If consciousness could ever have the function of guiding conduct better than instinct can, in the beginning it would be most incompetent for that office. Only the routine and equilibrium which healthy instinct involves keep thought and will at all within the limits of sanity. The predetermined interests we have as animals fortunately focus our attention on practical things, pulling it back, like a ball with an elastic cord, within the radius of pertinent matters. Instinct alone compels us to neglect and seldom to recall the irrelevant infinity of ideas. Philosophers have sometimes said that all ideas come from experience; they never could have been poets and must have forgotten that they were ever children. The great difficulty in education is to get experience out of ideas. Shame, conscience, and reason continually disallow and ignore what consciousness presents; and what are they but habit and latent instinct asserting themselves and forcing us to disregard our midsummer madness? Idiocy and lunacy are merely reversions to a condition in which present consciousness is in the ascendant and has escaped the control of unconscious forces. We speak of people being “out of their senses,” when they have in fact fallen back into them; or of those who have “lost their mind,” when they have lost merely that habitual control over consciousness which prevented it from flaring into all sorts of obsessions and agonies. Their bodies having become deranged, their minds, far from correcting that derangement, instantly share and betray it. A dream is always simmering below the conventional surface of speech and reflection. Even in the highest reaches and serenest meditations of science it sometimes breaks through. Even there we are seldom constant enough to conceive a truly natural world; somewhere passionate, fanciful, or magic elements will slip into the scheme and baffle rational ambition. A body seriously out of equilibrium, either with itself or with its environment, perishes outright. Not so a mind. Madness and suffering can set themselves no limit; they lapse only when the corporeal frame that sustains them yields to circumstances and changes its habit. If they are unstable at all, it is because they ordinarily correspond to strains and conjunctions which a vigorous body overcomes, or which dissolve the body altogether. A pain not incidental to the play of practical instincts may easily be recurrent, and it might be perpetual if even the worst habits were not intermittent and the most useless agitations exhausting. Some respite will therefore ensue upon pain, but no magic cure. Madness, in like manner, if pronounced, is precarious, but when speculative enough to be harmless or not strong enough to be debilitating, it too may last for ever.