How did Dostoevsky say you destroy a prisoner psychologically?

... and how does it relate to white-collar work?

From here:

As Dostoevsky said somewhere: if you want to totally destroy a prisoner psychologically, just make them dig a hole and fill it in again, over and over, all day long - and in some gulags, they actually tried that out as a form of torture and he was right, it worked. It drove people completely crazy.

David Graeber

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