Yeah, Hedgehog's Dilemma refers to a theoretical scenario that goes something like this:
Sonic is the worlds fastest hedgehog. His nemesis Eggman throws both Amy and Tails off a cliff, and while they fall to their lava-drowning deaths, Sonic ponders if he has time to save them both. Being the worlds fastest hedgehog, of course he can, but while he was pondering this, both of his friends died. This means that what makes Sonic the fastest hedgehog in the world, is his stupidity.
It is later revealed that Tails only staged his death, and flew away to join Eggman while Sonic wasn't looking. ...because he's stupid.