Editing Rationalism (section)

==History==
===Rationalist philosophy in Western antiquity===
[[File:Pythagoras with tablet of ratios.jpg|thumb|Detail of Pythagoras with a tablet of ratios, numbers sacred to the Pythagoreans, from ''[[The School of Athens]]'' by [[Raphael]]. [[Vatican Palace]], [[Vatican City]]]]
Although rationalism in its modern form post-dates antiquity, philosophers from this time laid down the foundations of rationalism. In particular, the understanding that we may be aware of knowledge available only through the use of rational thought.{{Citation needed|date=April 2018}}

====Pythagoras (570–495 BCE)====
{{Main|Pythagoras}}
Pythagoras was one of the first Western philosophers to stress rationalist insight.<ref name="Epistemological rationalism in modern philosophies">{{Cite web|url=https://www.britannica.com/topic/rationalism|title=rationalism &#124; Definition, Types, History, Examples, & Descartes|website=Encyclopædia Britannica|date=28 May 2023|access-date=14 May 2021|archive-date=18 May 2015|archive-url=https://web.archive.org/web/20150518105808/https://www.britannica.com/EBchecked/topic/492034/rationalism|url-status=live}}</ref> He is often revered as a great [[mathematician]], [[mysticism|mystic]] and [[scientist]], but he is best known for the [[Pythagorean theorem]], which bears his name, and for discovering the mathematical relationship between the length of strings on lute and the pitches of the notes. Pythagoras "believed these harmonies reflected the ultimate nature of reality. He summed up the implied metaphysical rationalism in the words 'All is number'. It is probable that he had caught the rationalist's vision, later seen by [[Galileo Galilei|Galileo]] (1564–1642), of a world governed throughout by mathematically formulable laws".<ref name="Epistemological rationalism in ancient philosophies">{{Cite web|url=https://www.britannica.com/topic/rationalism|title=rationalism &#124; Definition, Types, History, Examples, & Descartes &#124; Britannica|website=www.britannica.com|date=28 May 2023|access-date=14 May 2021|archive-date=18 May 2015|archive-url=https://web.archive.org/web/20150518105808/https://www.britannica.com/EBchecked/topic/492034/rationalism|url-status=live}}</ref> It has been said that he was the first man to call himself a philosopher, or lover of wisdom.<ref>[[Cicero]], ''[[Tusculan Disputations]]'', 5.3.8–9 = [[Heraclides Ponticus]] fr. 88 Wehrli, [[Diogenes Laërtius]] 1.12, 8.8, [[Iamblichus]] ''VP'' 58. Burkert attempted to discredit this ancient tradition, but it has been defended by [[C.J. de Vogel]], ''Pythagoras and Early Pythagoreanism'' (1966), pp. 97–102, and C. Riedweg, ''Pythagoras: His Life, Teaching, And Influence'' (2005), p. 92.</ref>

====Plato (427–347 BCE)====
{{Main|Plato}}
[[File:Plato by Raphael.png|thumb|[[Plato]] in ''[[The School of Athens]]'', by [[Raphael]]]]
Plato held rational insight to a very high standard, as is seen in his works such as [[Meno]] and [[The Republic (Plato)|The Republic]]. He taught on the [[Theory of Forms]] (or the Theory of Ideas)<ref>Modern English textbooks and translations prefer "Theory of Forms" to "Theory of Ideas", but the latter has a long and respected tradition starting with Cicero and continuing in German philosophy until present, and some English philosophers prefer this in English too. See W. D. Ross, Plato's Theory of Ideas (1951) and [http://www.philosophyprofessor.com/philosophies/platos-theory-of-forms.php this]{{webarchive|url=https://web.archive.org/web/20110927061811/http://www.philosophyprofessor.com/philosophies/platos-theory-of-forms.php|date=2011-09-27}} reference site.</ref><ref>The name of this aspect of Plato's thought is not modern and has not been extracted from certain dialogues by modern scholars. The term was used at least as early as [[Diogenes Laërtius]], who called it (Plato's) "Theory of Forms:" {{lang|grc|Πλάτων ἐν τῇ περὶ τῶν ἰδεῶν ὑπολήψει}}...., {{cite encyclopedia |title=Plato |encyclopedia=Lives of Eminent Philosophers |volume=Book III Paragraph 15 |pages=}}</ref><ref>Plato uses many different words for what is traditionally called ''form'' in English translations and ''idea'' in German and Latin translations (Cicero). These include ''idéa'', ''morphē'', ''eîdos'', and ''parádeigma'', but also ''génos'', ''phýsis'', and ''[[Ousia|ousía]]''. He also uses expressions such as ''to x auto'', "the x itself" or ''kath' auto'' "in itself". See Christian Schäfer: ''Idee/Form/Gestalt/Wesen'', in ''Platon-Lexikon'', Darmstadt 2007, p. 157.</ref> which asserts that the highest and most fundamental kind of reality is not the material world of change [[allegory of the cave|known to us through sensation]], but rather the abstract, non-material (but [[Ousia|substantial]]) world of forms (or ideas).<ref>''Forms (usually given a capital F) were properties or essences of things, treated as non-material abstract, but substantial, entities. They were eternal, changeless, supremely real, and independent of ordinary objects that had their being and properties by 'participating' in them.'' [http://www.philosophyprofessor.com/philosophies/platos-theory-of-forms.php Plato's theory of forms (or ideas)] {{webarchive|url=https://web.archive.org/web/20110927061811/http://www.philosophyprofessor.com/philosophies/platos-theory-of-forms.php|date=2011-09-27}}.</ref> For Plato, these forms were accessible only to reason and not to sense.<ref name="Epistemological rationalism in ancient philosophies"/> In fact, it is said that Plato admired reason, especially in [[geometry]], so highly that he had the phrase "Let no one ignorant of geometry enter" inscribed over the door to his academy.<ref>{{cite web|url=http://plato-dialogues.org/faq/faq009.htm|title=Plato FAQ: "Let no one ignorant of geometry enter"|first=Bernard F.|last=Suzanne|website=plato-dialogues.org|access-date=2013-05-22|archive-date=2013-05-19|archive-url=https://web.archive.org/web/20130519153541/http://plato-dialogues.org/faq/faq009.htm|url-status=live}}</ref>

====Aristotle (384–322 BCE)====
{{Main|Aristotle}}
[[Aristotle]]'s main contribution to rationalist thinking was the use of [[Syllogism|syllogistic]] logic and its use in argument. Aristotle defines syllogism as "a discourse in which certain (specific) things having been supposed, something different from the things supposed results of necessity because these things are so."<ref>[[Aristotle]], ''Prior Analytics'', 24b18–20.</ref> Despite this very general definition, Aristotle limits himself to categorical syllogisms which consist of three [[categorical proposition]]s in his work ''[[Prior Analytics]]''.<ref>[http://plato.stanford.edu/entries/logic-ancient/#SynSemSen] {{Webarchive|url=https://web.archive.org/web/20180828102117/https://plato.stanford.edu/entries/logic-ancient/#SynSemSen|date=2018-08-28}} Stanford Encyclopedia of Philosophy: ''Ancient Logic'' Aristotle Non-Modal Syllogistic.</ref> These included categorical [[modal logic|modal]] syllogisms.<ref>[http://plato.stanford.edu/entries/logic-ancient/#ModLog] {{Webarchive|url=https://web.archive.org/web/20180828102117/https://plato.stanford.edu/entries/logic-ancient/#ModLog|date=2018-08-28}} Stanford Encyclopedia of Philosophy: ''Ancient Logic'' Aristotle Modal Logic.</ref>

===Middle Ages===
[[File:Avicenna Portrait on Silver Vase - Museum at BuAli Sina (Avicenna) Mausoleum - Hamadan - Western Iran (7423560860).jpg|thumb|[[Ibn Sina]] Portrait on Silver Vase]]
Although the three great Greek philosophers disagreed with one another on specific points, they all agreed that rational thought could bring to light knowledge that was self-evident{{snd}}information that humans otherwise could not know without the use of reason. After Aristotle's death, Western rationalistic thought was generally characterized by its application to theology, such as in the works of [[Augustine of Hippo|Augustine]], the [[Islamic philosopher]] [[Avicenna|Avicenna (Ibn Sina)]], [[Averroes|Averroes (Ibn Rushd)]], and Jewish philosopher and theologian [[Maimonides]]. The [[Waldensians]] sect also incorporated rationalism into their movement.<ref name="Heckethorn 2011 p. 139">{{cite book | last=Heckethorn | first=C.W. | title=The Secret Societies of All Ages & Countries (Two Volumes in One) | publisher=Cosimo Classics | year=2011 | isbn=978-1-61640-555-7 | url=https://books.google.com/books?id=ta-GttanhRYC&pg=PA139 | access-date=2023-02-11 | page=139 | archive-date=2023-02-11 | archive-url=https://web.archive.org/web/20230211004210/https://books.google.com/books?id=ta-GttanhRYC&pg=PA139 | url-status=live }}</ref> One notable event in the Western timeline was the philosophy of [[Thomas Aquinas]] who attempted to merge Greek rationalism and Christian revelation in the thirteenth-century.<ref name="Epistemological rationalism in ancient philosophies"/><ref name="Gill">{{cite book|last=Gill|first=John|title=Andalucía : a cultural history|year=2009|publisher=[[Oxford University Press]]|location=Oxford|isbn=978-0195376104|pages=108–110}}</ref> Generally, the [[Roman Catholic Church]] viewed Rationalists as a threat, labeling them as those who "while admitting revelation, reject from the word of God whatever, in their private judgment, is inconsistent with human reason."<ref>{{cite book|chapter=[[s:Sermons from the Latins/Sermon 26|Low Sunday: Rationalism]] |title=Sermons from the Latins|year=1902|publisher= Benziger Brothers|first=Robert|last=Bellarmine|author-link=Robert Bellarmine}}</ref>

===Classical rationalism===
====René Descartes (1596–1650)====
{{Descartes}}
{{Main|René Descartes}}
Descartes was the first of the modern rationalists and has been dubbed the 'Father of Modern Philosophy.' Much subsequent [[Western philosophy]] is a response to his writings,<ref>[[Bertrand Russell]] (2004) [https://books.google.com/books?id=Ey94E3sOMA0C&pg=PA516 ''History of western philosophy''] {{Webarchive|url=https://web.archive.org/web/20231018123108/https://books.google.com/books?id=Ey94E3sOMA0C&pg=PA516 |date=2023-10-18 }} pp. 511, 516–517</ref><ref>Heidegger [1938] (2002) p. 76 "Descartes... that which he himself founded... modern (and that means, at the same time, Western) metaphysics".</ref><ref name="Britannica">{{cite encyclopedia |first1=Richard A. |last1=Watson |author-link1=Richard Watson (philosopher) |title=René Descartes |encyclopedia=Encyclopædia Britannica |publisher=Encyclopædia Britannica Online. Encyclopædia Britannica Inc |date=31 March 2012 |url=http://www.britannica.com/EBchecked/topic/158787/Rene-Descartes |access-date=31 March 2012 |archive-date=7 May 2015 |archive-url=https://web.archive.org/web/20150507222658/http://www.britannica.com/EBchecked/topic/158787/Rene-Descartes |url-status=live }}</ref> which are studied closely to this day.

Descartes thought that only knowledge of eternal truths{{snd}}including the truths of mathematics, and the epistemological and metaphysical foundations of the sciences{{spaced ndash}} could be attained by reason alone; other knowledge, the knowledge of physics, required experience of the world, aided by the [[scientific method]]. He also argued that although [[dream]]s appear as real as [[Empirical evidence|sense experience]], these dreams cannot provide persons with knowledge. Also, since conscious sense experience can be the cause of illusions, then sense experience itself can be doubtable. As a result, Descartes deduced that a rational pursuit of truth should doubt every belief about sensory reality. He elaborated these beliefs in such works as ''[[Discourse on the Method]]'', ''[[Meditations on First Philosophy]]'', and ''[[Principles of Philosophy]]''. Descartes developed a method to attain truths according to which nothing that cannot be recognised by the intellect (or [[reason]]) can be classified as knowledge. These truths are gained "without any sensory experience", according to Descartes. Truths that are attained by reason are broken down into elements that intuition can grasp, which, through a purely deductive process, will result in clear truths about reality.

Descartes therefore argued, as a result of his method, that reason alone determined knowledge, and that this could be done independently of the senses. For instance, his famous dictum, ''[[cogito ergo sum]]'' or "I think, therefore I am", is a conclusion reached ''[[A priori and a posteriori|a priori]]'' i.e., prior to any kind of experience on the matter. The simple meaning is that doubting one's existence, in and of itself, proves that an "I" exists to do the thinking. In other words, doubting one's own doubting is absurd.<ref name="Epistemological rationalism in modern philosophies"/> This was, for Descartes, an irrefutable principle upon which to ground all forms of other knowledge. Descartes posited a metaphysical [[Cartesian dualism|dualism]], distinguishing between the substances of the human body ("''res extensa''") and the [[mind]] or soul ("''res cogitans''"). This crucial distinction would be left unresolved and lead to what is known as the [[mind–body problem]], since the two substances in the Cartesian system are independent of each other and irreducible.

====Baruch Spinoza (1632–1677)====
{{Main|Philosophy of Spinoza}}
The philosophy of [[Baruch Spinoza]] is a systematic, logical, rational philosophy developed in seventeenth-century [[Europe]].<ref name=tws9904>{{cite news
| author = Lisa Montanarelli (book reviewer)
| title = Spinoza stymies 'God's attorney'&nbsp;– Stewart argues the secular world was at stake in Leibniz face off
| newspaper = San Francisco Chronicle
| date = January 8, 2006
| url = http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/01/08/RVGO9GEOKH1.DTL
| access-date = 2009-09-08
| archive-date = 2009-09-03
| archive-url = https://web.archive.org/web/20090903233734/http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/01/08/RVGO9GEOKH1.DTL
| url-status = live
}}</ref><ref name=tws07dec212>{{cite web
|author = Kelley L. Ross
|title = Baruch Spinoza (1632–1677)
|quote = While for Spinoza all is God and all is Nature, the active/passive dualism enables us to restore, if we wish, something more like the traditional terms. Natura Naturans is the most God-like side of God, eternal, unchanging, and invisible, while Natura Naturata is the most Nature-like side of God, transient, changing, and visible.
|publisher = History of Philosophy As I See It
|year = 1999
|url = http://www.friesian.com/spinoza.htm
|access-date = 2009-12-07
|archive-date = 2012-01-04
|archive-url = https://web.archive.org/web/20120104193706/http://friesian.com/spinoza.htm
|url-status = live
}}</ref><ref name=tws07dec211>{{cite news
|author = Anthony Gottlieb
|title = God Exists, Philosophically
|quote = Spinoza, a Dutch Jewish thinker of the 17th century, not only preached a philosophy of tolerance and benevolence but actually succeeded in living it. He was reviled in his own day and long afterward for his supposed atheism, yet even his enemies were forced to admit that he lived a saintly life.
|publisher = The New York Times: Books
|date = July 18, 1999
|url = http://www.times.com/books/99/07/18/reviews/990718.18gottlit.html
|access-date = 2009-12-07
|archive-date = 2023-10-18
|archive-url = https://web.archive.org/web/20231018123108/https://archive.nytimes.com/www.nytimes.com/books/99/07/18/reviews/990718.18gottlit.html
|url-status = live
}}</ref> Spinoza's philosophy is a system of ideas constructed upon basic building blocks with an internal consistency with which he tried to answer life's major questions and in which he proposed that "God exists only philosophically."<ref name=tws07dec211/><ref name=tws908/> He was heavily influenced by Descartes,<ref name=tws07dec114>{{cite news
|author = Michael LeBuffe (book reviewer)
|title = Spinoza's Ethics: An Introduction, by Steven Nadler
|quote = Spinoza's Ethics is a recent addition to Cambridge's Introductions to Key Philosophical Texts, a series developed for the purpose of helping readers with no specific background knowledge to begin the study of important works of Western philosophy...
|publisher = University of Notre Dame
|date = 2006-11-05
|url = http://ndpr.nd.edu/review.cfm?id=8004
|access-date = 2009-12-07
|archive-date = 2011-06-15
|archive-url = https://web.archive.org/web/20110615071049/http://ndpr.nd.edu/review.cfm?id=8004
|url-status = dead
}}</ref> [[Euclid]]<ref name=tws908>{{cite news
| author = Anthony Gottlieb
| title = God Exists, Philosophically (review of "Spinoza: A Life" by Steven Nadler)
| publisher = The New York Times&nbsp;– Books
| date = 2009-09-07
| url = https://www.nytimes.com/books/99/07/18/reviews/990718.18gottlit.html
| access-date = 2009-09-07
| archive-date = 2009-04-17
| archive-url = https://web.archive.org/web/20090417015246/http://www.nytimes.com/books/99/07/18/reviews/990718.18gottlit.html
| url-status = live
}}</ref> and [[Thomas Hobbes]],<ref name=tws07dec114/> as well as theologians in the Jewish philosophical tradition such as [[Maimonides]].<ref name=tws07dec114/> But his work was in many respects a departure from the [[Judeo-Christian-Islamic]] tradition. Many of Spinoza's ideas continue to vex thinkers today and many of his principles, particularly regarding the [[emotions]], have implications for modern approaches to [[psychology]]. To this day, many important thinkers have found Spinoza's "geometrical method"<ref name=tws07dec211/> difficult to comprehend: [[Johann Wolfgang von Goethe|Goethe]] admitted that he found this concept confusing.{{Citation needed|date=June 2015}} His ''[[Masterpiece|magnum opus]]'', ''[[Ethics (Spinoza book)|Ethics]]'', contains unresolved obscurities and has a forbidding mathematical structure modeled on Euclid's geometry.<ref name=tws908/> Spinoza's philosophy attracted believers such as [[Albert Einstein]]<ref name=tws9903>{{cite news
| title = Einstein Believes in 'Spinoza's God'; Scientist Defines His Faith in Reply, to Cablegram From Rabbi Here. Sees a Divine Order But Says Its Ruler Is Not Concerned 'Wit Fates and Actions of Human Beings'.
| newspaper = The New York Times
| date = April 25, 1929
| url = http://select.nytimes.com/gst/abstract.html?res=F10B1EFC3E54167A93C7AB178FD85F4D8285F9
| access-date = 2009-09-08
| archive-date = 2011-05-13
| archive-url = https://web.archive.org/web/20110513034043/http://select.nytimes.com/gst/abstract.html?res=F10B1EFC3E54167A93C7AB178FD85F4D8285F9
| url-status = live
}}</ref> and much intellectual attention.<ref name=tws9902>{{cite news
| title = Spinoza, "God-Intoxicated Man"; Three Books Which Mark the Three Hundredth Anniversary of the Philosopher's Birth 'Blessed Spinoza. A Biography'. By Lewis Browne. 319 pp. New York: Macmillan. 'Spinoza. Liberator of God and Man'. By Benjamin De Casseres, 145 pp. New York: E. Wickham Sweetland. 'Spinoza'. By Frederick Kettner. Introduction by Nicholas Roerich, New Era Library. 255 pp. New York: Roerich Museum Press. 'Spinoza'
| newspaper = The New York Times
| date = November 20, 1932
| url = http://select.nytimes.com/gst/abstract.html?res=F40A14F83A5513738DDDA90A94D9415B828FF1D3
| access-date = 2009-09-08
| first = Percy
| last = Hutchison
| archive-date = 2010-03-26
| archive-url = https://web.archive.org/web/20100326014329/http://select.nytimes.com/gst/abstract.html?res=F40A14F83A5513738DDDA90A94D9415B828FF1D3
| url-status = live
}}</ref><ref name=tws9910>{{cite news
| title = Spinoza's First Biography Is Recovered; The Oldest Biography of Spinoza Edited with Translations, Introduction, Annotations, &c., by A. Wolf. 196 pp. New York: Lincoln Macveagh. The Dial Press.
| newspaper = The New York Times
| date = December 11, 1927
| url = http://select.nytimes.com/gst/abstract.html?res=F60D1EFF395C147A93C3A81789D95F438285F9
| access-date = 2009-09-08
| archive-date = 2010-03-26
| archive-url = https://web.archive.org/web/20100326014335/http://select.nytimes.com/gst/abstract.html?res=F60D1EFF395C147A93C3A81789D95F438285F9
| url-status = live
}}</ref><ref name=tws9901>{{cite news
| author = Irwin Edman
| title = The Unique and Powerful Vision of Baruch Spinoza; Professor Wolfson's Long-Awaited Book Is a Work of Illuminating Scholarship. (Book review) 'The Philosophy of Spinoza. By Henry Austryn Wolfson
| newspaper = The New York Times
| date = July 22, 1934
| url = http://select.nytimes.com/gst/abstract.html?res=FB0610FC395D13728DDDAB0A94DF405B848FF1D3
| access-date = 2009-09-08
| archive-date = 2010-03-26
| archive-url = https://web.archive.org/web/20100326020800/http://select.nytimes.com/gst/abstract.html?res=FB0610FC395D13728DDDAB0A94DF405B848FF1D3
| url-status = live
}}</ref><ref name=tws9908>{{cite news
| title = Roth Evaluates Spinoza
| newspaper = Los Angeles Times
| date = September 8, 1929
| url = https://pqasb.pqarchiver.com/latimes/access/370934682.html?dids=370934682:370934682&FMT=ABS&FMTS=ABS:AI&type=historic&date=Sep+08%2C+1929&author=&pub=Los+Angeles+Times&desc=ROTH+EVALUATES+SPINOZA&pqatl=google
| access-date = 2009-09-08
| first = M E
| last = Cummings
| archive-date = 2010-03-24
| archive-url = https://web.archive.org/web/20100324043102/http://pqasb.pqarchiver.com/latimes/access/370934682.html?dids=370934682:370934682&FMT=ABS&FMTS=ABS:AI&type=historic&date=Sep+08%2C+1929&author=&pub=Los+Angeles+Times&desc=ROTH+EVALUATES+SPINOZA&pqatl=google
| url-status = dead
}}</ref><ref name=tws9906>{{cite news
| author = Social News Books
| title = Tribute to Spinoza Paid by Educators; Dr. Robinson Extols Character of Philosopher, 'True to the Eternal Light Within Him.' Hailed as 'Great Rebel'; De Casseres Stresses Individualism of Man Whose Tercentenary Is Celebrated at Meeting.
| newspaper = The New York Times
| date = November 25, 1932
| url = http://select.nytimes.com/gst/abstract.html?res=F30D13F6355516738DDDAC0A94D9415B828FF1D3
| access-date = 2009-09-08
| archive-date = 2010-03-26
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====Gottfried Leibniz (1646–1716)====
{{Main|Gottfried Leibniz}}
Leibniz was the last major figure of seventeenth-century rationalism who contributed heavily to other fields such as [[metaphysics]], [[epistemology]], [[logic]], [[mathematics]], [[physics]], [[jurisprudence]], and the [[philosophy of religion]]; he is also considered to be one of the last "universal geniuses".<ref name="Gottfried Wilhelm Leibniz">Stanford Encyclopedia of Philosophy: [http://plato.stanford.edu/entries/leibniz/ Gottfried Wilhelm Leibniz] {{Webarchive|url=https://web.archive.org/web/20200805133308/http://plato.stanford.edu/entries/leibniz/ |date=2020-08-05 }}.</ref> He did not develop his system, however, independently of these advances. Leibniz rejected Cartesian dualism and denied the existence of a material world. In Leibniz's view there are infinitely many simple substances, which he called "[[Monadology|monads]]" (which he derived directly from [[Proclus]]).

Leibniz developed his theory of monads in response to both Descartes and [[Spinoza]], because the rejection of their visions forced him to arrive at his own solution. Monads are the fundamental unit of reality, according to Leibniz, constituting both inanimate and animate objects. These units of reality represent the universe, though they are not subject to the laws of causality or space (which he called "[[well-founded phenomenon|well-founded phenomena]]"). Leibniz, therefore, introduced his principle of [[pre-established harmony]] to account for apparent causality in the world.

====Immanuel Kant (1724–1804)====
{{Immanuel Kant}}
{{Main|Immanuel Kant}}
Kant is one of the central figures of modern [[philosophy]], and set the terms by which all subsequent thinkers have had to grapple. He argued that human perception structures natural laws, and that reason is the source of morality. His thought continues to hold a major influence in contemporary thought, especially in fields such as metaphysics, epistemology, ethics, political philosophy, and aesthetics.<ref>{{cite web |url=http://plato.stanford.edu/entries/kant/ |title=Immanuel Kant (Stanford Encyclopedia of Philosophy) |publisher=Plato.stanford.edu |date=20 May 2010 |access-date=2011-10-22 |archive-date=2012-01-12 |archive-url=https://web.archive.org/web/20120112123355/http://plato.stanford.edu/entries/kant/ |url-status=live }}</ref>

Kant named his brand of epistemology "[[Transcendental Idealism]]", and he first laid out these views in his famous work ''[[Critique of Pure Reason|The Critique of Pure Reason]]''. In it he argued that there were fundamental problems with both rationalist and empiricist dogma. To the rationalists he argued, broadly, that pure reason is flawed when it goes beyond its limits and claims to know those things that are necessarily beyond the realm of every possible experience: the [[existence of God]], free will, and the immortality of the human soul. Kant referred to these objects as "The Thing in Itself" and goes on to argue that their status as objects beyond all possible experience by definition means we cannot know them. To the empiricist, he argued that while it is correct that experience is fundamentally necessary for human knowledge, reason is necessary for processing that experience into coherent thought. He therefore concludes that both reason and experience are necessary for human knowledge. In the same way, Kant also argued that it was wrong to regard thought as mere analysis. "In Kant's views, [[A priori and a posteriori|a priori]] concepts do exist, but if they are to lead to the amplification of knowledge, they must be brought into relation with empirical data".<ref>{{Cite web|url=http://abyss.uoregon.edu/~js/glossary/rationalism.html|title=Rationalism|website=abyss.uoregon.edu|access-date=2013-05-22|archive-date=2012-12-27|archive-url=https://web.archive.org/web/20121227102857/http://abyss.uoregon.edu/~js/glossary/rationalism.html|url-status=dead}}</ref>

===Contemporary rationalism===
Rationalism has become a rarer label  of philosophers today; rather many different kinds of specialised rationalisms are identified. For example, [[Robert Brandom]] has appropriated the terms "rationalist expressivism" and "rationalist pragmatism" as labels for aspects of his programme in ''Articulating Reasons'', and identified "linguistic rationalism", the claim that the contents of propositions "are essentially what can serve as both premises and conclusions of inferences", as a key thesis of [[Wilfred Sellars]].<ref>''Articulating reasons'', 2000. Harvard University Press.</ref>

Outside of academic philosophy, some participants in the internet communities surrounding [[LessWrong]] and [[Slate Star Codex]] have described themselves as "rationalists" or the "[[rationalist community]]" in reference to [[rationality]], rather than rationalism.<ref>{{Cite web |title=Rationalist Movement – LessWrong |url=https://www.lesswrong.com/tag/rationalist-movement |access-date=2023-06-19 |website=www.lesswrong.com |language=en |archive-date=2023-06-17 |archive-url=https://web.archive.org/web/20230617203001/https://www.lesswrong.com/tag/rationalist-movement |url-status=live }}</ref><ref>{{Cite news |last=Metz |first=Cade |date=2021-02-13 |title=Silicon Valley's Safe Space |language=en-US |work=The New York Times |url=https://www.nytimes.com/2021/02/13/technology/slate-star-codex-rationalists.html |access-date=2023-06-19 |issn=0362-4331 |archive-date=2021-04-20 |archive-url=https://web.archive.org/web/20210420171731/https://www.nytimes.com/2021/02/13/technology/slate-star-codex-rationalists.html |url-status=live }}</ref><ref>{{cite book | url=https://books.google.com/books?id=YDbyDwAAQBAJ | isbn=9781474608800 | title=The Rationalist's Guide to the Galaxy: Superintelligent AI and the Geeks Who Are Trying to Save Humanity's Future | date=13 June 2019 | publisher=Orion | access-date=23 June 2023 | archive-date=18 May 2023 | archive-url=https://web.archive.org/web/20230518113258/https://books.google.com/books?id=YDbyDwAAQBAJ | url-status=live }}</ref> The term has also been used in this way by critics such as [[Timnit Gebru]].<ref>{{cite web | url=https://washingtonspectator.org/understanding-tescreal-silicon-valleys-rightward-turn/ | title=The Wide Angle: Understanding TESCREAL — Silicon Valley's Rightward Turn | date=May 2023 | access-date=2023-06-06 | archive-date=2023-06-06 | archive-url=https://web.archive.org/web/20230606223259/https://washingtonspectator.org/understanding-tescreal-silicon-valleys-rightward-turn/ | url-status=live }}</ref>