The British philosopher Bertrand Russell said that philosophy went downhill after Democritus and did not recover until the Renaissance.
Leon M. LedermanTheorists tend to peak at an early age; the creative juices tend to gush very early and start drying up past the age of fifteen-or so it seems. They need to know just enough; when they're young they haven't accumulated the intellectual baggage.
Leon M. LedermanA theoretical physicist can spend his entire lifetime missing the intellectual challenge of experimental work, experiencing none of the thrills and dangers - the overhead crane with its ten-ton load, the flashing skull and crossbones and danger, radioactivity signs. A theorist's only real hazard is stabbing himself with a pencil while attacking a bug that crawls out of his calculations.
Leon M. Lederman