Joachim Jungius

Born: LŸbeck, 22 Oct. 1587

Died: Hamburg, 23 Sept. 1657

Joachim Jungius attended school in LŸbeck until 1605. From 1606 until 1608 he attended the University of Rostock, where he studied metaphysics. On leaving Rostock he entered the University of Giessen where he later received his M.A.

In 1609 he was appointed professor of mathematics at Giessen and he held this post until 1614 when he began to become interested in medicine. In 1616 he returned to the University of Rostock to study medicine. Three years later he received a medical degree from the University of Padua.

Thereafter Jungius held chairs of mathematics at the University of Rostock from 1624 to 1625 and again 1626 to 1628. For one year in 1625 he held the chair of medicine at the University of Helmstedt. In 1629 he moved to Hamburg where he was professor of natural science until 1640. As well as mathematics, Jungius was interested in natural science and the philosophy of science. In mathematics Jungius proved that the catenary is not a parabola (Galileo assumed it was). He was one of the first to use exponents to represent powers and he used mathematics as a model for the natural sciences.

The Logica Hamburgensis (1638) of Jungius presented late medieval theories and techniques of logic. He discussed valid oblique cases of arguments that do not fit into simpler forms of inference. For example The square of an even number is even; 6 is even; therefore, the square of 6 is even.

The oblique case of an even number had to be put into the subject position so that standard arguments could be used. The technique of dealing with such inferences involved rewriting a premise so that the term in the oblique case (for example, Òof an even numberÓ) would occur in the subject position and thus be amenable to standard syllogistic manipulation. Such arguments had in fact been noticed by Aristotle and were also treated in late medieval logic. Aristotle had also dealt with this type of logical argument.

The Logica Hamburgensis (1638) of Joachim Jung (also called Jungius or Junge) was one replacement for the ÒProtestantÓ logic of Melanchthon. Its chief virtue was the care with which late medieval theories and techniques were gathered and presented. Jung devoted considerable attention to valid arguments that do not fit into simpler, standard conceptions of the syllogism and immediate inference. Of special interest is his treatment of quantified relational arguments, then called ÒobliqueÓ syllogisms because of the oblique (non-nominative) case that is used to express them in Latin.