 Its principles are summed up in a more popular form in d'Holbach's "Bon Sens, ou idées naturelles opposees aux idées surnaturelles".The book was considered extremely radical in its day and the list of people writing refutations of the work was long.The prominent Catholic theologian Nicolas-Sylvestre Bergier wrote a refutation titled "Examen du matérialisme" ("Materialism examined").