern pessimists, the eternity of the supercilious
theosophists and higher scientists of to-day is, indeed, very well
presented by a serpent eating his tail, a degraded animal who destroys
even himself.

This chapter is purely practical and is concerned with what actually is
the chief mark and element of insanity; we may say in summary that it is
reason used without root, reason in the void. The man who begins to
think without the proper first principles goes mad, the man who begins
to think at the wrong end. And for the rest of these pages we have to
try and discover what is the right end. But we may ask in conclusion, if
this be what drives men mad, what is it that keeps them sane? By the end
of this book I hope to give a definite, some will think a far too
definite, answer. But for the moment it is possible in the same solely
practical manner to give a general answer touching what in actual human
history keeps men sane. Mysticism keeps men sane. As long as you have
mystery you have health; when you destroy mystery you create morbidity.
The ordinary man has always been sane because the ordinary man has
always been a mystic. He has permitted the twilight. He has always had
one foot in earth and the other in fairyland. He has always left himself
free to doubt his gods; but (unlike the agnostic of to-day) free also
to believe in them. He has always cared more for truth than for
consistency. If he saw two truths that seemed to contradict each other,
he would take the two truths and the contradiction along with them. His
spiritual sight is stereoscopic, like his physical sight: he sees two
different pictures at once and yet sees all the better for that. Thus he