Weigan was the son of a surgeon and was born at Waiblingen in 1677. He studied theology at Württemberg but also took interest in anatomy and natural science. Weigen became a pastor and advocate of pietism in Leonberg. He took up this post in 1705. Weigan was influenced by the writings of Philipp Spener.
Weigen argued for a compassionate treatment of the animals from a Christian theological framework. In 1711, Weigen authored De Jure Hominis in Creaturas. It has been described as "the first work ever to deal with the topic of animal rights as a general theme." The book became known in Denmark and inspired Laurids Smith. It was republished in 2008.
- De Jure Hominis in Creaturas (1711)
- Sträter, Udo. (2011). Pietismus und Neuzeit: Ein Jahrbuch Zur Geschichte Des Neueren Protestantismus. Band 36 – 2010. Vandenhoeck & Ruprecht. pp. 120–123. ISBN 978-3-525-55908-6
- Herberhold, Mechthild; Sölling, Caspar. (2003). Menschenrechte für Menschenaffen?: Was Tier und Mensch unterscheidet. Bonifatius. p. 25. ISBN 9783897102637
- Seidel, Ulrich; Dietrich, Hans-Eberhard. (2019). An der Seite der Tiere: Christsein und ein neuer Umgang mit der Kreatur. Lit. pp. 102–103. ISBN 978-3-643-14288-7
- Ingesman, Per. (2016). Religion as an Agent of Change: Crusades – Reformation – Pietism. Brill Publishers. pp. 224–226. ISBN 978-90-04-30372-0