Invention is not the product of logical thought, even though the final product is tied to a logical structure.

Albert Einstein

Our inventions are wont to be pretty toys, which distract our attention from serious things. They are but improved means to an unimproved end.

Henry David Thoreau

Doubt is the father of invention.

Ambrose Bierce

I never did anything by accident, nor did any of my inventions come by accident; they came by work.

Thomas Alva Edison