The book suggests that Zen presents an alternative to Hegel's most famous bit, the master-slave dialectic, in which human thought and activity is presented as foundationally a struggle for dominance. Instead, Zen cultivates an attitude of friendliness, a radically different stance. The master/slave stuff is part of the Western character, an aspect of its interiority. Zen by contrast de-emphasizes interiority in favor of relationship and openness.
Satori is the other of selfhood, the other of inwardness, but it is not an outwardness or alienation. Rather, it involves the overcoming of the distinction between 'inward' and 'outward'. Spirit de-internalizes itself in an indifference, even in friendliness. (p47)
He contrasts it with the master-slave dialectic of Hegel. In MS, two minds encounter one another and fight to be The Mind, more or less (my understanding of Hegel is cartoonish at best). This is demanded by Western interiority. In Zen, there is no interior, just openness and relationship, permitting a different kind of stance.