He has been there and has empirical knowledge of the system.
Advanced English Dictionary
+adjective [usually before noun] based on experiments or experience rather than ideas or THEORIES: empirical evidence / knowledge / research + an empirical study empirically adverb: Such claims need to be tested empirically. + empirically false / true / valid
Random quote: To be fully alive, fully human, and completely awake is to be continually thrown out of the nest.: Pema Chodron