What does O'Brien tell Winston about Goldstein's book ?

What Winston seems most shocked by is the fact that
O'Brien helped author the book. Then O'Brien futher tells Winston that the book is
essentially a bunch of nonsense. Obviously this is used repeatedly to capture people
like Winston and tell them the "truth"... or rather torture them to
it.

Here is what O'Brien specifically says about the
book:

The
programme it sets forth is nonsense. The secret accumulation of knowledge -- a gradual
spread of enlightenment -- ultimately a proletarian rebellion -- the overthrow of the
Party. You foresaw yourself that that was what it would say. It is all
nonsense.

Although O'Brien
glosses over a series of ideas about a potential rebellion, it is as if Winston is
learning that O'Brien knows what people will think, put it in there to pleasure them and
get them to believe in something just to be able to catch the thinkers and then "clean
them".