Haecceity (; from the Latin haecceitas, which translates as "thisness") is a term from medieval scholastic philosophy, first coined by followers of Duns Scotus to denote a concept that he seems to have originated: the irreducible determination of a thing that makes it this particular thing. Haecceity is a person's or object's thisness, the individualising difference between the concept "a man" and the concept "Socrates" (i.e., a specific person). In modern philosophy of physics, it is sometimes referred to as primitive thisness. Etymology Haecceity is a Latin neologism formed as an abstract noun derived from the demonstrative pronoun "haec(ce)", meaning "this (very)" (feminine singular) or "these (very)" (feminine or neuter plural). It is apparently formed on the model of another (much older) neologism, viz. "qui(d)ditas" ("whatness"), which is a calque of Aristotle's Greek to ti esti (τὸ τί ἐστι) or "the what (it) is." Haecceity vs. quiddity Haecceity may be defined in some dictionaries as simply the "essence" of a thing, or as a simple synonym for quiddity or hypokeimenon. However, in proper philosophical usage these terms have not only distinct but opposite meanings. Whereas haecceity refers to aspects of a thing that make it a particular thing, quiddity refers to the universal qualities of a thing, its "whatness", or the aspects of a thing it may share with other things and by which it may form part of a genus of things. Haecceity in scholasticism Duns Scotus makes the following distinction: In Scotism and the scholastic usage in general, therefore, "haecceity" properly means the irreducible individuating differentia which together with the specific essence (i.e. quiddity) constitutes the individual (or the individual essence), in analogy to the way specific differentia combined with the genus (or generic essence) constitutes the species (or specific essence). Haecceity differs, however, from the specific differentia, by not having any conceptually specifiable content: it does not add any further specification to the whatness of a thing but merely determines it to be a particular unrepeatable instance of the kind specified by the quiddity. This is connected with Aristotle's notion that an individual cannot be defined. Individuals are more perfect than the specific essence and thus have not solely a higher degree of unity, but also a greater degree of truth and goodness. God multiplied individuals to communicate to them His goodness and beatitude. Haecceity in anglophone philosophy In analytical philosophy, the meaning of "haecceity" shifted somewhat.