What is useful for mankind is the simple observation of an experimental result which in itself creates a new world from the old. The world is round, not flat. The planets revolve around the Sun, not around the Earth. The benzene ring rationalizes organic chemistry. Gravity is a flow not a force.
Space consists of pure energy, the distortion of which engenders the created world.
All of these observations are the result of the examination of many experiments, the collation of enormous data. If it is said that to read the results of one year's accumulation of experimental data takes 12 years, then the reader has not learned to reject the absurd, to cull out the ineptly taken experimental data, to exercise discrimination between the real and the unreal. The complete scientist is a balanced person. He has the discernment and discrimination to perceive the underlying truths of nature, hidden beneath the multiplicity of experimental appearances. He has enough sense not to extend his theoretical expectations beyond the resolution of his experiments.