'Der Kopf ist rund damit das Denken die Richtung wechseln kann'

Our heads are round so that our thinking can change direction.

-Francis Picabia
(dadaist and surrealist)

For having lived long, I have experienced many instances of being obliged, by better information or fuller consideration, to change opinions, even on important subjects, which I once thought right but found to be otherwise.

-Benjamin Franklin
(pretty smart guy)