Think of it like this: Chomsky was testing the brain's language parser by handing it weird things and seeing how it reacts. Like you might do with a new programming language: what happens if I try to add strings, or divide them? Is zero true? Is the string "nil" true? Is == different from ===? Can I pass a function into a function?<p>The brain's language center is undocumented, so we try throwing potential sentences at it and see what works or doesn't, then try to reverse engineer what it's doing. The buffalo sentence conforms to the rules we know about word order, and can be logically explained, but somehow it fails. Finding out why is part of the reverse engineering process.