Every major science, including physics, biology, and chemistry, are disciplines that were once considered as philosophy. Medicine was always considered a practical art, however. As facts about nature became more understood, these subjects branched away. Psychology only split a century and a half ago. In our own time, subjects such as consciousness studies, decision theory, and applied ethics have increasingly found independence from philosophy as a whole. Because of this, philosophy seems useful because it spins off new kinds of science.