To give you an flavor of the book, it is like his earlier book Encouraging Words. He has organized the chapters to be one one paragraph long but there are 200 of them.
Anyways, today he hits on intimacy. It is your practice he says. It is your realization he says. How do this hit you?
Intimacy is just the practice and realization of Zen. Where have we heard this before?
Robert introduces us to a metaphor involving an abstract branch of mathematics. He uses a term new to me, "coterminal". I looked it up and was pleasantly surprised by the geekiness of the term.
In category theory, an abstract branch of mathematics, an initial object of a category C is an object I in C such that for every object X in C, there exists precisely one morphism I → X.... Initial objects are also called coterminal, and terminal objects are also called final.
If an object is both initial and terminal, it is called a zero object or null object.
Initial objects are called coterminal and terminal ones are called final. Robert is pointing out that intimacy is not and initial state that becomes something else. It is the field of practice and realization.