Editing William of Ockham (section)

==Philosophical thought==
{{Catholic philosophy}}

In [[scholasticism]], William of Ockham advocated reform in both method and content, the aim of which was simplification. William incorporated much of the work of some previous theologians, especially [[Duns Scotus]]. From Duns Scotus, William of Ockham derived his view of divine omnipotence, his view of grace and justification, much of his epistemology and ethical convictions.<ref>Lucan Freeport, ''Basis of Morality According to William Ockham'', {{ISBN|978-0-8199-0918-3}}, Franciscan Herald Press, 1988.</ref> However, he also reacted to and against Scotus in the areas of predestination, penance, his understanding of universals, his formal distinction {{lang|la|ex parte rei}} (that is, "as applied to created things"), and his view of parsimony which became known as [[Occam's razor]].

===Faith and reason===
William of Ockham espoused [[fideism]], stating that "only faith gives us access to theological truths. The ways of God are not open to reason, for God has freely chosen to create a world and establish a way of salvation within it apart from any necessary laws that human logic or rationality can uncover."<ref>Dale T. Irvin and Scott W. Sunquist. ''History of World Christian Movement'' Volume I: Earliest Christianity to 1453, p. 434. {{ISBN|978-1-57075-396-1}}</ref> He believed that science was a matter of discovery and saw God as the only ontological necessity.<ref name="stanford"/> His importance is as a theologian with a strongly developed interest in logical method, and whose approach was critical rather than system building.<ref name="English Literature p 735">''The Oxford Companion to English Literature'', 6th ed. Edited by [[Margaret Drabble]], Oxford University Press, 2000, p. 735.</ref>

===Nominalism===
William of Ockham was a pioneer of [[nominalism]], and some consider him the father of modern [[epistemology]], because of his strongly argued position that only individuals exist, rather than supra-individual [[universal (metaphysics)|universals]], essences, or forms, and that universals are the products of abstraction from individuals by the human mind and have no extra-mental existence.<ref>{{cite book |last1=Baird |first1=Forrest E. |title=From Plato to Derrida |last2=Kaufmann |first2=Walter |publisher=Pearson Prentice Hall |year=2008 |isbn=978-0-13-158591-1 |location=Upper Saddle River, New Jersey |author-link2=Walter Kaufmann (philosopher)}}</ref> He denied the real existence of metaphysical universals and advocated the reduction of [[ontology]].{{cn|date=September 2024}}

William of Ockham is sometimes considered an advocate of [[conceptualism]] rather than nominalism, for whereas nominalists held that universals were merely names, i.e. words rather than extant realities, conceptualists held that they were mental [[concept]]s, i.e. the names were names of concepts, which do exist, although only in the mind. Therefore, the universal concept has for its object, not a reality existing in the world outside us, but an internal representation which is a product of the understanding itself and which "supposes" in the mind the things to which the mind attributes it; that is, it holds, for the time being, the place of the things which it represents. It is the term of the reflective act of the mind. Hence the universal is not a mere word, as [[Roscellinus|Roscelin]] taught, nor a ''sermo'', as [[Peter Abelard]] held, namely the word as used in the sentence, but the mental substitute for real things, and the term of the reflective process. For this reason William has sometimes also been called a "[[Terminism (Philosophy)|Terminist]]", to distinguish him from a nominalist or a conceptualist.<ref name="Turner1913">{{Catholic Encyclopedia| year=1913|wstitle = William of Ockham | author =William Turner|inline=yes}}</ref>

===Efficient reasoning===
One important contribution that he made to modern science and modern intellectual culture was efficient reasoning with the principle of parsimony in explanation and theory building that came to be known as [[Occam's razor]]. This maxim, as interpreted by [[Bertrand Russell]],<ref name="russell">{{cite book |last=Russell |first=Bertrand |title=[[A History of Western Philosophy]] |publisher=[[Allen & Unwin]] |year=2000 |isbn=0-415-22854-9 |pages=462–463 |author-link=Bertrand Russell}}</ref> states that if one can explain a phenomenon without assuming this or that hypothetical entity, there is no ground for assuming it, i.e. that one should always opt for an explanation in terms of the fewest possible causes, factors, or variables. He turned this into a concern for ontological parsimony; the principle says that one should not multiply entities beyond necessity—{{lang|la|Entia non sunt multiplicanda sine necessitate}}—although this well-known formulation of the principle is not to be found in any of William's extant writings.<ref name="thorburn">{{cite journal |url=https://en.wikisource.org/wiki/The_Myth_of_Occam's_Razor |title=The Myth of Occam's Razor |journal=[[Mind (journal)|Mind]] |first=W. M. |last=Thorburn |volume=27 |issue=107 |pages=345–353 |year=1918 |doi=10.1093/mind/XXVII.3.345 |access-date=15 May 2022}}</ref> He formulates it as: "For nothing ought to be posited without a reason given, unless it is self-evident (literally, known through itself) or known by experience or proved by the authority of Sacred Scripture."<ref>Spade, Paul Vincent (ed.). ''The Cambridge Companion to Ockham''. Cambridge University Press, 1999, p. 104.</ref> For William of Ockham, the only truly necessary entity is God; everything else is contingent. He thus does not accept the [[principle of sufficient reason]], rejects the distinction between essence and existence, and opposes the [[Thomism|Thomistic doctrine]] of active and passive intellect. His scepticism to which his ontological parsimony request leads appears in his doctrine that human reason can prove neither the immortality of the soul; nor the existence, unity, and infinity of God. These truths, he teaches, are known to us by revelation alone.<ref name="Turner1913"/>

===Natural philosophy===
William wrote a great deal on [[natural philosophy]], including a long commentary on Aristotle's [[Physics (Aristotle)|''Physics'']].<ref>André Goddu, ''The Physics of William of Ockham'',  {{ISBN|978-90-04-06912-1}}, Brill Academic Pub., 1984.</ref> According to the principle of ontological parsimony, he holds that we do not need to allow entities in all ten of Aristotle's categories; we thus do not need the category of quantity, as the mathematical entities are not "real". Mathematics must be applied to other categories, such as the categories of substance or qualities, thus anticipating modern scientific renaissance while violating Aristotelian prohibition of ''metabasis''.

===Theory of knowledge===
In the theory of knowledge, William rejected the scholastic theory of species, as unnecessary and not supported by experience, in favour of a theory of abstraction. This was an important development in late medieval [[epistemology]]. He also distinguished between intuitive and abstract cognition; intuitive cognition depends on the existence or non-existence of the object, whereas abstractive cognition "abstracts" the object from the existence predicate. Interpreters are, as yet, undecided about the roles of these two types of cognitive activities.<ref>{{cite journal |last1=Brower-Toland |first1=S |title=William ockham on the scope and limits of consciousness |journal=Vivarium |date=2014 |volume=52 |issue=3–4 |pages=197–219 |doi=10.1163/15685349-12341275 |url=https://philpapers.org/rec/BROQOO}}</ref>

===Political theory===
William of Ockham is also increasingly being recognized as an important contributor to the development of Western constitutional ideas, especially those of government with limited responsibility.<ref name="SEP">[https://plato.stanford.edu/entries/ockham/#8 "William of Ockham"]. ''Stanford Encyclopedia of Philosophy''.</ref> He was one of the first medieval authors to advocate a form of church/state separation,<ref name="SEP"/> and was important for the early development of the notion of property rights. His political ideas are regarded as "natural" or "secular", holding for a secular absolutism.<ref name="SEP"/> The views on monarchical accountability espoused in his ''Dialogus'' (written between 1332 and 1347)<ref>{{cite web |url=http://www.britac.ac.uk/pubs/dialogus/ockdial.html |publisher=British Academy |title=William of Ockham: Dialogus}}</ref> greatly influenced the [[Conciliarism|Conciliar movement]].<ref>{{cite book |last1=Tierney |first1=Brian |title=Foundations of the conciliar theory: the contribution of the medieval canonists from Gratian to the Great Schism |date=1998 |publisher=Brill |location=Leiden |isbn=978-90-04-10924-7 |edition=Enlarged |author-link=Brian Tierney (medievalist)}}</ref> This tract on heresy had the ultimate purpose to establish the possibility of papal heresy and to consider what action should be taken against a pope who had become a heretic.<ref>{{cite web |url=https://publications.thebritishacademy.ac.uk/pubs/dialogus/frmIntro1d1.html|first=John |last=Scott|title=Theologians vs Canonists on Heresy|archive-url=https://archive.today/20250324113310/https://publications.thebritishacademy.ac.uk/pubs/dialogus/frmIntro1d1.html|website=[[British Academy]] |archive-date=March 24, 2025 |url-status=live}} </ref>

William argued for complete separation of spiritual rule and earthly rule.<ref>Takashi Shogimen, ''Ockham and Political Discourse in the Late Middle Ages''. {{ISBN|978-0-521-84581-6}}, Cambridge University Press, 2007.</ref> He thought that the pope and churchmen have no right or grounds at all for secular rule like having property, citing 2 Timothy 2:4. That belongs solely to earthly rulers, who may also accuse the pope of crimes, if need be.<ref name=vm>Virpi Mäkinen, ''Keskiajan aatehistoria'', Atena Kustannus Oy, Jyväskylä, 2003, {{ISBN|978-951-796-310-7}}. pp. 160, 167–168, 202, 204, 207–209.</ref>

After the [[Fall of man|Fall]] he believed God had given humanity, including non-Christians, two powers: private ownership and the right to set their rulers, who should serve the interest of the people, not some special interests. Thus he preceded [[Thomas Hobbes]] in formulating [[social contract]] theory along with earlier scholars.<ref name=vm/>

William of Ockham said that the Franciscans avoided both private and common ownership by using commodities, including food and clothes, without any rights, with mere {{lang|la|usus facti}}, the ownership still belonging to the donor of the item or to the pope. Their opponents such as [[Pope John XXII]] wrote that use without any ownership cannot be justified: "It is impossible that an external deed could be just if the person has no right to do it."<ref name=vm/>

Thus the disputes on the heresy of Franciscans led William of Ockham and others to formulate some fundamentals of economic theory and the theory of ownership.<ref name=vm/>

According to John Kilcullen, "Ockham's Utilitarian theory of property, his defence of civil and (within limits) religious liberty, and his emphasis on the inevitability of exceptions to rules and the need to adapt institutions to changing circumstances, anticipate [[John Stuart Mill|J.S. Mill]]" (via Aristotle).<ref>{{cite web|first=John|last=Kilcullen|title=Ockham's Political Writings|publisher=Cambridge University Press|year=1999|url=https://publications.thebritishacademy.ac.uk/pubs/dialogus/polth.html|access-date=March 24, 2025|archive-date=24 March 2025|archive-url=https://archive.today/20250324115229/https://publications.thebritishacademy.ac.uk/pubs/dialogus/polth.html|url-status=bot: unknown}}</ref>

===Logic===
In [[logic]], William of Ockham wrote down in words the formulae that would later be called [[De Morgan's laws]],<ref>In his ''Summa Logicae'', part II, sections 32 and 33.Translated on p. 80 of ''Philosophical Writings'', tr. [[Philotheus Boehner|P. Boehner]], rev. S. Brown, (Indianapolis, Indiana, 1990)</ref> and he pondered [[three-valued logic|ternary logic]], that is, a [[logical system]] with three [[truth values]]; a concept that would be taken up again in the [[mathematical logic]] of the 19th and 20th centuries. His contributions to [[semantics]], especially to the maturing [[theory of supposition]], are still studied by logicians.<ref>{{cite journal |first1=Graham |last1=Priest |author-link1=Graham Priest |last2=Read |first2=S. |title=The Formalization of Ockham's Theory of Supposition |journal=Mind |volume=LXXXVI |pages=109–113 |year=1977 |doi=10.1093/mind/LXXXVI.341.109 |issue=341}}</ref><ref>{{cite journal |author-link1=John Corcoran (logician) |first1=John |last1=Corcoran |first2=John |last2=Swiniarski |year=1978 |title=Logical Structures of Ockham's Theory of Supposition |journal=Franciscan Studies |volume=38 |pages=161–183 |jstor=41975391 |doi=10.1353/frc.1978.0010 |s2cid=170450442}}</ref> William of Ockham was probably the first logician to treat empty terms in Aristotelian syllogistic effectively; he devised an empty term semantics that exactly fit the syllogistic. Specifically, an argument is valid according to William's semantics if and only if it is valid according to ''Prior Analytics''.<ref>John Corcoran (1981). "Ockham's Syllogistic Semantics", ''Journal of Symbolic Logic'', '''46''': 197–198.</ref>

=== Philosophy of Time ===
William of Ockham believed that [[eternity]] was exclusive to God.<ref name="Steel2001">{{Cite journal |last=Steel |first=Carlos |date=2001-06-21 |editor-last=Porro |editor-first=Pasquale |title=The Neoplatonic Doctrine of Time and Eternity and its Influence on Medieval Philosophy |url=https://brill.com/display/book/edcoll/9789004453197/B9789004453197_s003.xml |journal=The Medieval Concept of Time |pages=3–31 |doi=10.1163/9789004453197_003 |isbn=978-90-04-45319-7}}</ref> He rejected the concept of the [[aevum]] as a special measure of duration of for angels.<ref name="Steel2001" /> He also said it is not proper to call eternity a measure of duration.<ref name="Steel2001" /> In William's view, there was only one measure of duration, time, which was shared by all creation.<ref name="Steel2001" />