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?"
"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."
"He who controls the past controls the future. He who controls the present controls the past."
"Reality exists in the human mind, and nowhere else."
"The best books... are those that tell you what you know already."