Constructive criticism please: In 1975, Hillary Putnam published a paper entitled “The Meaning of ‘Meaning’”, in which he proposed an interesting “thought experiment” (see Putnam, H; “The Meaning of 'Meaning'” In Philosophical Papers, Vol. 2: Mind, Language and Reality. Cambridge University Press (1975)). He begins by supposing that elsewhere in the universe there is a planet exactly like earth in virtually all respects, which we refer to as ‘Twin Earth’. On Twin Earth there is a Twin equivalent of every person and thing here on Earth. The one difference between the two planets is that there is no water (ie no H2O) on Twin Earth. In its place there is a liquid that is superficially identical, but is chemically different, being composed not of H2O, but rather of some more complicated formula which we abbreviate as ‘XYZ’. The Twin Earthlings who refer to their language as ‘English’ call XYZ ‘water’. Finally, we set the date of our thought experiment to be several centuries ago, when the residents of Earth and Twin Earth would have no means of knowing that the liquids they called ‘water’ were H2O and XYZ respectively. The experience of people on Earth with water, and that of those on Twin Earth with XYZ would be identical. Now Putnam poses the question: When an earthling, say Oscar, and his twin on Twin Earth say 'water' do they mean the same thing? According to Putnam, although Oscar and Twin Oscar are in the same physical mental states (i.e., mental states interpreted in a physicalist way), Oscar points at and therefore means H2O, whereas Twin Oscar points at and therefore means XYZ. Nothing in their heads would "tell" us the difference, that is, allow us to distinguish between these two different meanings. Therefore meanings are not in the head. Instead, we rely and depend on the world to give and assign meanings. From this, Putnam concludes that “meanings just ain’t in the head”. The fallacy in Putnam’s argument lies in the fact that he confuses two different epistemic perspectives (one perspective which is the one of the less privileged actors Oscar and Twin Oscar on the stage, who know nothing about H2O or XYZ but know only “water”; the other perspective, the more “privileged” perspective, is the one of the stage manager, who knows that some actors have access to H2O, whereas some have access to XYZ), and he assumes that the “meaning” embodied within one perspective must equate precisely to the “meaning” embodied within the other perspective. Meaning derives from understanding and knowledge. If I understand that water comes in two “types” (H2O and XYZ) then of course I must distinguish these two types within my semantics if I am to avoid confusion in meaning. This is the perspective of the privileged observer. However, if I understand only that water is a colourless, odourless, tasteless liquid which at times falls from the sky (and I have no knowledge of the fact that water is either H2O or XYZ), then my “meaning” when I talk of “water” does not embody this difference in types of water, my “meaning” does not distinguish between these two types. This is the perspective (the meaning) of the less privileged observer. In short – if my knowledge and understanding differ from yours, then it is quite possible that the meanings I ascribe to certain words (my semantics) are also different to the meanings you ascribe to the same words (your semantics). It is a mistake, therefore, to assume (as Putnam seems to want to do) that there is some unique “meaning” within words (unique semantics) which is not dependent on subjective knowledge and understanding. When Oscar points at H2O and says “water”, he has no idea that he is pointing to H2O. He knows, and when he utters “water” he means, simply “that colourless, odourless, tasteless liquid which at times falls from the sky”. Similarly, when Twin Oscar points at XYZ and says “water”, he has no idea that he is pointing to XYZ. He knows, and when he utters “water” he means, simply “that colourless, odourless, tasteless liquid which at times falls from the sky”. To Oscar and Twin Oscar, the word “water” means the same thing. Putnam cannot understand this, because he seems to believe there is some underlying absolute semantics which is independent of observer perspective, and he insists on confusing his privileged perspective (his knowledge and understanding that water comes as both H2O and as XYZ) with the more limited perspectives of Oscar and Twin Oscar. Once the relative nature of our epistemology is accepted, the problem is solved, and meanings are once again firmly rooted where they belong - in the head.