It is usually considered the more reliable method, although many cases confirm deductive methods by experiment and observation. The deductive method is considered most reliable when scientists observe that a planet orbits around a star. They then try to solve the cosmological problem, i.e., whether or not the planet, which they believe to be orbiting around the star, will continue to move around the star without falling off. If it does pass a theoretical test with this result, it is considered a proven scientific theory.