Georg Elias Müller (20 July 1850 – 23 December 1934) “is the first experimental psychologist…who was little else than an experimental psychologist. He brought his philosophical acumen into his work by his logical precision and his trenchant criticism, and, by avoiding philosophy and becoming a scientist, he lived up approximately to the teaching of philosophy of his youth that science must precede philosophizing. Within experimental psychology, he ehibited a broad interest and fertile mind. His students received from him more than their meed of inspiration and help, and through his own work and through theirs he exerted a great influence upon experimental psychology in its formative years.”
Edwin G. Boring, The American Journal of Psychology 47 (2): 344–348.