Why are moths and other insects attracted to light?

(WHTM) -- Picture yourself outside enjoying a summer evening on your patio. String lights are all around you as you enjoy the beautiful weather.
Then as soon as you turn those lights on, you start to see a swarm of bugs that makes you want to go back inside the house.
So, why does this happen? Why do bugs love to swarm any sort of light source?
The Farmer's Almanac says it has something to do with bugs being positively phototactic. That is a fancy way of saying the bugs instinctively move toward