Definitions
From Program on Ontologies of Neural Structures
November 2009
Contents |
Concept
A concept is something that is created by the human mind, but is not the reflect of an object, or an ensemble of objects existing in the physical world. The notion of neuron is a concept. The image of a particular neuron formed in my mind when I look in the microscope is not a concept. This image is effectively created by the human mind, but it can be mapped to a physical object.
Universal
A universal is a conceptual entity defined by its properties. It does not exist in the physical world, and is not bound in time and space. A cell that displays spiking depolarisations is a universal. As far as I understood, NRTF aims at recognising universals.
Particular (sometimes called individual)
A particular is a physical object, bound in time and space. A particular cell of my brain that is able to display spiking depolarisations is a particular.
Set
A set is an ensemble of particulars. The ensemble of all my neurons is a set. The ensemble of all the particulars that displayed the properties of the universal neuron, in the whole universe and since the beginning of time is also a set. But it is different from the universal neuron.
Class
(Computer science / ontology approach) A class is used to describe a universal. As such, it contains attributes or properties, that correspond to the properties defining the universal. In order to distinguish the different "types" of neurons (see below for "type"), the NRTF will design classes.
Instance
An instance is a physical realisation of a class. In practise, it is indistinguishable from a particular.
Type
A type has two very different definitions. Sense 1: In phylosophy, a type is a category of object. It is an implicit *universal* corresponding to a set (by that, I mean we do not even need to list the properties). Sense 2: In organismic taxonomy, the type is a specific *particular* that define the taxon. Somewhere, in a museum, there is a skeleton labelled type XXX, that define the species Homo sapiens. And when a new skeleton is found, it is compared to the existing types.
