Conversation so far:
What is We Have Never Been Modern?
We Have Never Been Modern is a 1991 book by Bruno Latour, originally published in French as Nous n'avons jamais été modernes : Essai d'anthropologie symétrique.
What did Bruno Latour mean by We have never been modern?
Bruno Latour argued that society has never really been modern and promoted nonmodernism over postmodernism, modernism, or antimodernism.
What did Bruno Latour think we needed to re-think and re-evaluate?
Latour encouraged the reader of this anthropology of science to re-think and re-evaluate our mental landscape.

Question: What was his definition of modern?
Self-contained rewrite: What was Bruno Latour's definition of modern?