It is easy to see that the moral sphere is not cut off from the physical plane. Take the example of an alcoholic.
To begin with, he was a noble, considerate, generous and cultured man; he had every desirable quality. But as soon as he began to drink, those qualities were blunted and eventually disappeared.
He became coarse, selfish and brutal. What had changed? The moral side of him, his behaviour.
It was all lost because he drank too much. Or take another example, that of a man who is so addicted to gambling that he ends by neglecting all his obligations and his duty to his wife and family.
To begin with, his gambling had nothing to do with moral considerations. Playing cards is a wholly innocuous activity, and yet it was the moral sphere that eventually suffered the ill effects.
How can anyone fail to see the link between the moral and physical spheres?