But what is the content of the two terms right and wrong, what actual action shall be called right and what wrong on any given occasion, may vary easily according to circumstances, according to the degree of social development and the like. There is conduct which is right at one stage of society and wrong at another, precisely because at one stage it tends to the health of society, while at another it will be bad for the health of society; just as there are ways in which it is good from time to time to train children in which it would not be well to train grown-up people; and there is conduct which is appropriate to earlier stages of society, because beneficial to society, which becomes inappropriate and harmful at any other stage. What is right and what is wrong may depend very largely upon circumstances, stage of development, spiritual receptiveness, and a host of other things; but the distinction between right and wrong itself remains unaffected by all these, and absolutely fundamental and invariable. Now, how is it that in society progress is actually made in morals? The appeal to authority can always be made in two ways. It can be made in the most obvious form in the interest of mere stagnation, by saying, "What was good enough for our fathers is good enough for us," a thing nobody ever does say; or by saying, "What is good enough for us is good enough for our children," a thing which numbers of people say. While the first form may be some safeguard against wild experiments—and wild experiments in morals are more dangerous than wild experiments anywhere else in life, for a reason I will mention in a moment—yet the tendency of this appeal is to pure stagnation. But the right appeal is to ask, not what the great men of the past actually did, but what were the principles upon which they acted. What we want to be doing with the prophets of the last generation is not saying again, like parrots, just what they said, but finding out the principles and spirit of their life and applying that same spirit to circumstances which are changed just because those prophets lived and wrought. They would not have been prophets, they would not have been great men, if they had not changed in some degree the world they lived in. Then just because they have changed the world their action may no longer be appropriate; it is not the action which they themselves would now take if they were still alive and retained their power of development. What we do then is to appeal, not to their conduct but to the principle of their conduct. So when Wilberforce started the campaign against slavery what he did was to appeal from the conduct of the Church to the principle of that conduct which it professed and admitted. In other spheres it admitted the sanctity of human personality; but it had never applied this principle to the particular problem of slavery.