The significance of a Galois extension is that it has a Galois group and obeys the fundamental theorem of Galois theory.

One of his favorite metaphors for the historian, drawn from the Preface to Hegel's Philosophy of Right, likens hu to the owl of Minerva, whose flight at dusk provided the setting for mature reflection on the day that had passed.

[…] The old man with the look of one Drowning, who gave thy freedom unto thee— ’Tis he still breathing, still unwhelmed, who crosses Thy path once more to-day.

I was in San Francisco just the other day.