When I was young, the saying “according to one’s lights” always struck me as a silly expression.
The “lights” were the last things, bright red and closely adhering , that my mother removed in cleaning a fowl, the “liver and lights” always in combination.
It was not until some years later that I learned that “lights” is an old, a very old, term for “lungs.” In fact, it dates back to the twelfth century.
Our present phrase has nothing to do with that usage.
Here it is the light of knowledge that is meant; one’s opinions, information, abilities, capacities, or the like.