Persistence in research often pays off when you least expect it.

The present state of the system of nature is evidently a consequence of what it was in the preceding moment, and if we conceive of an intelligence which at a given instant comprehends all the relations of the entities of this universe, it could state the respective positions, motions, and general effects of all these entities at any time in the past or future.

如果你认为一个理论是唯一可能的理论，这表明你既不理解这个理论，也不理解这个理论要解决的问题。