Startup founder to VC: We're going to build an AI that can do X!

1 billion dollars later: We discovered we can't do X because there's this thing called "undecidability."

Undecidability puts fundamental limits on what we can do with computers. You can't even do simple things like write a program which can { determine if two programs are equal, determine if two programs would have equal outputs given any input, if any program will return a "1", if any program would halt, ... }

This feels kinda important considering what people might try to build using AI.