Winston shrank back upon the bed. Whatever he said, the swift answer crushed him like a bludgeon. And yet he knew, he knew, that he was in the right. The belief that nothing exists outside your own mind – surely there must be some way of demonstrating that it was false? Had it not been exposed long ago as a fallacy? There was even a name for it, which he had forgotten. A faint smile twitched the corners of O'Brien's mouth as he looked down at him.
"I told you, Winston," he said, "that metaphysics is not your strong point. The word you are trying to think of is solipsism. But you are mistaken. This is not solipsism." (3.3.31-32, O’Brien)
If the Party could thrust its hand into the past and say of this or that event, it never happened – that, surely, was more terrifying than mere torture and death? (1.3.17)
The Party told you to reject the evidence of your eyes and ears. It was their final, most essential command. His heart sank as he thought of the enormous power arrayed against him, the ease with which any Party intellectual would overthrow him in debate, the subtle arguments which he would not be able to understand, much less answer. And yet he was in the right! They were wrong and he was right. The obvious, the silly, and the true had got to be defended. Truisms are true, hold on to that! The solid world exists, its laws do not change. Stones are hard, water is wet, objects unsupported fall towards the earth's centre. With the feeling that he was speaking to O'Brien, and also that he was setting forth an important axiom […] (1.7.29-30)