The thought police would get him just the same. He had committed – would have committed, even if he had never set pen to paper – the essential crime that contained all others in itself. Thoughtcrime, they called it. Thoughtcrime was not a thing that could be concealed forever. You might dodge successfully for a while, even for years, but sooner or later they were bound to get you.
– George Orwell
1984. Part 1, Chapter 1. When Winston Smith sets out to challenge the Party’s power, he discovers the real extend of its ability to control and enslave people . In this society thoughts are not free.