You believe only what your senses tell you to believe? Do you think that your senses are of any use without its substratum—the consciousness?
When you are not dreaming or hallucinating, your senses together with an un-deluded understanding of plain common sense will distinguish what is real from fantasyland and science fiction. Or you can just put things to a test with a big old sledgehammer. --You can believe what you like though but proof and self delusion should not be confused.