Almost since their inception, the natural sciences, those fields that use the scientific method to study nature, have been divided into two branches: the biological sciences and the physical sciences. In part, this division can be viewed as a convenient social contrivance. However, over time it has also served more functional purposes. Physical scientists, when seeking the fundamental laws, have found it necessary to focus on the simplest of systems—elementary particles, atoms, and molecules—items clearly not alive. It also has been convenient for biological scientists to investigate the immense diversity of living things and their elaborate inner workings without simultaneously accepting the burden of trying to follow these complexities.