 Goodwin (2012) identifies two notions of chemical mechanism at play in chemistry. The first or thick notion of mechanism is like a motion picture of a chemical reaction. Such a mechanism traces out the positions of all of the electrons and atomic cores of some set of molecules during the course of a reaction, and correlates these positions to the potential energy or free energy of the system. One might think of this as an ideal reaction mechanism, as it would contain all information about the time course of a chemical reaction.