The Philosophical Assumptions and Consequences of Sortal Identity

Abstract

The paper intends to examine some philosophical assumptions and consequences of the so-called sortal identity. The topic of sortals earned the attention of philosophers in the 1960s, especially in connection with P. Geach's book Reference and Generality. The topics of identity, its possible dependence on certain predicates and especially the question of identity criteria subsequently became the subject of an intense philosophical debate. In this context, different concepts of sortals will be outlined. The philosophical significance of sortals lies primarily in the question of individuation and (re)identification of objects. Among sortal theorists, a debate has erupted as to whether some sortals are necessarily connected with individuals, i.e. if it is true that if an individual falls under one sortal, then it cannot fall under another. The positive answer is based on classical Aristotelian essentialism, the negative answer is defended by anti-essentialists. In addition, a hierarchy of sortals is often built in sortal logic, where sortals can (or must) be in the relationship of subordination to another sortal and it is even possible to consider the possibility of the highest sortal as a sortal that is no longer subordinate to any other. Here a direct connection with the Aristotelian hierarchy of categories is offered. Analogies with this doctrine will be the subject of a final comparison.

Keywords

• sortal logic
• logic
• sortals