Reality: How do I ensure that I am not currently in a coma? Here's one trick. Find a piece of text written in a foreign language that you do not understand. It can be anything as long as you are able to memorise a sentence or two. Now go and do something else for ten minutes. After that, go back to the text and look at it again. If it is the same, you're not dreaming. Because your dreams can only ever be constructed out of something your brain already knows.