[talldayo]

I would assume it's a statement on determinism. The phrase is based on the dual usage of "just" in meaning "simply" the first time, and then "rationally" in the next. It seems the author wants you to refuse the simple understanding of things and focus on the causal chain-of-events leading up to them instead.

That's just my interpretation, though. "Just" is also commonly used as a term for religious righteousness, which could also change the meaning. I'm unfamiliar with Jim Rohn too, if that helps :P