Greetings from New Jersey, USA (where in fact Einstein taught!). You are onto the point: this is a comic or funny comment from Mulder. It is a bit of sarcasm, as if anyone could best Einstein, instead of simply trying to learn what he taught. It is a gentle put-down, "You think you can advance physics more than Einstein." Notice how quickly Mulder gets past his point in order to permit further discussion with Scully.