It really comes down to parsimony, economy of explanation. It is possible that your car engine is driven by psychokinetic energy, but if it looks like a petrol engine, smells like a petrol engine and performs exactly as well as a petrol engine, the sensible working hypothesis is that it is a petrol engine.
Richard DawkinsI can remember at the age of about six being fascinated by the planets and learning all about Mars and Venus and things.
Richard DawkinsWe who are atheists are also a-fairyists, a-teapotists, and a-unicornists, but we don't have to bother saying so.
Richard Dawkins