 Suppose you say, or write, the sentence, “Water is wet”. Your twin produces a sentence with the same phonetic or syntactic form: “Water is wet”. Do the two sentence-tokens have the same meaning? Putnam’s answer is that they do not. This answer will be found inviting by anyone who thinks of meaning as a matter of reference, or truth-makers, or truth-conditions, or, in short, anyone who thinks that the meaning of a term or sentence is, at least in part, a matter of its relation to some kind of worldly correlate. The reference of the syntactic/phonetic form “water” differs between you and your twin. When you utter the sentence, you are making a report about water—a substance composed of hydrogen and oxygen. But your twin’s corresponding report is about the substance on twin earth. For purposes of identification, we can call this substance twater, but the twin earthlings, of course, call it no such thing. They speak twin-English, and so refer to this substance with the syntactic/phonetic form “water”. Moreover, your utterance and your twin’s utterance are both true, but different facts make them true. Your utterance is made true by a fact about water, whereas your twin’s utterance is made true by a fact about twater. The truth-conditions of the utterances also differ. For your utterance to be true, water must be wet. For your twin’s utterances to be true, twater must be wet. Thus, from the perspective of theories that think of meaning in terms of these kinds of worldly correlates—reference, truth-makers, truth-conditions—there are good reasons for endorsing Putnam’s conclusion.