If we worked on the assumption that what is accepted as true really is true, then there would be little hope for advance

If we all worked on the assumption that what is accepted as true is really true, there would be little hope of advance.

No flying machine will ever fly from New York to Paris.

The airplane stays up because it doesn't have the time to fall.

"If birds can glide for long periods of time, then… why can’t I ?”

No flying machine will ever fly from New York to Paris ... [because] no known motor can run at the requisite speed for four days without stopping.