By reference to nominated attributes, a genus, being a population of objects of one specified kind, may be partitioned into species, being subpopulations of different kinds. A prototype is an object representative of its species within the genus. Using this framework, the paper describes how objects can be relatively differentiated with respect to attributes, and how attributes can be relatively differentiating with respect to objects. Methods and rationale for such differential ordering of objects and attributes are presented by example, formal development, and application.

For a genus Ω comprising n species of object there is a subset P ofn distinct prototypes. With respect to m nominated attributes, each object in Ω has an m-element characterization. Together these determine an n × m objects × attributes matrix, the rows of which are the characterizations of the prototypical objects. Over then species in Ω, an associated relative frequency vector gives the distribution of objects (and of their characterizations). The matrix and vector associate the objects in Ω with points in a metric space (P, δ); and it is with respect to various sums of distances in this attribute space that one can differentially order objects and attributes.

The definition of the distance function δ is generalized across kinds of difference, types of characterization, scale-types of measurement, Minkowski index ≧ 1, and any form of distribution of objects over species. Explanatory and taxonomic applications in psychology and other fields are discussed, with focus on classification, identification, recognition, and search. The Braille code and the identification of its characters provide illustration.

This article positions braille as a writing system worthy of study in its own right and on its own terms. We begin with a discussion of the role of braille in the lives of those who read and write it and a call for more attention to braille in the reading sciences. We then give an overview of the history and development of braille, focusing on its formal characteristics as a writing system, in order to acquaint sighted print readers with the basics of braille and to spark further interest among reading researchers. We then explore how print-centric assumptions and sight-centric motivations have potentially negative consequences, not only for braille users but also for the types of questions researchers think to pursue. We conclude with recommendations for conducting responsible and informed research about braille. We affirm that blindness is most equitably understood as but one of the many diverse ways humans experience the world. Researching braille literacy from an equity and diversity perspective provides positive, fruitful insights into perception and cognition, contributes to the typologically oriented work on the world’s writing systems, and contributes to equity by centering the perspectives and literacy of the people who read and write braille.

This paper explores the social, medical, institutional and enumerative histories of blindness in British India from 1850 to 1950. It begins by tracing the contours and causes of blindness using census records, and then outlines how colonial physicians and observers ascribed both infectious aetiologies and social pathologies to blindness. Blindness was often interpreted as the inevitable consequence of South Asian ignorance, superstition and backwardness. This paper also explores the social worlds of the Blind, with a particular focus on the figure of the blind beggar. This paper further interrogates missionary discourse on ‘Indian’ blindness and outlines how blindness was a metaphor for the perceived civilisational inferiority and religious failings of South Asian peoples. This paper also describes the introduction of institutions for the Blind in addition to the introduction of Braille and Moon technologies.