Some things exist if you believe, but they don't exist if you don't believe. But the profession of Mr. Feng Shui has existed in China for thousands of years, which is not unreasonable. As for the theory of ghosts and gods, from a scientific point of view, there is no such thing, and it is hard to say whether those things around us that cannot be explained scientifically are "ghosts and gods".
Sometimes it's not that Mr. Feng Shui knows everything, but when he says something to answer his questions, your expression and actions will make him guess.