Originally Posted By: redewenur

Like Newton's Principia?...but:
But mathematical theory so often necessarily precedes observation. Examples: General Relativity and Quantum Theory. Such discoveries would otherwise be impossible.

That, I think is the main difference between Newton's principia and GR/QM. In the case of Newton, mathematics followed observation; but in the case of GR/QM, observation follows mathematics. I think the acceleration in the filed of theoretical physics has been increasing till GR/QM, and with GR/QM it was expected that within a short period, everything would have been resolved. But after that the acceleration appears to be zero. So I suspect GR and QM are responsible for the stagnation.