"Indeed, throughout the whole of this subject, the selection of the proper theoretical ground of explanation is a matter of judgment. In some cases we may conceive that we are justified in using the Equilibrium theory; in others the Wave-theory will apply, completely or partially... as a last resource, in almost every case, we shall be driven to the same arbitrary suppositions which Laplace introduced. ...In the instances which it does not master completely, it will show that there are ample grounds for the arbitrary alterations of constants introduced by Laplace in his suppositions..."