Arcana Coelestia #486
486. Verse 4 And the days of Man after he beget Seth were eight hundred years; and he beget sons and daughters.
'Days' means periods of time and states in general. 'Years' means periods of time and states in particular. 'Sons and daughters' means the truths and goods that they perceived.
Jeremiah 10:12
12
He hath made the earth by his power, he hath established the world by his wisdom, and hath stretched out the heavens by his discretion.