theorist

Etymology

theory + -ist

noun

1. Someone who constructs theories, especially in the arts or sciences.
   Some of the most beautiful and thus appealing physical theories, including quantum electrodynamics and quantum gravity, have been dogged for decades by infinities that erupt when theorists try to prod their calculations into new domains. 2012-01, Michael Riordan, “Tackling Infinity”, in American Scientist, volume 100, number 1, archived from the original on 2013-04-30, page 86