A well-trained mind is like a well-trained dog: it’s unobtrusive, doesn’t deviate, looks straight ahead, has one master.
Every man has two servants: Mind and Body.
For heaven’s sake, man, these are not your enemies; they are as loveable as Labs. But look, even Labs have to be trained! Otherwise, you’ve got a great, slobbering mess on your hands—a bipedal appetite, humping everything perpendicular, baying to the moon about profit and loss.
Of course, you cannot put Mind and Body on a leash. Tutored men employ the Austerities. Slowly, inevitably, Mind and Body are led to the understanding that the reason they exist is to express the highest qualities of the governing body. They get that. They love that.
A man lives intelligently and well who has control over his servants. A man lives poorly and penuriously who is controlled by them.
Some men have considerable control over one of their servants but limited or no control over the other. These men tend either to lethargy or hyper-activity. Many of the latter group are assailed by regret and acquire religion as a means of expiation. (It doesn’t work.)