Naturalism is the dogmatic belief, based on an assumption, that God, spirits, and angels do nothing.  It is the assumption is that only Natural forces cause things to happen.  This is the belief in a negative, that God does NOT act on our lives and on creation.  This belief in Naturalism is based on a logical error known as a universal negative--in order to know such a thing, one would have to be all-knowing.   It is one of several related cults that work in concert: Agnosticism,   Atheism,   Evolutionism,   Humanism,   Intellectualism,   Liberalism,   Materialism,   Modernism,   Naturalism,   Post Modernism,   Rationalism,   Relativism,  Secularism,  and Socialism/Communism