It still depends on their contribution right? If you said all lights are equal in strength, then being on top of one gives a strength of 1. Being x units away from it gives a some value less than 1, based on the sqrt of distance

Being close & between two lights would take the sum of their strengths, say .75 each so 1.5, giving a value greater than 1 (more light than either individually produces)

Being far from the two lights, each contributes .25 strength, so .5 total — half the light of standing on top of one

And of course if you get really far, a ridiculously large number of light sources are contributing a ridiculously small amount of light, which may still sum to something fairly small

I’m imagining it works like an influence map: https://www.gamedev.net/tutorials/programming/artificial-int...