It appeared in literature and other art forms before19th century. In the middle and late period of19th century, the Enlightenment was regarded as a sign of conformism and was used by literary critics to criticize the works of writers such as alexander pope, edgar allan poe and hermann hesse.
Three basic psychological cognitive components of enlightenment thinkers;
1, the whole universe is completely understandable, and it is dominated by nature rather than supernatural forces.
2. Strict application of "scientific method" can solve the basic problems in all research fields.
3. Human beings get almost endless promotion through "enlightenment". (basically from John Locke's psychology. )