What is the origin of "see things in a different light" or "see things in a new light"?

Solution 1:

Figurative usage of "light" in that respect dates well before electricity. Light, on the other hand, has always existed. Early usage instances appear to draw on the religious metaphor of Light:

Meaning "a consideration which puts something in a certain view" (as in in light of) is from 1680s.

(Etymonline)

Early usage instances:

Religious Library, Volume 1 American Tract Society, 1671

• A new light, in which things appear far otherwise than they did before.

The Trials of Sir. Geroge Wakeman 1709:

• For the consideration is not, how it now appears to you or to me, who look upon it in a different Light, and on contrary Principles from theirs

Solution 2:

Interesting question! I did a Google Ngram search and found a reference to

Papers of the Governors: 1681-1747 - Page 619

Pennsylvania. Governor, ‎George Edward Reed - 1681 - ‎Snippet view - ‎More editions

Your extraordinary manner of stating the Case would indeed set everything in a different Light; but while you can call your sending up about three hundred armed Men with Drum and Trumpet to terrify our Inhabitants by the name of levying of ...