Editing Early Islamic philosophy (section)

==Metaphysics==
{{Main|Islamic metaphysics}}

===Cosmological and ontological arguments===
{{main|Proof of the Truthful}}
[[Avicenna]]'s proof for the [[existence of God]], known as the "[[Proof of the Truthful]]", was the first [[ontological argument]], which he proposed in the ''Metaphysics'' section of ''[[The Book of Healing]]''.<ref name=Johnson>Steve A. Johnson (1984), "Ibn Sina's Fourth Ontological Argument for God's Existence", ''The Muslim World'' '''74''' (3-4), 161–171.</ref><ref name=Morewedge>{{citation|last=Morewedge|first=P.|title=Ibn Sina (Avicenna) and Malcolm and the Ontological Argument|journal=Monist|year=1970|volume=54|issue=2|pages=234–49|doi=10.5840/monist197054212}}</ref> This was the first attempt at using the method of [[a priori (philosophy)|a priori proof]], which utilizes intuition and reason alone. Avicenna's proof of God's existence is unique in that it can be classified as both a [[cosmological argument]] and an ontological argument. "It is ontological insofar as ‘necessary existence’ in intellect is the first basis for arguing for a Necessary Existent". The proof is also "cosmological insofar as most of it is taken up with arguing that contingent existents cannot stand alone and must end up in a Necessary Existent."<ref>{{citation|first=Toby|last=Mayer|title=Ibn Sina's 'Burhan Al-Siddiqin'|year=2001|journal=Journal of Islamic Studies|publisher=[[Oxford Centre for Islamic Studies]], Oxford Journals, Oxford University Press|volume=12|issue=1|pages=18–39|doi=10.1093/jis/12.1.18}}</ref>

===Distinction between essence and existence===
Islamic philosophy, imbued as it is with [[Kalam|Islamic theology]], distinguishes more clearly than [[Aristotelianism]] the difference between [[essence]] and [[existence]]. Whereas existence is the domain of the [[Contingency (philosophy)|contingent]] and the accidental, essence endures within a [[being]] beyond the accidental. This was first described by [[Avicenna]]'s works on [[metaphysics]], who was himself influenced by [[al-Farabi]].

Some ''orientalists'' (or those particularly influenced by Thomist scholarship) argued that Avicenna was the first to view existence (''wujud'') as an accident that happens to the essence (''mahiyya'').  However, this aspect of ontology is not the most central to the distinction that Avicenna established between essence and existence.  One cannot therefore make the claim that Avicenna was the proponent of the concept of [[essentialism]] ''per se'', given that existence (''al-wujud'') when thought of in terms of necessity would ontologically translate into a notion of the ''Necessary-Existent-due-to-Itself'' (''wajib al-wujud bi-dhatihi''), which is without description or definition, and particularly without quiddity or essence (''la mahiyya lahu'').  Consequently, Avicenna's ontology is '[[Existentialism|existentialist]]' when accounting for being qua existence in terms of necessity (''wujub''), while it is '[[Essentialism|essentialist]]' in terms of thinking about being qua existence (''wujud'') in terms of contingency qua possibility (''imkan''; or ''mumkin al-wujud'': contingent being).<ref>For recent discussions of this question see: Nader El-Bizri, "Avicenna and Essentialism", ''The Review of Metaphysics'', Vol. 54 (June 2001), pp. 753-778.</ref>

Some argue that Avicenna anticipated [[Frege]] and [[Bertrand Russell]] in "holding that existence is an accident of accidents" and also anticipated [[Alexius Meinong]]'s "view about [[nonexistent object]]s."<ref>{{citation|first=Herrera Ibáñez|last=Alejandro|title=La distinción entre esencia y existencia en Avicena|journal=Revista Latinoamericana de Filosofía|volume=16|pages=183–195|year=1990|url=http://www.formalontology.it/avicenna.htm|access-date=2008-01-29|archive-date=2010-01-16|archive-url=https://web.archive.org/web/20100116145842/http://www.formalontology.it/avicenna.htm|url-status=live}}</ref> He also provided early arguments for "a '[[Necessary and sufficient conditions|necessary]] being' as cause of all other existents."<ref>{{citation|first=Hourani George|last=Fadlo|title=Ibn Sina on necessary and possible existence|journal=Philosophical Forum|volume=4|pages=74–86|year=1972|url=http://www.formalontology.it/avicenna-biblio-one.htm|access-date=2008-01-29|archive-date=2008-02-26|archive-url=https://web.archive.org/web/20080226185534/http://www.formalontology.it/avicenna-biblio-one.htm|url-status=live}}</ref>

The idea of "essence precedes existence" is a concept which dates back to [[Avicenna]]<ref name=Irwin/> and his school of [[Avicennism]] as well as [[Shahab al-Din Suhrawardi]]<ref>{{Harv|Razavi|1997|p=129}}</ref> and his [[Illuminationist philosophy]]. The opposite idea of "[[existence precedes essence]]" was thus developed in the works of [[Averroes]]<ref name=Irwin/> and [[Mulla Sadra]]'s [[transcendent theosophy]].

More careful approaches are needed in terms of thinking about philosophers (and theologians) in Islam in terms of phenomenological methods of investigation in [[ontology]] (or onto-theology), or by way of comparisons that are made with [[Heidegger]]'s thought and his critique of the history of metaphysics.<ref>For recent studies that engage in this line of research with care and thoughtful deliberation, see: Nader El-Bizri, ''The Phenomenological Quest between Avicenna and Heidegger'' (Binghamton, N.Y.: Global Publications SUNY, 2000)</ref>

==== Wajib al-Wujud ====
Usually Muslims call God (Allah) "Wajib al-Wujud". It can be said; In general, the difference between the "Islamic view" and other views is not in the principle of "realism", but in the image it presents of the real world based on it. In "Islamic philosophy", while admitting material existence, "non-material" and abstract existence is also proven, and the existence of the Supreme Being or this title is defined as the essence of existence, which is the axis of the whole world.<ref>{{cite web | url=https://www.islamquest.net/fa/archive/fa50928 | title=نکات تشابه و اختلاف «رئالیسم غربی» و «رئالیسم اسلامی» در چیست؟ - گنجینه پاسخ ها }}</ref><ref>{{cite web | url=https://mail.islamquest.net/fa/archive/fa50928 | title=نکات تشابه و اختلاف «رئالیسم غربی» و «رئالیسم اسلامی» در چیست؟ - گنجینه پاسخ ها }}</ref><ref>{{cite web | url=https://www.islamquest.net/fa/archive/question/fa2359 | title=ازلی و ابدی بودن خداوند را از طریق عقل ثابت کنید؟ - گنجینه پاسخ ها }}</ref><ref>{{cite web | url=https://www.islamquest.net/fa/archive/question/fa39405 | title=به چه دلیل واجب الوجود باید واجد همه کمالات باشد؟ - گنجینه پاسخ ها }}</ref>

===Resurrection===
Ibn al-Nafis wrote the ''Theologus Autodidactus'' as a defense of "the system of Islam and the Muslims' doctrines on the missions of Prophets, the religious laws, the resurrection of the body, and the transitoriness of the world." The book presents rational arguments for bodily [[resurrection]] and the [[immortality]] of the human soul, using both demonstrative [[reasoning]] and material from the hadith corpus as forms of [[evidence]]. Later Islamic scholars viewed this work as a response to [[Avicenna]]'s [[Metaphysics|metaphysical]] argument on spiritual resurrection (as opposed to bodily resurrection), which was earlier criticized by [[al-Ghazali]].<ref>Fancy, p. 42 & 60</ref>

===Soul and spirit===
The [[Islamic medicine|Muslim physician]]-philosophers, [[Avicenna]] and [[Ibn al-Nafis]], developed their own theories on the soul. They both made a distinction between the soul and the spirit, and in particular, the [[Avicennism#Avicennian epistemology and psychology|Avicennian]] doctrine on the nature of the soul was influential among the [[Scholasticism|Scholastics]]. Some of Avicenna's views on the soul included the idea that the [[immortality]] of the soul is a consequence of its nature, and not a purpose for it to fulfill. In his theory of "The Ten Intellects", he viewed the human soul as the tenth and final [[intellect]].

Avicenna generally supported [[Aristotle]]'s idea of the soul originating from the [[heart]], whereas Ibn al-Nafis on the other hand rejected this idea and instead argued that the soul "is related to the entirety and not to one or a few [[organ (anatomy)|organ]]s." He further criticized Aristotle's idea that every unique soul requires the existence of a unique source, in this case the heart. Ibn al-Nafis concluded that "the soul is related primarily neither to the spirit nor to any organ, but rather to the entire matter whose temperament is prepared to receive that soul" and he defined the soul as nothing other than "what a human indicates by saying ‘[[I (pronoun)|I]]’."<ref>Nahyan A. G. Fancy (2006), "Pulmonary Transit and Bodily Resurrection: The Interaction of Medicine, Philosophy and Religion in the Works of Ibn al-Nafīs (d. 1288)", p. 209-210, ''Electronic Theses and Dissertations'', [[University of Notre Dame]].[http://etd.nd.edu/ETD-db/theses/available/etd-11292006-152615] {{Webarchive|url=https://web.archive.org/web/20150404020329/http://etd.nd.edu/ETD-db/theses/available/etd-11292006-152615/|date=2015-04-04}}</ref>

===Thought experiments===
{{Further|Avicennism}}

While he was imprisoned in the castle of Fardajan near [[Hamadhan]], [[Avicenna]] wrote his famous "Floating Man" [[thought experiment]] to demonstrate human [[self-awareness]] and the substantiality of the soul. He referred to the living human [[intelligence]], particularly the [[active intellect]], which he believed to be the [[Hypostatic abstraction|hypostasis]] by which God communicates truth to the human [[mind]] and imparts order and [[intelligibility (philosophy)|intelligibility]] to [[nature]]. His "Floating Man" thought experiment tells its readers to imagine themselves suspended in the air, isolated from all [[Wikt:sensation|sensations]], which includes no [[Sense|sensory]] contact with even their own bodies. He argues that, in this scenario, one would still have [[self-consciousness]]. He thus concludes that the idea of the [[Self (philosophy)|self]] is not logically dependent on any physical [[Object (philosophy)|thing]], and that the soul should not be seen in [[relative term]]s, but as a primary given, a [[Substance theory|substance]].<ref name=Leaman>Seyyed [[Hossein Nasr]] and [[Oliver Leaman]] (1996), ''History of Islamic Philosophy'', p. 315, Routledge, {{ISBN|0-415-13159-6}}.</ref>

This argument was later refined and simplified by [[René Descartes]] in [[epistemic]] terms when he stated: "I can abstract from the supposition of all external things, but not from the supposition of my own consciousness."<ref name=Leaman/>

===Time===
While ancient Greek philosophers believed that the universe had an infinite past with no beginning, early [[Medieval philosophy|medieval philosophers]] and theologians developed the concept of the universe having a [[Temporal finitism|finite past]] with a beginning. This view was inspired by the [[creationism]] shared by [[Judaism]], [[Christianity]] and [[Islam]]. The [[Christian philosophy|Christian philosopher]] [[John Philoponus]] presented a detailed argument against the ancient Greek notion of an infinite past. Muslim and Arab Jewish philosophers like [[Al-Kindi]], [[Saadia Gaon]], and [[Al-Ghazali]] developed further arguments, with most falling into two broad categories: assertions of the "impossibility of the existence of an actual infinite" and of the "impossibility of completing an actual infinite by successive addition".<ref name=Craig>{{citation |title=Whitrow and Popper on the Impossibility of an Infinite Past |first=William Lane |last=Craig |journal=The British Journal for the Philosophy of Science |volume=30 |issue=2 |date=June 1979 |pages=165–70 [165–66] |doi=10.1093/bjps/30.2.165}}</ref>

===Truth===
In [[metaphysics]], [[Avicenna]] (Ibn Sina) defined truth as:

{{blockquote|"What corresponds in the mind to what is outside it."<ref>Osman Amin (2007), "Influence of Muslim Philosophy on the West", ''Monthly Renaissance'' '''17''' (11).</ref>}}

Avicenna elaborated on his definition of truth in his ''[[Metaphysics]]'':

{{blockquote|"The truth of a thing is the property of the being of each thing which has been established in it."<ref name=Aertsen>Jan A. Aertsen (1988), ''Nature and Creature: Thomas Aquinas's Way of Thought'', p. 152. Brill, {{ISBN|90-04-08451-7}}.</ref>}}

In his ''Quodlibeta'', [[Thomas Aquinas]] wrote a commentary on Avicenna's definition of truth in his ''Metaphysics'' and explained it as follows:

{{blockquote|"The truth of each thing, as Avicenna says in his ''Metaphysica'', is nothing else than the property of its being which has been established in it. So that is called true gold which has properly the being of gold and attains to the established determinations of the nature of gold. Now, each thing has properly being in some nature because it stands under the complete form proper to that nature, whereby being and species in that nature is."<ref name=Aertsen/>}}

Early [[#Political philosophy|Islamic political philosophy]] emphasized an inexorable link between science and religion and emphsized the process of [[ijtihad]] to find truth.

[[Ibn al-Haytham]] (Alhacen) reasoned that to discover the truth about nature, it is necessary to eliminate human opinion and error, and allow the universe to speak for itself.<ref name="Ibn Al-Haytham">{{Cite news|url=http://www.ibnalhaytham.com/discover/who-was-ibn-al-haytham/|title=Who was Ibn al-Haytham - Ibn Al-Haytham|work=Ibn Al-Haytham|access-date=2018-01-19|language=en-US|archive-date=2018-01-29|archive-url=https://web.archive.org/web/20180129082341/http://www.ibnalhaytham.com/discover/who-was-ibn-al-haytham/|url-status=live}}</ref> In his ''Aporias against Ptolemy'', Ibn al-Haytham further wrote the following comments on truth:

{{blockquote|"Truth is sought for itself [but] the truths, [he warns] are immersed in uncertainties [and the scientific authorities (such as Ptolemy, whom he greatly respected) are] not immune from error..."<ref name=Sabra/>}}

{{blockquote|"Therefore, the seeker after the truth is not one who studies the writings of the ancients and, following his natural disposition, puts his trust in them, but rather the one who suspects his faith in them and questions what he gathers from them, the one who submits to argument and demonstration, and not to the sayings of a human being whose nature is fraught with all kinds of imperfection and deficiency. Thus the duty of the man who investigates the writings of scientists, if learning the truth is his goal, is to make himself an enemy of all that he reads, and, applying his mind to the core and margins of its content, attack it from every side. He should also suspect himself as he performs his critical examination of it, so that he may avoid falling into either prejudice or leniency."<ref name=Sabra/>}}

{{blockquote|"I constantly sought knowledge and truth, and it became my belief that for gaining access to the [[Wiktionary:effulgence|effulgence]] and closeness to God, there is no better way than that of searching for truth and knowledge."<ref name=Plott/>}}