In this chapter (ch. 4) Brooks is arguing that people have different sets of moral foundations. So here, he suggests that we find common ground in moral groundings we do share and work back from there.

So, we agree that people have value and should be cared for, that's the why. The what is the things that we do, the policies we put in place, the people we elect that help us address the why.

I think it's an intriguing argument, though I was yelling at the dark air of the outdoor space I was sitting in for most of the rest of the chapter. But that's for another time.