Describing a defeat in vivid detail is rehearsal, and a rehearsed defeat gets lived out by an entire generation.
Measurements make a forecast operational, which is why a report of heights and walls did to those men what a promise would have done if held with equal precision: the picture set the state, the state produced the melting, the melting produced refusal, and refusal compounded into forty years of circles.
They already believed, without evidence, in a future nobody had walked; they simply believed in the giants. A mind that can build cities fortified to the sky out of hearsay is fully equipped to believe a way through. Left unturned, a person spends a lifetime adjacent to what was promised, close enough to describe it in detail and never once standing in it.