On making a difference: towards a minimally non-trivial version of the identity of indiscernibles

The identity of indiscernibles (PII) states that indiscernible objects must be identical. Many philosophers have held that the PII turns out to be either true but trivial, or non-trivial but false, depending on how the notion of (in)discernibility is spelled out. In this paper, I propose and defend an account of this notion which aims to yield a minimally non-trivial and yet plausible version of the PII. I argue moreover that this version of the principle is immune to a number of well-known and recent objections to the PII.

Haecceity and thisness

A ‘haecceity’ (from the Latin, haecceitas, which translates literally as ‘thisness’) is a certain kind of property. In broad outline, a thisness is a primitive, particular, nonqualitative property of an individual, i.e. the property of being a specific individual (or, perhaps, the property of being identical with a specific individual). For example, Ruth Barcan Marcus’s thisness is the property being (identical with) Ruth Barcan Marcus, and so on for all individuals. To clarify: although it is typical to see a thisness described as the property of being identical with an individual, it is not merely the property of being self-identical, which all individuals exemplify trivially; it is a special kind of property that is uniquely exemplified by its bearer. And so, for any individual x, since the property being (identical with) x is both uniquely exemplified by x and essential to x, so x’s thisness is a nonqualitative individual essence of x. The terminology of ‘haecceity’ and ‘thisness’ derives from the work of John Duns Scotus (c.1266–1308) and some of Scotus’s insights and application of thisnesses are still relevant to debates about identity and individuation. This terminology has its roots in the scholastic philosophy of the High Middle Ages and it was revived in contemporary metaphysics by the work of Robert Merrihew Adams in the second half of the 20th century. In addition to the question of what is the metaphysical nature of a thisness, a considerable amount of the debate concerns what thisnesses can do to ‘earn their keep’ in a systematic metaphysics. Some say that accepting an ontology of thisness permits the individuation of qualitatively indiscernible objects or events – with appropriate footnotes to Scotus. Others say that accepting a specific ontology of thisness allows one to defend certain positions in the philosophy of time, i.e. the growing block theory of time, or presentism. We are concerned here with haecceities (thisnesses) and not ‘haecceitism’, the view that a world could not be nonqualitatively different without a qualitative difference.

Rough Set Extension under Incomplete Information System with “?” Values

Classical rough set theory (RST) can't process incomplete information system (IIS) because it is based on an indiscernibility relation which is a kind of equivalent relation. In the literature a non-symmetric similarity relation based rough set model (NS-RSM) has been introduced as an extended model under IIS with ``?" values directly. Unfortunately, in this model objects in the same similarity class are not necessarily similar to each other and may belong to different target classes. In this paper, a new inequivalent relation called Maximal Limited Consistent block relation (MLC) is proposed. The proposed MLC relation improves the lower approximation accuracy by finding the maximal limited blocks of indiscernible objects in IIS with ``?" values. Maximal Limited Similarity rough set model (MLS) is introduced as an integration between our proposed relation (MLC) and NS-RSM. The resulted MLS model works efficiently under IIS with ``?" values. Finally, an illustrative example is given to validate MLS model. Furthermore, approximation accuracy comparisons have been conducted among NS-RSM and MLS. The results of this work demonstrate that the MLS model outperform NS-RSM.

From common object to memory-object: the indiscernibility of Rapa Nui's historical archaeological heritage

In this article I propose the indiscernible objects experiment of Arthur Danto as analogy to discuss on the nature of the industrial archaeological remains. The interdisciplinary research conducted at the Fundo Vaitea, in Rapa Nui (Eastern Island), is presented as an excellent example for the kind of analysis that I propose here. Conceptually considering archaeological remains of this site as material culture theoretically similar to works of art, I discussed issues concerning the distinction, interpretation and transformation of common objects in archaeological vestiges, proposing to understand these as memory-objects. From this aesthetic dimension I propose another standpoint of the problem associated with the study and heritage policies of the recent past materiality, taking as well into account social practices and the particularities of archaeological time involved in this process.