[With apologies to Putnam, Pope, and all of you]

Two children are reading a text written by an AI:

The hobbits splashed water in each other's faces until they were both sopping wet

One child says to the other "Wow! After reading some text, the AI understands what water is!"

The second child says "It doesn't really understand."

The first child says "Sure it does! It understands that water is the sort of substance that splashes. It understands that people who are splashed with water get wet. What else is left to understand?"

The second child says "All it understands is relationships between words. None of the words connect to reality. It doesn't have any internal concept of what water looks like or how it feels to be wet. Only that the letters W-A-T-E-R, when appearing near the letters S-P-L-A-S-H bear a certain statistical relationship to the letters W-E-T."

The first child starts to cry.

Two chemists are watching the children argue with each other. The first chemist says "Wow! After seeing an AI, these kids can debate the nature of water!"

The second chemist says "Ironic, isn't it? After all, the children themselves don't understand what water is! Water is two hydrogen atoms plus one oxygen atom, and neither of them know!"

The first chemist answers "Come on. The child knows enough about water to say she understands it. She knows what it looks like. She knows what it tastes like. That's pretty much the basics of water."

The second chemist answers "Those are just relationships between pieces of sense-data. The child knows that (visual perception of clear shiny thing) = (tactile perception of cold wetness) = (gustatory perception of refreshingness). And she can predict statistical relationships, like that if she sees someone throw a bucket of (visual perception of clear shiny thing) at her, she will soon feel (tactile perception of cold miserable sopping wetness). She uses the word "water" as a concept-hook that links all of these relationships together and makes predicting the world much easier. But no matter how well she masters these facts, she can never connect them to H2O or any other real chemical facts about the world beyond mere sense-data."