Johannes Fredericus Schweitzer

First name
Johannes Fredericus
Last name
Date of Birth
Date of Death
Born in
Died in
The Hague

Johannes Fredericus Schweitzer, a Dutch anti-Cartesian physician and alchemist, studied medicine (1656) at Harderwijk University. He graduated on a disputation on the plague (De peste), and practised in The Hague (from 1662 onwards). Schweitzer wrote against Descartes and Spinoza in Philosophia theologica contra Cartesii et Spinosae theologiam philosophicam, ofte de ontmenschte mensch (Amsterdam, 1680) and in Adams oud graf met Cartesiaansche, Coccejaansche en Spinosistische doodsbeenderen gevuld (The Hague, 1687). See: Krul, 1893; NNBW, vol. 3, cols 570–2; Lindeboom,1984, cols 827–8.

Around 1667, rumor had it that Schweitzer had successfully effected a transmutation of lead into gold. Spinoza went to Isaac Vossius to ask his opinion about this story. When Spinoza visited Vossius, it soon turned out that the latter scholar (and Christiaan Huygens with him) was critical of Schweitzer’s abilities as a physician and he saw his qualities as an alchemist probably in the same light of mistrust. From his reaction to Spinoza’s questions about the alleged transmutation, it turns out that Vossius judged the whole story and Schweitzer’s predilection for alchemy to be one big mischievous deception. Moreover, a letter to Jelles of the 25th informs us that he even made fun of Spinoza’s fascination for the story of Schweitzer (1667.03.25, Ep 40). When I asked Vossius to give a comment on the rumour, Spinoza informs his Amsterdam correspondent, he ‘laughed heartily and was surprised that I would ask him about these trifles’.


Christiaan Huygens


Benedictus Spinoza, de


Isaac Vossius