Any discussion about knowledge or philosophy has to start with the nature of existence, or ontology. Latour's perspectives may seem anti-scientific at times, but they are absolutely not. By drawing attention to the limited scopes and purposes of logical inquiry and the scientific method, Latour paints a picture of man that is primarily shaped by essence: that we are communal animals evolved over time.
This means that all the philosophical cards are on the table, and as you might expect, Latour takes us all the way back to the original split of western thought—Plato himself. By analyzing Plato's hesitant opinions about objectivity (as in, is there even such a thing?) Latour reminds the culture of the West that modernity itself is a belief system of the same kind as those it sought to undermine.
That's complicated, but here it is again more simply, the dominant philosophy of the West has been oriented around science instead of mythology, and the claim of modernism is that culture has outgrown mythology. But if you view science for what it really is, then this conclusion must be unfounded, because those claims are outside the realm of scientific inquiry. In other words, they're built on belief.
These arguments are seriously important, because many citizens of the Western world would not agree with the blatant existentialism that has undergirded Western life. Many people do believe that life exists for a reason. That is outside the scope of Latour's arguments, but it is an important consideration regardless.
Basically, can we use scientific knowledge to change our nature? Latour says no. So if we can't belong to a new nature, we must be of the same kind as those humans who were purely religious, even if we are purely scientific. Latour's opinions culminate in his argument for a new framework to understand the story of progress in the West, and perhaps something more objective and holistic.
