“Religion, Society, and Nature! these are the three struggles of man.”
Hugo frames human life as involving simultaneous struggles with belief, social institutions and the physical world.
Source details
Toilers of the Sea, Preface, represented by Project Gutenberg #32338 in W. Moy Thomas's English translation. 'Religion, Society, and Nature! these are the three struggles of man' opens Hugo's triadic framing of Notre-Dame de Paris, Les Misérables and Toilers of the Sea. It is translated authorial/literary framing, not a social-scientific taxonomy of every human struggle.