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1. exist as thoughts or concepts formed by the knowing mind. They are mental representations or ideas, conceptualized out of the particular things to which they apply. Their main function is to serve as principles of classification. (p.128, 'Conceptualism', in The Blackwell Dictionary of Western Philosophy)
  • common names (p.128)
  • names rather than entities in their own right (p.474 'nominalism').
  • are terms invented by the mind to talk about similarities (p.475)
  • Something is universal if it pertains to all members of a class or is unlimited, such as a universal law. [...] A universal expresses abstract features, such as justice, beauty, wisdom, and goodness (p.714 'universal')
2. Entities that can have instances. (WonderWeb Deliverable D18)
3. [BFO2.0] A mind-independent, repeatable feature of reality that exists only as instantiated in a respective particular (individual thing, instance) and is also dependent upon a particular for its existence. For example, the two universals red and ball are instantiated in a red ball lying on the floor. All particulars stand in the instantiation relation to some universal. Universals are the sorts of entities that are represented by general terms used in the formulation of scientific laws ([ Arp et al., 2015 ]).


  • Realism claims that universals are mind-independent objective entities, which can in principle be exemplified or instantiated by a number of different things. On the basis of this objective entity, predicateexpressions can be applied to many subjects. (p.714, The Blackwell Dictionary of Western Philosophy)