Bonnet stood on the cusp of modern experimental science and earlier speculative theorising. He was Saussure’s uncle, and with his wife, brought him up as if their own son. Réaumur was a formative influence — Bonnet started corresponding with him after reading his ‘History of Insects’. Spallanzani was a good friend, who stayed with Bonnet when he was able to leave Italy; they had shared ideas about the reproduction of organisms. Sénebier was one of Bonnet’s students, and Haller and Blumenbach correspondents. Although he was a major critic of Jean-Jacques Rousseau’s ‘Discourse on Inequality’, Rousseau never replied.