It’s true that the physicists of the later 19th Century believed that they had discovered all the major, basic principles that govern the universe.  Then, of course, came Einstein, followed by the quantum physicists and all the theoretical stuff that has come along since.

Science remains thirsty for new discoveries, and we should not expect anyone of any stature in this arena to tell us that they have physics entirely “in the can.”

Physics Is Very Unlikely to Achieve a Complete Understanding of the Universe