The Social Network star reveals he went back to basics to get into the mindset of his cold-blooded eco-activist character, who plots with co-stars Dakota Fanning and Peter Sarsgaard to blow up an Oregon dam as part of a protest against the deterioration of the land.
Speaking at the Venice Film Festival in Italy, he told reporters, "It just gives you a different sense of living. When you are planting the food that you eat, you feel a direct sense with interacting with the world for practical reasons, and alternatively you are feeling disgusted by a lot of modernity just by being separate from it. That is what my character believes in.
"My character thinks of himself as a soldier in a war fighting what he views as modern society that's been co-opted by business and technology.
"I suppose there is a kind of irony if he is fighting to create a more beautiful, peaceful and sustainable environment, but doing it through kind of dangerous means. He views his acts as right and just, and he views the damage as collateral damage."