"Cogito ergo sum" - I think therefore I am (Descartes)

Some things are simple and obvious when you are a rational and smart pony like Twilight Sparkle. But when you try to make a crazy mare like Pinkie Pie obey the rules of logic, you should expect at least some challenge.

But that's not a story about logic. It was supposed to be, but it isn't. Or at least not anymore. I think it's just a story about two friends spending some time together...