WHAT modern people want to be made to understand is simply that all argument begins with an assumption; that is, with something that you do not doubt. You can, of course, if you like, doubt the assumption at the beginning of your argument, but in that case you are beginning a different argument with another assumption at the beginning of it. Every argument begins with an infallible dogma, and that infallible dogma can only be disputed by falling back on some other infallible dogma; you can never prove your first statement or it would not be your first. All this is the alphabet of thinking... And it has this special and positive point about it, that it can be taught in a school, like the other alphabet. Not to start an argument without stating your postulates could be taught in philosophy as it is taught in Euclid, in a common schoolroom with a blackboard. And I think it might be taught in some simple and rational degree even to the young, before they go out into the streets and are delivered over entirely to the logic and philosophy of the Daily Mail.
Much of our chaos about religion and doubt arises from this—that our modern sceptics always begin by telling us what they do not believe. But even in a sceptic we want to know first what he does believe. Before arguing, we want to know what we need not argue about. And this confusion is infinitely increased by the fact that all the sceptics of our time are sceptics at different degrees of the dissolution of scepticism. ...
Now you and I have, I hope, this advantage over all those clever new philosophers, that we happen not to be mad. All of us believe in St Paul's Cathedral; most of us believe in St Paul. But let us clearly realize this fact, that we do believe in a number of things which are part of our existence, but which cannot be demonstrated. Leave religion for the moment wholly out of the question. All sane men, I say, believe firmly and unalterably in a certain number of things which are unproved and unprovable. Let us state them roughly.
(1) Every sane man believes that the world around him and the people in it are real, and not his own delusion or dream. No man starts burning London in the belief, that his servant will soon wake him for breakfast. But that I, at any given moment, am not in a dream, is unproved and unprovable. That anything exists except myself is unproved and unprovable.
(2) All sane men believe that this world not only exists, but matters. Every man believes there is a sort of obligation on us to interest ourselves in this vision or panorama of life. He would think a man wrong who said, "I did not ask for this farce and it bores me. I am aware that an old lady is being murdered down stairs, but I am going to sleep." That there is any such duty to improve the things we did not make is a thing unproved and unprovable.
(3) All sane men believe that there is such a thing as a self or ego, which is continuous. There is no inch of my brain matter the same as it was ten years ago. But if I have saved a man in battle ten years ago, I am proud; if I have run away, I am ashamed. That there is such a paramount "I" is unproved and unprovable. But it is more than unproved and unprovable; it is definitely disputed by many metaphysicians.
(4) Lastly, most sane men believe, and all sane men in practice assume, that they have a power of choice and responsibility for action....
Surely it might be possible to establish some plain, dull statement such as the above, to make people see where they stand. And if the youth of the future must not (at present) be taught any religion, it might at least be taught, clearly and firmly, the three or four sanities and certainties of human free thought.
~G.K. Chesterton: Daily News, June 22nd, 1907
Collected in The Man Who Was Orthodox: a Selection from the Uncollected Writings of G. K. Chesterton. A. L. Maycock (Editor)