From the grand curve of our earth it could easily be inferred that every inch of it was thus curved.

It would seem rational that as a man has a brain on both sides, he should have a heart on both sides.

Yet scientific men are still organizing expeditions to find the North Pole, because they are so fond of flat country.

Scientific men are also still organising expeditions to find a man's heart; and when they try to find it, they generally get on the wrong side of him.
Now, actual insight or inspiration is best tested by whether it guesses these hidden malformations or surprises.

If our mathematician from the moon saw the two arms and the two ears, he might deduce the two shoulder-blades and the two halves of the brain.