It sounds like Kaku is a learned, educated man. He does have a professorship at a well known university. Also, if I recall correctly, black holes are still theoretical but they get talked about all the time as the launching point for derivative ideas.
I'm reading a book right now called The Theory of Nothing, by theoretical physicist Russell K. Standish, that makes the claim that black holes may be incubators of new universes.
Anyhoot, in reply to the Gospel of John 1:1, Standish says,
In the beginning there was Nothing, not even a beginning! From out of this Nothing, emerged everything we see around us today.A rather startling claim IMHO. It looks like Professor Kaku might dispute this claim. But I have no details of Kaku's argument....