I believe that with the advent of acid, we discovered a new way to think, and it has to do with piecing together new thoughts in your mind. Why is it that people think it's so evil? What is it about it that scares people so deeply, even the guy that invented it, what is it? Because they're afraid that there's more to reality than they have ever confronted. That there are doors that they're afraid to go in, and they don't want us to go in there either, because if we go in we might learn something that they don't know. And that makes us a little out of their control.

As quoted in the BBC documentary The Beyond Within: The Rise and Fall of LSD (1987)