There is a popular view that all of the natural sciences can be arranged in a chain or ladder according to the complexity of their subjects.
On this view, physics forms the base of the ladder because it deals with the simplest building-blocks of matter, atoms and subatomic particles. Chemistry is next up because it studies interacting atoms i.e. molecules. Biology studies complex collections of molecules, i.e. cells. Then comes neuroscience which deals with a complex collection of interacting