All processes in organisms obey physical laws, but some argue that the difference between inanimate and biological processes is that the organisation of biological properties is subject to control by coded information. This has led some biologists and philosophers (for example, Ernst Mayr and David Hull) to return to the strictly philosophical reflections of Charles Darwin to resolve some of the problems which confronted them when they tried to employ a philosophy of science derived from classical physics. The positivist approach used in physics emphasised a strict determinism (as opposed to high probability) and led to the discovery of universally applicable laws, testable in the course of experiment. It was difficult for biology, beyond a basic microbiological level, to use this approach. Standard philosophy of science seemed to leave out a lot of what characterised living organisms - namely, a historical component in the form of an inherited genotype.