The use that the scientist makes of his principles is well known. In the normal course of scientific investigation, a hypothesis which explains some physical phenomenon adequately in every particular, but which runs counter to, say, the laws of inertia, cannot be held without further experimentation. Such experimentation must continue until the irreconcilability of the hypothesis with the laws is resolved. In most cases the hypothesis will fail to submit to further tests, will be declared inadequate, and will give way to a new one.