Pain (n.) is the positive element in life, and pleasure its negation.
Pain (n.) of any great sort, of mind or body, reveals what we deserve, because it could not have befallen us unless we did.
Pain (n.) is not an idea but an immediate affection of the will: any impression on the body that goes against it.
Pain (n.) can only change its form: drive it out as want and it returns as lust, love, jealousy, envy, hatred, ambition, sickness; failing all else it comes in the sad grey garments of boredom.
Pain (n.) grows with consciousness: the plant feels none, insects little, vertebrates much, man most — and among men the genius suffers most of all; he that increaseth knowledge increaseth sorrow.
Pain (n.) of body and pain of mind cancel each other: great bodily pain makes us indifferent to every other trouble, and great mental anguish makes bodily pain a welcome distraction — which is why suicide becomes easy.