  The traditional idea that art is a special vehicle for the expression of important truths is the basis for the work of the philosopher who established the framework for German thought for much of the 18th century, namely, Christian Wolff (1679–1754). Wolff never devoted a whole work to aesthetics, but many of the ideas that would influence subsequent aesthetic theory are contained in his Rational Thoughts on God, the World, and the Soul of Man, his “German Metaphysics,” first published in 1719.