 The historical literature on LOTH suggests an alternative semantically permeated view: Mentalese words are individuated partly through their denotations. The Mentalese word cat is not a piece of formal syntax subject to reinterpretation. It could not have denoted another species, or the number 27, or anything else. It denotes cats by its inherent nature. From a semantically permeated viewpoint, a Mentalese word has its denotation essentially. Thus, there is a profound difference between natural language and mental language. Mental words, unlike natural language words, bring with them one fixed semantic interpretation. The semantically permeated approach is present in Ockham, among other medieval LOT theorists (Normore 2003, 2009). In light of the problems facing neural and functional individuation, Aydede (2005) recommends that we consider taking semantics into account when individuating Mentalese expressions. Rescorla (2012b) concurs, defending a semantically permeated approach as applied to at least some mental representations. He proposes that certain mental computations operate over mental symbols with essential semantic properties, and he argues that the proposal fits well with many sectors of cognitive  science.[10]