Big Brian is a clever guy with a good understanding of light bulbs.
Brian turns on the first light switch, but he doesn't quite have the energy yet to climb the stairs. So he waits a minute or two. He then turns off the first light switch, turns on the second light switch, and then summons all his energy and climbs the stairs. The upstairs light that is on is obviously connected the 2nd light switch. He touches the two upstairs lights that are turned off. Big Brian cleverly deduces that the one that is hot to touch is connected to the first light switch (it was just on for a minute or two) , and the one that that's cold to touch is connected to the third switch.
The key to this one is that a light bulb can have 3 states (on, off-cold, off-hot). With only 2 states (on, off), the problem would be impossible. Way to go Big Bri!
