There is a summary on wikipedia of We Have Never Been Modern which says
Latour viewed modernism as an era that believed it had annulled the entire past in its wake. He presented the antimodern reaction as defending such entities as spirit, rationality, liberty, society, God, or even the past. Postmoderns, according to Latour, also accepted the modernistic abstractions as if they were real. In contrast, the nonmodern approach reestablished symmetry between science and technology on the one hand and society on the other.
I can understand the antimodern position. I can take a guess about the modern position and post modern position. However, the nonmodern approach is not clear to me at all. The symmetry between science and society? I understand he drew connections between the science and society (Laboratory Life I think?), but the contrasts between the above positions are not really clear to me.