Karl Leonhard Reinhold (; ; 26 October 1757 – 10 April 1823) was an Austrian

philosopher Philosophy ('love of wisdom' in Ancient Greek) is a systematic study of general and fundamental questions concerning topics like existence, reason, knowledge, Value (ethics and social sciences), value, mind, and language. It is a rational an ...

who helped to popularise the work of

Immanuel Kant Immanuel Kant (born Emanuel Kant; 22 April 1724 – 12 February 1804) was a German Philosophy, philosopher and one of the central Age of Enlightenment, Enlightenment thinkers. Born in Königsberg, Kant's comprehensive and systematic works ...

in the late 18th century. His "elementary philosophy" (''Elementarphilosophie'') also influenced

German idealism German idealism is a philosophical movement that emerged in Germany in the late 18th and early 19th centuries. It developed out of the work of Immanuel Kant in the 1780s and 1790s, and was closely linked both with Romanticism and the revolutionary ...

, notably

Johann Gottlieb Fichte Johann Gottlieb Fichte (; ; 19 May 1762 – 29 January 1814) was a German philosopher who became a founding figure of the philosophical movement known as German idealism, which developed from the theoretical and ethical writings of Immanuel Ka ...

, as a critical system grounded in a fundamental first principle. He was the father of Ernst Christian Gottlieb Reinhold (1793–1855), also a philosopher.

Life

Reinhold was born in

Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...

. In late 1772, at the age of fourteen, he entered the

Jesuit The Society of Jesus (; abbreviation: S.J. or SJ), also known as the Jesuit Order or the Jesuits ( ; ), is a religious order (Catholic), religious order of clerics regular of pontifical right for men in the Catholic Church headquartered in Rom ...

college (

Roman Catholic The Catholic Church (), also known as the Roman Catholic Church, is the largest Christian church, with 1.27 to 1.41 billion baptized Catholics worldwide as of 2025. It is among the world's oldest and largest international institut ...

seminary A seminary, school of theology, theological college, or divinity school is an educational institution for educating students (sometimes called seminarians) in scripture and theology, generally to prepare them for ordination to serve as cle ...

) of

St. Anne's Church, Vienna St. Anne's Church () is located in Vienna, Austria, and has been administered by the Oblates of St. Francis de Sales since 1906. A relic of Saint Anne—her right hand—is kept in a rich Baroque setting and exhibited every year on July 26. Hi ...

(Jesuitenkollegium St. Anna). He studied there for a year, until the order was suppressed in 1773, at which time he joined a similar Viennese Catholic college of the

Barnabites The Barnabites (), officially named as the Clerics Regular of Saint Paul (), are a religious order of clerics regular founded in 1530 in the Catholic Church. They are associated with the Angelic Sisters of Saint Paul and the members of the Ba ...

, the Barnabitenkollegium St. Michael. In 1778, he became a teacher at the Barnabitenkollegium, on 27 August 1780, he was ordained as a

Catholic priest The priesthood is the office of the ministers of religion, who have been commissioned ("ordained") with the holy orders of the Catholic Church. Technically, bishops are a priestly order as well; however, in common English usage ''priest'' refe ...

, and on 30 April 1783, he became a member of the Viennese

Freemasons' lodge A Masonic lodge (also called Freemasons' lodge, or private lodge or constituent lodge) is the basic organisational unit of Freemasonry. It is also a commonly used term for a building where Freemasons meet and hold their meetings. Every new l ...

"Zur wahren Eintracht."Karl Leonhard Reinhold, ''Essay on a New Theory of the Human Capacity for Representation'', Walter de Gruyter, 2011, p. x. Finding himself out of sympathy with monastic life, he fled on 19 November 1783 to

Leipzig Leipzig (, ; ; Upper Saxon: ; ) is the most populous city in the States of Germany, German state of Saxony. The city has a population of 628,718 inhabitants as of 2023. It is the List of cities in Germany by population, eighth-largest city in Ge ...

, where he converted to

Protestantism Protestantism is a branch of Christianity that emphasizes Justification (theology), justification of sinners Sola fide, through faith alone, the teaching that Salvation in Christianity, salvation comes by unmerited Grace in Christianity, divin ...

. In 1784, after studying philosophy for a semester at

, he settled in

Weimar Weimar is a city in the state (Germany), German state of Thuringia, in Central Germany (cultural area), Central Germany between Erfurt to the west and Jena to the east, southwest of Leipzig, north of Nuremberg and west of Dresden. Together w ...

, where he became

Christoph Martin Wieland Christoph Martin Wieland (; ; 5 September 1733 – 20 January 1813) was a German poet and writer, representative of literary Rococo. He is best-remembered for having written the first ''Bildungsroman'' (''Geschichte des Agathon''), as well as the ...

's collaborator on the ''German Mercury'' (''

Der Teutsche Merkur ''Der Teutsche Merkur'' (English: ''The German Mercury'') was a literary magazine published and edited by Christoph Martin Wieland. The magazine was modeled on French magazine, ''Mercure de France''. The first issue appeared in 1773. Wieland publ ...

''), and eventually his son-in-law. Reinhold married Wieland's daughter Sophia Catharina Susanna Wieland (19 October 1768 – 1 September 1837) on 18 May 1785. In the ''German Mercury'' Reinhold published, in the years 1786–87, his ''Briefe über die Kantische Philosophie'' (''Letters on the Kantian Philosophy''), which were most important in making

known to a wider circle of readers. As a result of these ''Letters'', Reinhold received a call to the

University of Jena The University of Jena, officially the Friedrich Schiller University Jena (, abbreviated FSU, shortened form ''Uni Jena''), is a public research university located in Jena, Thuringia, Germany. The university was established in 1558 and is cou ...

, where he taught from 1787 to 1794. In 1788, Reinhold published ''Hebräischen Mysterien oder die älteste religiöse Freymaurerey