Winston begins to read Goldstein’s book, the first chapter is :Ignorance is Strength.
In simple terms it described the classes of society. Despite the different terms varying from age to age the facts were the same…”the essential structure of society has never altered…after… seemingly irrevocable changes, the same pattern has always reasserted itself…”
Winston, as the reader stops, and considers the truth of what he has read.
What he reads is a truth we ‘know’, have experienced or learned.