More quotes by George Orwell, 1984

"For, after all, how do we know that two and two make four? Or that the force of gravity works? Or that the past is unchangeable? If both the past and the external world exist only in the mind, and if the mind itself is controllable – what then?"
"The words kept coming back to him, statement of a mystical truth and a palpable absurdity."
"At present nothing is possible except to extend the area of sanity little by little. We cannot act collectively. We can only spread our knowledge outwards from individual to individual, generation after generation."
"To the future or to the past, to a time when thought is free, when men are different from one another and do not live alone— to a time when truth exists and what is done cannot be undone: From the age of uniformity, from the age of solitude, from the age of Big Brother, from the age of doublethink — greetings!"
"For, after all, how do we know that two and two make four? Or that the force of gravity works? Or that the past is unchangeable? If both the past and the external world exist only in the mind, and if the mind itself is controllable – what then?"