Abstract
The Chomskian holds that the grammars that linguists produce are about human psycholinguistic structures, i.e. our mastery of a grammar, our linguistic competence. But if we encountered Martians whose psycho-linguistic processes differed from ours, but who nevertheless produced sentences that are extensionally equivalent to the set of sentences in our English and shared our judgements on the grammaticality of various English sentences, then we would count them as being competent in English. A grammar of English is about what the Martians and we share. In this note, I argue that a recent attack on the Martian Argument by Laurence fails to mitigate its force.