First, I want to applaud Brooks for even travelling this ground, most folks seem happy to not even think about what they are up to for their four score and ten. Now to get snarky.
There are two kinds of people, those that divide groups into two groups, and those who don't ;-)
or my favorite, there are 10 kinds of people, those that understand binary and those who don't!
It is interesting to me that Brooks assigns Christensen, "the well planned life" and the "other" as the "summoned life". Supposedly, the person in the "summoned life" is always asking "what are my circumstances asking me to do?". Christensen is a Christian, part of what he does is ask God what his life is about. I'd argue that if one is determined to come up with two basic categories, the categories are life based on Transcendence (God, something bigger, philosophy, etc), or "Situational Ethics" ... what does it seem is the right thing for me to do today based on knowledge, experience, the environment, etc. So were I to label Brook's categories, they would be "Summoned" -- the God (or other transcendent) directed life, or "Situational" ... I'll make it up as I go along.
I'm not really a "two class" person ... I think "avoidance, distraction, ignorance and procrastination" are all more common categories for "how to live my life" than the ones that Brooks happened to pick out, but it is worth low cost of the quick skim anyway.