Final answer:
Realist ontologists assert that the identity of properties across objects of the same class is based on their essential traits. They use various methods like observation for empirical properties and reasoned argumentation for abstract properties, considering philosophical frameworks such as those of Plato and Aristotle, as well as distinctions made by Locke.
Step-by-step explanation:
Realist Ontologists and Property Identity-
For realist ontologists, the identity of particular properties among objects of the same class or species is constituted by the properties' ability to persist across different instances despite particular differences. These ontologists could establish if two properties are of the same sort by examining whether the properties are essential to the nature of the objects in question or whether they are accidental and varying from one individual object to another.
The philosophical basis for determining if properties belong to the same category can vary. For empirical properties, one might employ methods of observation and comparison of physical traits. For example, one could conclude that the properties of two different dogs are the same when considering the species-specific trait of having fur, notwithstanding variations in color or length. In contrast, abstract properties, such as moral values, might be examined through reasoned argumentation or a consensus on definitions within a given community.
Certain philosophical approaches like Plato's theory of forms suggest the existence of an ideal 'form' that embodies the essence of a property across various instances. Aristotle's approach was somewhat different, emphasizing the natural observation of particulars and using the categories of species and genera. For instance, recognizing the concept of 'good' in various contexts may involve seeing how it is employed in specific situations as opposed to attributing it to an ideal form.
John Locke highlighted an important distinction between primary and secondary qualities, where primary qualities reside in the object itself and secondary qualities exist within the perception of the observer. This distinction further complicates the establishment of property identity, as perceptions of qualities such as 'smoothness' or temperature ('hot' and 'cold') are subjective and can vary among individuals.