Blind Acceptance

Rambam (Mishneh Torah, Hilchos Avodah Zara, Perek 2, Halacha 3) writes that it is Biblically prohibited to ask whether the fundamental principles of Judaism are true or not.  Does that mean that anyone who leads a kiruv seminar or attempts to ascertain the validity of his tradition is in violation of a Biblical prohibition?  How can we be obligated to base our lives on principles that we are not allowed to verify?