To solve this problem we would need to first understand the human mind, how it stores data, how it does computation, and how it interacts with names. So we would need the same set of information that we would need for creating AGI. A solution is probably only a couple of months/decades away.
Those aren’t formal definitions. “Formal” means, at the very least, that the specification is done in a formal language, and usually that conformance to the specification can be checked mechanically, that is, by a computer.