Problem of universals
The problem of universals is an ancient question from metaphysics that has inspired a range of philosophical topics and disputes: "Should the properties an object has in common with other objects, such as color and shape, be considered to exist beyond those objects? And if a property exists separately from objects, what is the nature of that existence?"[1]
The problem of universals relates to various inquiries closely related to metaphysics, logic, and epistemology, as far back as Plato and Aristotle, in efforts to define the mental connections a human makes when they understand a property such as shape or color to be the same in nonidentical objects.[2]
Universals are qualities or relations found in two or more entities.[3] As an example, if all cup holders are circular in some way, circularity may be considered a universal property of cup holders.[4] Further, if two daughters can be considered female offspring of Frank, the qualities of being female, offspring, and of Frank, are universal properties of the two daughters. Many properties can be universal: being human, red, male or female, liquid or solid, big or small, etc.[5]
Philosophers agree that human beings can talk and think about universals, but disagree on whether universals exist in reality beyond mere thought and speech.
Medieval philosophy[edit]
Boethius[edit]
The problem was introduced to the medieval world by Boethius, by his translation of Porphyry's Isagoge. It begins:
"I shall omit to speak about genera and species, as to whether they subsist (in the nature of things) or in mere conceptions only; whether also if subsistent, they are bodies or incorporeal, and whether they are separate from, or in, sensibles, and subsist about these, for such a treatise is most profound, and requires another more extensive investigation".[14]
Boethius, in his commentaries on the aforementioned translation, says that a universal, if it were to exist, has to apply to several particulars entirely. He also specifies that they apply simultaneously at once and not in a temporal succession. He reasons that they cannot be mind-independent, i.e. they do not have a real existence, because a quality cannot be both one thing and common to many particulars in such a way that it forms part of a particular's substance, as it would then be partaking of universality and particularity. However, he also says that universals can't also be of the mind since a mental construct of a quality is an abstraction and understanding of something outside of the mind. He concludes that either this representation is a true understanding of the quality, in which case we revert to the earlier problem faced by those who believe universals are real; or, if the mental abstractions were not a true understanding, then 'what is understood otherwise than the thing is false'.[2]
His solution to this problem was to state that the mind is able to separate in thought what is not necessarily separable in reality. He cites the human mind's ability to abstract from concrete particulars as an instance of this. This, according to Boethius, avoids the problem of Platonic universals being out there in the real world, but also the problem of them being purely constructs of the mind in that universals are simply the mind thinking of particulars in an abstract, universal way.[2] His assumption focuses on the problems that language create. Boethius maintained that the structure of language corresponds to the structure of things and that language creates what he regarded as philosophical babble of confused and contradictory accounts of the nature of things.[15] To illustrate his view, suppose that although the mind cannot think of 2 or 4 as an odd number, as this would be a false representation, it can think of an even number that is neither 2 nor 4.
Modern and contemporary philosophy[edit]
Hegel[edit]
The 19th-century German philosopher Georg Wilhelm Friedrich Hegel discussed the relation of universals and particulars throughout his works. Hegel posited that both exist in a dialectical relationship to one another; that is, one exists only in relation and in reference to the other.
He stated the following on the issue:
Indian philosophy[edit]
Nyāya-Vaiśeṣika (Realist position)[edit]
Indian philosophers raise the problem of universals in relation to semantics.[27] Universals are postulated as referents for the meanings of general terms.
The Nyāya-Vaiśeṣika school conceives of universals as perceptible eternal entities, existing independently of our minds. Nyāya postulates the existence of universals based on our experience of a common characteristic among particulars. Thus, the meaning of a word is understood as a particular further characterized by a universal.[28] For example, the meaning of the term 'cow' refers to a particular cow characterized by the universal of 'cowness'. Nyāya holds that although universals are apprehended differently from particulars, they are not separate, given their inherence in the particulars.[29]
Not every term, however, corresponds to a universal. Udāyana puts forward six conditions for identifying genuine universals.[30]
Mīmaṃsã (Realist position)[edit]
Like the Nyāya-Vaiśeṣika school, Mīmaṃsã characterizes universals as referents for words. The fundamental difference between Bhāṭṭa Mīmaṃsā's and Nyāya is that Bhāṭṭa Mīmaṃsa rejects the Nyāya understanding of the universals' relation of inherence to the particulars.[29] The Hindu philosopher Kumārila Bhaṭṭa argues that if inherence is different from the terms of the relation, it would continuously require another common relation, and if the inherence is non-different, it would be superfluous.[29]
Buddhist Nominalism[edit]
Buddhist ontology regards the world as consisting of momentary particulars and mentally constructed universals.[31] In contrast to the realist schools of Indian philosophy, Buddhist logicians put forward a positive theory of nominalism, known as the apoha theory, which denies the existence of universals.
The apoha theory identifies particulars through double negation, not requiring for a general shared essence between terms. For instance, the term 'cow' can be understood as referring to every entity of its exclusion class 'non-cow'.[32]