It has also been suggested (for example, in Jean Piaget's 1918 work Recherche) that the unity of science can be considered in terms of a circle of the sciences, where logic is the foundation for mathematics, which is the foundation for mechanics and physics, and physics is the foundation for chemistry, which is the foundation for biology, which is the foundation for sociology, the moral sciences, psychology, and the theory of knowledge, and the theory of knowledge is based on logic.[1]