Johann Friedrich Gensichen

Johann Friedrich Gensichen (born January 30, 1760 in Driesen , † September 7, 1807 in Königsberg ) was a friend of Immanuel Kant .

Life

Gensichen's father was a pastor, his mother a sister of Johann Timotheus Hermes. This had been feuded by Goethe and Schiller in the "Xenienstreit".

To study Gensichen went to Königsberg, where his uncle worked in the church administration. After completing his studies, Gensichen first became a private tutor for two Dönhoff sons who grew up 20 km southeast of Königsberg. He later met her again as a student in Königsberg - often with the court preacher and mathematics professor Johann Schultz.

Between 1769 and 1775 Schultz was pastor in Löwenhagen, the church of the Dönhoff family. He was later called to Königsberg - as a pastor and later also as a full professor of mathematics. Between 1780 and 1806 he wrote books and articles on the completely new topic "The mathematics of infinity". Other books by Schultz show him as a committed understanding of Kant.

Gensichen often took part in parties, discussion and game evenings at the Schultz house.

Since 1790/91 he has given mathematics lectures; In 1795 he became an associate professor of mathematics. Professor Christian Jakob Kraus lent him the (large) sum of money that he had to pay in as a deposit.

From 1791 Gensichen was head of the (only) Königsberg student residence. Later he also became the second librarian of the university library - and finally rendant of the entire university.

Gensichen and Kant: a friendship

When Gensichen returned to Königsberg in 1791, Kant asked him to update the "sky theory" from 1755 to the latest state of astronomy. Gensichen took on the task - although he also modernized the language of the book. This is how an authentic excerpt from Kant's theory of heaven was created for “On the Building of Heaven” (1791) - together with contributions by Wilhelm Herschel. Pastor Georg Michael Sommer translated these from English.

Since then and until Kant's month of death, Gensichen was one of his lunch guests.

Kant had named Gensichen as his main heir in an early testament. Pastor Wasianski later pushed his way into Kant's housekeeping and dominated them. He managed to get Kant to make several changes in the will in Wasianski's favor, while Gensichen's share was considerably reduced. After all, Gensichen inherited - in addition to some money - Kant's pocket watch and Bible and around 400 books from Kant's library. 

On September 7th, 1807 he died of "nervous fever" (typhus), which had been carried into the student residence mentioned by French and Russian soldiers.

The theology student Samuel Neumann, to whom Gensichen had given Kant's Bible, gave the funeral sermon.

A catalog of the books and notebooks Gensichen left behind was printed. It also lists a number of piano notes. There was an instrument in his apartment.

Publications

Gensichen's first book "Confirmation of the Schultzische theory of parallels ..." appeared during his time as a tutor.

Later he wrote some (mostly anonymously published) reviews. For example, two reviews of Fichte's revelation criticism: the first evaluations of the book at all. (Fichte had lived in Königsberg for a few months and made friends with Gensichen.) - Strong evidence suggests that Gensichen was also the reviewer of Schultzen's “Attempt at an Exact Theory of Infinity” from 1788. This review contains Königsberger insider knowledge - and Schultzen's book is criticized only very moderately. In the book itself you can also find some additions to the content of Gensichens.

Several authors contributed to the other book ("On the Construction of Heaven"). At the center, however, is Gensichens's new version of Kant's theory of heaven.

In the directory of Gensichen's books (= auction catalog) from 1808 there is a striking number of writings (booklets) on arithmetic: own manuscripts “ad suas ideas” - and by other authors.

In 1898 - decades after Kant's death - scientists believed a retrieved 1791 Gensichen manuscript of the sky theory to be "by Kant's hand". Wilhelm Dilthey wrote in the "National-Zeitung" on November 11, 1898 that he had found "Changes in Kant's Hand" in the manuscript. In fact, no traces of Kant's “hand” can be found in it. Everything in the paper comes from Gensichen.

Later effects

The later development of mathematics is also due to the effects of Gensichen and Schultzen's mathematical work: In Prague, Bernard Bolzano (1781–1848) took up Königsberger impulses and named Gensichen several times. Cantor owned Bolzano's book. He sent it to Dedekind - who, when he presented his new definition of infinitely large quantities, referred to Bolzano's preparatory work.

literature

• Abegg, Johann Friedrich: travel diary from 1798, ed. v. W. u. J. Abegg, Frankfurt a. M. 1976.
• Bolzano, Bernard: Paradoxes of the Infinite, Leipzig 1851.
• Dedekind, Richard: What are and what are the numbers? 4th edition 1918.
• Fichte, Johann Gottlieb: Post-processed writings from the Bavarian Academy of Sciences 1780–1791, Bad Cannstatt 1962, p. 417.
• Gensichen, Johann Friedrich: Confirmation of the Schultzischen. Theory of parallels and refutation of Bendavid's treatise on the parallel lines. One try. Koenigsberg 1786.
• Gensichen, Otto Franz. A family of pastors from the Brandenburg region. In: Neue Preußische (Kreuz-) Zeitung No. 457 of November 11, 1888, p. 1.
• Gensichen, Hans-Peter: The young friend of the old Kant. Norderstedt 2017, especially p. 9f + 161.
• Herschel, William; Gensichen, Johann Friedrich; Sommer, Georg Michael: About the construction of the sky. Drey's treatises translated from English. Along with an authentic excerpt from Kant's general natural history and theory of heaven. Koenigsberg 1791.
• Reusch, Christian Friedrich: Kant and his table companions, Königsberg after 1847.
• Schubrig, Gerd: Approaches to the foundation of theoretical terms in mathematics. The theory of infinity by Johann Schultz (1739–1805). In: Historia Mathematica 9 (4), 441-484.
• Schultz, Johann: Examination of the Kantian Criticism of Pure Reason, 1. Part, 1789 a. 1791. 
• Stark, Werner: Research on letters and manuscripts by Immanuel Kant. Berlin 1993.
• Directory of the books of the deceased Professor Johann Friedrich Gensichen, which also includes the books of Professor Kant that had fallen to him ... Königsberg 1808; Reprint: Amsterdam 1968.