An intriguing paradox concerning dreams and the nature of reality was described by the British writer Eric Bond Hutton in 1989.
As a child Hutton often had lucid dreams in which people and things seemed as solid and real as in waking life. This led him to wonder whether life itself was a dream, even whether he existed only in somebody else's dream.
Once in a while he would have a pre-lucid dream (in which one suspects that one is dreaming).
He always found these somewhat disturbing, but one day hit upon a magic formula to be used in them: "If I find myself asking 'Am I dreaming?' it proves that I am, since this question would never occur to me in waking life."
Yet, such is the nature of dreams, he could never recall it when he needed to.
Many years later, when he came to write about his childhood fascination with dreams, he was struck by a contradiction in his earlier reasoning.
True, asking oneself "Am I dreaming?" in a dream would seem to prove that one is.
And yet that is precisely what he had often asked himself in waking life.
Therein lay a paradox.
What was he to conclude?
That it does not prove one is dreaming, or that life really is a dream?