In addition to straining the machine by our excessive anxiety for the spread of truth, we give a very great deal too much attention to the state of other people’s machines.  I cannot too strongly, too sarcastically, deprecate this astonishing habit.  It will be found to be rife in nearly every household and in nearly every office.  We are most of us endeavouring to rearrange the mechanism in other heads than our own.  This is always dangerous and generally futile.  Considering the difficulty we have in our own brains, where our efforts are sure of being accepted as well-meant, and where we have at any rate a rough notion of the machine’s construction, our intrepidity in adventuring among the delicate adjustments of other brains is remarkable.  We are cursed by too much of the missionary spirit.  We must needs voyage into the China of our brother’s brain, and explain there that things are seriously wrong in that heathen land, and make ourselves unpleasant in the hope of getting them put right.  We have all our own brain and body on which to wreak our personality, but this is not enough; we must extend our personality further, just as though we were a colonising world-power intoxicated by the idea of the ‘white man’s burden.’

One of the central secrets of efficient daily living is to leave our daily companions alone a great deal more than we do, and attend to ourselves.  If a daily companion is conducting his life upon principles which you know to be false, and with results which you feel to be unpleasant, the safe rule is to keep your mouth shut.  Or if, out of your singular conceit, you are compelled to open it, open it with all precautions, and with the formal politeness you would use to a stranger.  Intimacy is no excuse for rough manners, though the majority of us seem to think it is.  You are not in charge of the universe; you are in charge of yourself.  You cannot hope to manage the universe in your spare time, and if you try you will probably make a mess of such part of the universe as you touch, while gravely neglecting yourself.  In every family there is generally some one whose meddlesome interest in other machines leads to serious friction in his own.  Criticise less, even in the secrecy of your chamber.  And do not blame at all.  Accept your environment and adapt yourself to it in silence, instead of noisily attempting to adapt your environment to yourself.  Here is true wisdom.  You have no business trespassing beyond the confines of your own individuality.  In so trespassing you are guilty of impertinence.  This is obvious.  And yet one of the chief activities of home-life consists in prancing about at random on other people’s private lawns.  What I say applies even to the relation between parents and children.  And though my precept is exaggerated, it is purposely exaggerated in order effectively to balance the exaggeration in the opposite direction.