A.Naturalism evolved from Realism and is an extreme form of realism. It is no more than a different philosophical approach to reality or human existence; B.Realism concerned with what is absorbed by the senses. Naturalism used scientific theories to art; C.Naturalism believes that human subject to heredity and environment and the real and true always beyond control; D.The tone of Naturalistic writings is more ironic and pessimistic and less sympathetic and serious than realistic writings.