men and women, indeed, there are who can live on smiles and the word 'yes' forever. But for others (indeed for most), this is too tepid and relaxed a moral climate. Passive happiness is slack and insipid, and soon grows mawkish and intolerable. Some austerity and wintry negativity, some roughness, danger, stringency, and effort, some 'no! no!' must be mixed in, to produce the sense of an existence with character and texture and power. The range of individual differences in this respect is enormous; but whatever the mixture of yeses and noes may be, the person is infallibly aware when he has struck it in the right proportion for him. This, he feels, is my proper vocation, this is the optimum, the law, the life for me to live. Here I find the degree of equilibrium, safety, calm, and leisure which I need, or here I find the challenge, passion, fight, and hardship without which my soul's energy expires.
Every individual soul, in short, like every individual machine or organism, has its own best conditions of efficiency. A given machine will run best under a certain steam-pressure, a certain amperage; an organism under a certain diet, weight, or exercise. You seem to do best, I heard a doctor say to a patient, at about 140 millimeters of arterial tension. And it is just so with our sundry souls: some are happiest in calm weather; some need the sense of tension, of strong volition, to make them feel alive and well. For these latter souls, whatever is gained from day to day must be paid for by sacrifice and inhibition, or else it comes too cheap and has no zest.
Now when characters of this latter sort become religious, they are apt to turn the edge of their need of effort and negativity against their natural self; and the ascetic life gets evolved as a consequence.
When Professor Tyndall in one of his lectures tells us
