I'm often asked what I think about as I run. Usually the people who ask this have never run long distances themselves. I always ponder the question. What exactly do I think about when I'm running? I don't have a clue.
Were this world an endless pain, and by sailing eastward we could forever reach new distances, and discover sights more sweet and strange than any Cyclades or Islands of King Solomon, then there were promise in the voyage.
Once the realization is accepted that even between the closest human beings infinite distances continue, a wonderful living side by side can grow, if they succeed in loving the distance between them which makes it possible for each to see the other whole against the sky.
The demonstration that no possible combination of known substances, known forms of machinery and known forms of force, can be united in a practical machine by which man shall fly long distances through the air, seems to the writer as complete as it is possible for the demonstration of any physical fact to be.