I have just read your letter over again, and am grieved afresh at your melancholy tone about yourself. You ask why I am quiet, while you are so restless. Partly from the original constitution of things, I suppose; partly because I am less quiet than you suppose; only I once heard a proverb about a man consuming his own smoke, and I do so particularly in your presence because you, being so much more turbid, produce a reaction in me; partly because I am a few years older than you, and have not solved, but grown callous (I hear your sneer) to, many of the problems that now torture you. The chief reason is the original constitution of things, which generated me with fewer sympathies and wants than you, and also perhaps with a certain tranquil confidence in the right ordering of the Whole, which makes me indifferent in some circumstances where you would fret. Yours the nobler, mine the happier part! I think, too, that much of your uneasiness comes from that to which you allude in your letter your oscillatoriness, and your regarding each oscillation as something final as long as it lasts. There is nothing more certain than that every man’s life (except perhaps Harry Quincy’s) is a line that continuously oscillates on every side of its direction; and if you would be more confident that any state of tension you may at any time find yourself in will inevitably relieve itself, sooner or later, you would spare yourself much anxiety. I myself have felt in the last six months more and more certain that each man s constitution limits him to a certain amount of emotion and action, and that, if he insists on going under a higher pressure than normal for three months, for instance, he will pay for it by passing the next three months below par. So the best way is to keep moving steadily and regularly, as your mind becomes thus deliciously appeased (as you imagine mine to be; ah! Tom, what damned fools we are!). If you feel below par now, don t think your life is deserting you forever. You are just as sure to be up again as you are, when elated, sure to be down again. Six months, or any given cycle of time, is sure to see you produce a certain amount, and your fretful anxiety when in a stagnant mood is frivolous. The good time will come again, as it has come; and go too. I think we ought to be independent of our moods, look on them as external, for they come to us unbidden, and feel if possible neither elated nor depressed, but keep our eyes upon our work and, if we have done the best we could in that given condition, be satisfied.

William James, letter to Thomas Ward, June 8, 1866