timelets

All things, they say, undergo great changes, as one again succeeds another, and especially the art of divination; at one period it rises in esteem and is successful in its predictions, because manifest and genuine signs are sent forth from the Deity; and again, in another age, it is in small repute, being off-hand, for the most part, and seeking to grasp the future by means of faint and blind senses. Such, at any rate, was the tale told by the wisest of the Tuscans, who were thought to know much more about it than the rest.

https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Plutarch/Lives/Sulla*.html

Certain times are more predictable than others because of ... what?