Entire ignorance is not so terrible or extreme an evil, and is far from being the greatest of all too much cleverness and too much learning, accompanied with ill bringing-up, are far more fatal. – Plato

The learning and knowledge that we have, is, at the most, but little compared with that of which we are ignorant. – Plato

Science fiction writers, I am sorry to say, really do not know anything. We cant talk about science, because our knowledge of it is limited and unofficial, and usually our fiction is dreadful. – Philip K. Dick

Opinion is the medium between knowledge and ignorance. – Plato