they gained control of an obedient and potentially limitless force.
Is fire really “obedient” and “limitless”?
I understand what he’s saying—that by learning to creat and to an extent, control, fire, we were exerting a far greater amount of control over our environment and ecosystem than we ever could, and this control is what allows us to change our environment to suit our lifestyle, rather than the other way around. But I wouldn’t say fire is an “obedient” force so much as we made it tame-able.