Please help me understand these two sentences.

Relph is aware of links between* the landscape idea, the evolution of scientific method and renaissance humanism. But in seeking to couple humanism with Cartesian science *as pure intellectual categories revealing themselves in alienated or placeless landscapes, Relph rejects one side of the dialectic between thought and action in the real historical world.

1. I couldn't figure out which two words are connected with between* . Because I was told *between only can be used between two words. but there are three phrases after "between".

2. I couldn't figure out what the phrase "as pure intellectual categories" refers to. Does it refer to Cartesian science? Or "couple humanism with Cartesian science" ? Or is the whole phrase a Adverbial clause?

3. "revealing themselves". I couldn't figure out what "themselves" refers to.

I am sorry for so many questions, I completely lost in these sentences:(

Thanks a lot!