Yes, EMPIRICISM is a Scrabble word!

Letter values in Scrabble US: E 1, M 3, P 3, I 1, R 1, I 1, C 3, I 1, S 1, M 3.

Is it a valid word?

EMPIRICISM is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(philosophy) the doctrine that knowledge derives from experience
the application of empirical methods in any art or science
medical practice and advice based on observation and experience in ignorance of scientific findings

Also: empiricist philosophy.