> If a man sees a river run downhill day after day and year after year, he is justified in reckoning, we might say in betting, that it will do so till he dies.

> If a man sees a river run downhill day after day and year after year, he is justified in reckoning, we might say in betting, that it will do so till he dies. But he is not justified in saying that it cannot run uphill, until he really knows why it runs downhill. To say it does so by gravitation answers the physical but not the philosophical question. It only repeats that there is a repetition; it does not touch the deeper question of whether that repetition could be altered by anything outside it. And that depends on whether there <is> anything outside it. For instance, suppose that a man had only seen the river in a dream. He might have seen it in a hundred dreams, always repeating itself and always running downhill. But that would not prevent the hundredth dream being different and the river climbing the mountain; because the dream is a dream, and there <is> something outside it. - G. K. Chesterton "The Revival of Philosohy - Why?" https://www.chesterton.org/the-revival-of-philosophy-why/ https://www.chesterton.org/the-revival-of-philosophy-why/