This begins the rise of what Davies regards as "The Anti-Philosophical Agnosticism" in the psychological community, wherein happiness as a concept is warped from being a personal subjective experience to an objective quantifiable phenomenon. This "Anti-Philosophical Agnosticism" is further reflected in the works of economist William Stanley Jevons, behaviorist John Watson, and The Chicago School of Economics. The main problem of quantifying pleasure and happiness is there is no one factor that may be objectively observed, since emotions are by their natures subjective experiences; so, according to Davies, psychologists have used other units to measure happiness such as money, dopamine, and body language.