problem of universals

The problem of universals refers to a set of problems that arise when people think about the nature and status of the properties or qualities of objects. Universals are best understood in contrast to individuals. An individual is an object, like a car or a rose. Universals are properties of objects, which, if they exist, can exist in more than one place at the same time. If the car and the rose are both yellow, then they both exhibit the same universal quality of yellowness. Moreover, the mere fact that we can call something a 'car' or a 'rose' suggests that it has a property of 'carness' or 'roseness'. The problem of universals arises when people start to consider in what sense it is possible for a property to exist in more than one place at the same time. It seems clear that there are yellow things, but is there an existing property of 'yellowness'? And if there is such a thing as 'yellowness', what kind of thing is it, and how do we think of yellowness in one object as compared to yellowness in another? The problem of universals is studied by philosophers working in the fields of philosophy of language, cognitive psychology, epistemology, and ontology.
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