Editing Problem of universals (section)

==Medieval philosophy==

=== Boethius ===
The problem was introduced to the medieval world by [[Boethius]] (c. 480–524 AD), by his translation of [[Porphyry (philosopher)|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".<ref>{{cite web|url=http://www.tertullian.org/fathers/porphyry_isagogue_02_translation.htm|title=Porphyry, Introduction (or Isagoge) to the logical Categories of Aristotle (1853) vol. 2. pp.609-633.|last=Porphyry|website=www.tertullian.org}}</ref>

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 (philosophy)|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'.<ref name="Stanford Universals" />

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.<ref name="Stanford Universals" /> 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.<ref>{{Cite book|last=Sweeney|first=Eileen|title=Logic, Theology and Poetry in Boethius, Anselm, Abelard, and Alan of Lille: Words in the Absence of Things|publisher=Palgrave Macmillan|year=2016|isbn=978-1-349-73540-2|location=New York|pages=9–10}}</ref> 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.{{huh|date=March 2025}}{{or|date=March 2025}}

===Medieval realism===
{{main|Medieval realism}}
Boethius mostly stayed close to Aristotle in his thinking about universals. Realism's biggest proponents in the Middle Ages, however, came to be [[Thomas Aquinas]] and [[Duns Scotus]]. Aquinas argued that both the essence of a thing and its existence were clearly distinct;<ref>On Being and Essence, Ch I.</ref> in this regard he is also Aristotelian.

Duns Scotus argues that in a thing there is no real distinction between the essence and the existence; instead, there is only a [[formal distinction]].<ref>Opus Oxoniense I iii 1-2</ref> Scotus believed that universals exist only inside the things that they exemplify, and that they "contract" with the [[haecceity]] of the thing to create the individual. As a result of his realist position, he argued strongly against both nominalism and conceptualism, arguing instead for [[Scotist realism]], a medieval response to the [[conceptualism]] of [[Peter Abelard|Abelard]]. That is to say, Scotus believed that such properties as 'redness' and 'roundness' exist in reality and are mind-independent entities.

Furthermore, Duns Scotus wrote about this problem in his own commentary (''Quaestiones'') on Porphyry's ''Isagoge'', as Boethius had done. Scotus was interested in how the mind forms universals, and he believed this to be 'caused by the intellect'.<ref>{{cite book |last1=Scotus |first1=Duns |title=Quaestiones in librum Porphyrii Isagoge |pages=q. 4 proemium}}</ref> This intellect acts on the basis that the nature of, say, 'humanity' that is found in other humans and also that the quality is attributable to other individual humans.<ref>{{cite book |last=Noone |first=Timothy B. |editor-last=Williams |editor-first=Thomas |title=The Cambridge Companion to Duns Scotus |url=https://archive.org/details/cambridgecompani00will |url-access=limited |publisher=Cambridge University Press|date=2003 |pages=[https://archive.org/details/cambridgecompani00will/page/n117 100]–129 |chapter=Universals and Individuation |isbn=978-0-521-63563-9}}</ref>

===Medieval nominalism===
{{main|Medieval nominalism}}
[[File:William_of_Ockham.png|thumb|150px|William of Ockham]]
The opposing view to realism is one called nominalism, which at its strongest maintains that universals are verbal constructs and that they do not inhere in objects or pre-exist them. Therefore, universals in this view are something which are peculiar to [[cognition|human cognition]] and language. The French philosopher and [[Theology|theologian]] [[Roscellinus]] (1050–1125) was an early, prominent proponent of this view. His particular view was that universals are little more than vocal utterances (''voces'').<ref>{{cite book |last1=Salisbury |first1=John of |editor1-last=Webb |editor1-first=Clemens C.I. |title=Metalogicon 2.17 |date=1929 |publisher=Oxford |page=92}}</ref>

[[William of Ockham]] (1285–1347) wrote extensively on this topic. He argued strongly that universals are a product of abstract human thought. According to Ockham, universals are just words or concepts (at best) that only exist in the mind and have no real place in the external world.<ref>{{cite encyclopedia|last1=Panaccio|first1=Claude|last2=Spade|first2=Paul Vincent|article=William of Ockham|date=2015|article-url=https://plato.stanford.edu/archives/win2016/entries/ockham/|encyclopedia=The Stanford Encyclopedia of Philosophy|editor-last=Zalta|editor-first=Edward N.|edition=Winter 2016|publisher=Metaphysics Research Lab, Stanford University|access-date=2019-02-26}}</ref> His opposition to universals was not based on his [[Ockham's razor|eponymous Razor]], but rather he found that regarding them as real was contradictory in some sense. An early work has Ockham stating that 'no thing outside the soul is universal, either through itself or through anything real or rational added on, no matter how it is considered or understood'. Nevertheless, his position did shift away from an outright opposition to accommodating them in his later works such as the ''Summae Logicae'' (albeit in a modified way that would not classify him as a complete realist).