Lawrence Fishburn once said "What is real? How do you define real? If real is what you can feel, smell, taste and see, then 'real' is simply electrical signals interpreted by your brain".
Okay, so he didn't come up with the line... but it still counts. Our reality is subjective, defined by our own concepts and imagination. That's why I find so much of science so interesting, because real life can sometimes be more fantastic than any fiction we could devise with our limited imaginations.
We'd be liars to say that we understand everything about the universe, or even about ourselves. We don't even know the nature of consciousness.