“Science may set limits to knowledge, but should not set limits to imagination.”

“The aim of science is not to open the door to infinite wisdom, but to set some limit on infinite error.”

“Citizens, imagination usually sets the limits of the possible and the impossible; but when you have the will to do good, you must have the courage to cross these limits.”

“Who can give us the assurance that the fields already occupied by science are alone those in which knowledge is possible? Who, in the words of Galilei, is willing to set limits to the human intellect?”

“Knowledge is limited. Imagination encircles the world.”

“Your only limitations are those you set up in your mind, or permit others to set up for you.”

“Givers have to set limits because takers rarely do.”

“All things are to be examined and called into question. There are no limits set to thought.”

“After knowing that the sun neither sets nor rises except for our imaginations and the limitations of our planet Earth, there can be no more mood swings in the heart and mind.”

“Philosophy is an everlasting fire, sometimes damped down by setting itself limits, then flaring into new life as it consumes them. Every field of inquiry is limited, but philosophy has an essential relation to the question of limits, to its own limits.”