We see what is the state of the question; the ancient theories, which hitherto seemed to account for all known phenomena, have encountered an unexpected obstacle. It seemed that a modification was necessary. A hypothesis was first presented in Mr. Planck’s mind, but so strange that he was tempting to look for all the means to overcome it; these means have been vainly sought after. And this does not prevent the new theory from raising a lot of difficulties, many of which are real and are not mere illusions due to the laziness of our mind, which is reluctant to change its habits.
It is impossible for the moment to predict what will be the final outcome; will we find another entirely different explanation? Or, on the contrary, will the proponents of the new theory succeed in removing the obstacles which prevent us from adopting without reserve? Will discontinuity reign over the physical universe and is its triumph definitive? Or will it be recognized that this discontinuity is only apparent and conceals a series of continuous processes. The first who saw a collision thought to observe a discontinuous phenomenon, and we know today that he saw only the effect of very fast, but continuous changes of speed. Seeking to give an opinion on these questions today would be a waste of ink.