Johann Hasler

He is known for his association with a group of antitrinitarians including Johann Sylvan and Adam Neuser and for developing Galen's concept of heat and cold into the idea of a scale of temperature.

While in Strasbourg, Hasler produced his first published work Aphorismi Thetici Aristotelei, a thesis which attempted a synthesis between philosophy and theology, reason and revelation.

During the next few years he spent time in Freiburg, where he received his medical doctorate, Lithuania as a family tutor, and Augsburg, where his two next important works De Logistica Medica, and Tabula aphoristica were published in 1578.

A letter from Thomas Erastus in 1574 notes that "his arrogance and ambition gave grounds for concern" and that he was "capable of defending whichever side of an argument pleased him".

[2] But although he came under suspicion on several occasions, there was never sufficient evidence of serious deviations from the orthodoxy of the Lutheran establishment in Bern, and he generally retained the support of the city fathers, who had sponsored his studies.

The most important dispute was over the Aphorismi in 1574–1575, which dealt with arguments for natural knowledge of God (including the doctrine of the Trinity) based on Aristotle's Metaphysics.

"[3] He was criticised for claiming that philosophy should be used to moderate religion, which implied that the divine revelation in the scriptures was not a sufficient basis for theology.

Hasler's works also included comprehensive catalogues of medical substances categorised according to their properties of temperature and humidity, and astrological calendars.