Denunciation as a Test of Loyalty

From The Invisible Writing, by Arthur Koestler (PFD Books, 2015), Kindle Loc. 1685-1693:

There is one aspect of time-travel in which science-fiction writers have never been interested, and which for a while interested me to the point of obsession. If a time-machine could be made, it would be possible to undo what one has done in the past.

Denunciation is an elementary duty of every Party member, and a test of his loyalty. During the Purges, women denounced their husbands, and boys were made to sign public statements demanding that their fathers be hanged. Denunciation is a scientifically fostered epidemic, the Party's principal method of waging germ-warfare against the human spirit.

During my seven years in the Communist Party, the only person whom I denounced or betrayed was Nadeshda, and she was the person dearer to me than anybody during those seven years. It is no exaggeration when I say that I would have died for her readily and with a glow of joy. The Party to which I betrayed her I did not love; I had qualms and doubts about it, and moments of exasperation. But I was part of it, as my hands and my guts were part of myself. It was not a relationship; it was an identity.