Progressive or “great man” history largely credits influential individuals with overall success and expansion of new ideas. One can explain history by the impact of notable people on the world and its progression. Whether by nature or environment some people are simply smarter than others, and these are the individuals who fuel “history”. Progressive history is a straightforward and very surface-level explanation as to why things change. Unlike progressive history, paradigm shift history explains that revolutions are responsible for the change in history. Kuhn thought that there was a set of rules that governed the scientific process, however, sometimes these rules can change. By slowly abandoning the “old” ways, new ideas are formed, and there is a paradigm shift for the scientific community as a whole, most times resulting in a revolution. Paradigm shift history relies on the gradual intellectual advancement of a scientific community to explain historical change. Johnson mentions both the Renaissance and the Enlightenment periods as examples of paradigm shifts in the history of science. A force, both bigger and smaller than a single human is responsible for the spread of this progression. The ecosystem theory is a combination of subjects that are all intertwined together. This connection gives a deeper explanation as to why science excels. Rather than crediting the individual or just simple intellect, the ecosystem theory states that a variety of disciplines build off of each other for advancement and change.
In The Invention of Air, Johnson uses a bit of all three of the models of history, however, he emphasizes the importance of the ecosystem theory to retell Priestley’s oxygen discovery. Johnson tells how Priestley would share his work and findings with others, as well as build off of other scientists when conducting his experiments, therefore also using the ecosystem to tell his story. For example, in the novel, Johnson describes how “Priestley’s whole model of progress was built on the premise that ideas had to move, to circulate, for them to turn into better ideas” (70). Benjamin Franklin’s notes largely supplied Priestley with the needed elements to complete his experiments. Priestley’s engagement in “coffeehouse culture” (the modern version being the internet), which goes hand-in-hand with the ecosystem theory, demonstrates how his success was possible.