  The James Webb Space Telescope (JWST) has revealed extremely distant galaxies
at unprecedentedly early cosmic epochs from its deep imaging using the
technique of photometric redshift estimation, with its subsequent spectroscopy
confirming their redshifts unambiguously, demonstrating the ability of JWST to
probe the earliest galaxies, one of its major scientific goals. However, as
larger samples continue to be followed up spectroscopically, it has become
apparent that nearly all photometric redshifts at these epochs are biased high
with confidence >>99%, for as yet unclear reasons. Here we show that this is
the same statistical effect that was predicted in different contexts by Sir
Arthur Eddington in 1913, in that there exist more lower redshift galaxies to
be scattered upwards than the reverse. The bias depends on the shape of the
intrinsic redshift distribution, but as an approximate heuristic, all
ultra-high photometric redshift estimates must be corrected downwards by up to
one standard deviation.
