Most of the philosophes considered religion to be a social phenomenon, born from faith, not from reason. They often attacked religious institutions, and the idea that concepts should be accepted without question. Montesquieu once asked, "Is it possible for those who understand nature and have a reasonable idea of God to believe that matter and created things are only 6,000 years old?" Even so, most believed in some concept of God, Diderot being the exception. They did often criticize the way humans practiced their religion. Voltaire once commented that in the beginning, God made man in his own image; but since that time, man had attempted to return the complement.