first proposed by British philosopher John Stuart Mill, mental chemistry with respect to ideas was not simply building on ideas already understood, but instead the formation of entirely new concepts which disagreed and directly opposed his fathers theories on the matter which was modelled on physical chemistry theories.
MENTAL CHEMISTRY: “Mental chemistry, which was first proposed by John Stuart Mill, considered memories and ideas within the brain, and suggested that compound ideas may simply be ‘new’ ideas opposed to a collection of ideas already held as previously proposed.”