The society should be divided into four classes of men. That is natural. Just like in your body there are four divisions: the head division, the arm division, the belly division and the leg division. You cannot avoid it. If you simply say that, "I shall keep my head only," that is not possible. If you say that, "I should keep my legs only," no, that will not do. If you say that "I shall keep my hands only," no, that will not do.
You must keep the whole things—the head, the arms and the belly and the legs. Then your body is a healthy condition and will work very nicely. When you have to do something, you have to tax your brain. That is the business of the brain. When you have to protect yourself, your hands will be required. If somebody comes to attack you, you immediately expand your hand or take some weapon to protect yourself. So this is necessary. And when you want to digest food, the belly is required. Because without digesting food, where shall you get the strength? That is also required. And when you want to move, the legs are required.