| 4099 | If Twins talking about 'water' and 'XYZ' have different thoughts but identical heads, then thoughts aren't in the head [Putnam, by Crane] |
| Full Idea: Putnam claims that the Twins have different thoughts even though their heads are the same, so their thoughts (about 'water' or 'XYZ') cannot be in their heads. | |
| From: report of Hilary Putnam (The Meaning of 'Meaning' [1975]) by Tim Crane - Elements of Mind 4.37 | |
| A reaction: Is Putnam guilty of a simple confusion of de re and de dicto reference? |
| 12026 | We say ice and steam are different forms of water, but not that they are different forms of H2O [Forbes,G on Putnam] |
| Full Idea: Putnam presumes it is correct to say that ice and steam are forms of water, rather than that ice, water and steam are three forms of H2O. If we allow the latter, then 'water is H2O' is not an identity, but elliptical for 'water is H2O in liquid state'. | |
| From: comment on Hilary Putnam (The Meaning of 'Meaning' [1975]) by Graeme Forbes - The Metaphysics of Modality 8.2 | |
| A reaction: This nice observation seems to reveal that the word 'water' is ambiguous. I presume the ambiguity preceded the discovery of its chemical construction. Shakespeare would have hesitated over whether to say 'water is ice'. Context would matter. |
| 3208 | Does 'water' mean a particular substance that was 'dubbed'? [Putnam, by Rey] |
| Full Idea: Putnam argued that "water" refers to H2O by virtue of causal chains extending from present use back to early dubbing uses of it that were in fact dubbings of the substance H2O (although, of course, the original users of the word didn't know this). | |
| From: report of Hilary Putnam (The Meaning of 'Meaning' [1975]) by Georges Rey - Contemporary Philosophy of Mind 9.2.1 | |
| A reaction: This is the basic idea of the Causal Theory of Reference. Nice conclusion: most of us don't know what we are talking about. Maybe the experts on H2O are also wrong... |
| 14200 | 'Water' on Twin Earth doesn't refer to water, but no mental difference can account for this [Putnam] |
| Full Idea: The word 'water' used on Twin Earth refers not to water but to this other liquid (XYZ). Yet there is no relevant difference in the mental state of Twin Earth speakers and speakers on Earth (in 1750) to account for this difference of reference. | |
| From: Hilary Putnam (Reason, Truth and History [1981], Ch.2) | |
| A reaction: In this world, if you and I separately meet twins, and I think about this twin while you think about that one, our mental states are different even if they are indistinguishable. I know I'm thinking about my twin, not yours. Indexicals. |
| 2343 | Reference may be different while mental representation is the same [Putnam] |
| Full Idea: The 'mental representations' of Earth speakers and Twin Earth speakers were not in any way different; the reference was different because the substances were different. Reference is fixed by the environment itself. | |
| From: Hilary Putnam (Representation and Reality [1988], §2 p.32) | |
| A reaction: There seems to be an elementary distinction here between what you think you are referring to, and what you are in fact referring to. "That man is the Prince of Wales" (pointing at the butler). |
| 6990 | Keep distinct the essential properties of water, and application conditions for the word 'water' [Jackson] |
| Full Idea: My guess is that objectors to the deflationary account of the Twin Earth parable are confusing the essential properties of water with the question of what is essential for being water. | |
| From: Frank Jackson (From Metaphysics to Ethics [1998], Ch.3) | |
| A reaction: That is, we must distinguish between the actual ontology of water's properties and the conditions under which we (in our society) apply the word 'water'. Interesting. The latter issue, though, might push us back towards internalism... |
| 3408 | Two identical brain states could have different contents in different worlds [Kim] |
| Full Idea: States that have the same intrinsic properties - the same neural/physical properties - may have different contents if they are embedded in different environments. | |
| From: Jaegwon Kim (Philosophy of Mind [1996], p.146) | |
| A reaction: This is a way of expressing externalism. It depends what you mean by 'contents'. I struggle to see how "H2O" could be the content of the word 'water' among ancient Greeks. |
| 3420 | Two types of water are irrelevant to accounts of behaviour [Kim] |
| Full Idea: The difference in the two types of 'water' in the Twin Earth experiment seem psychologically irrelevant, for behaviour causation or explanation. | |
| From: Jaegwon Kim (Philosophy of Mind [1996], p.203) | |
| A reaction: A rather important point. No matter how externalist you are about what content really is, people can only act on the internal aspects of it. |
| 15226 | What properties a thing must have to be a type of substance can be laid down a priori [Harré/Madden] |
| Full Idea: A statement which asserts that a substance or thing must manifest certain properties in order to be identified as a thing or substance of that sort can be laid down a priori. | |
| From: Harré,R./Madden,E.H. (Causal Powers [1975], 1.IV) | |
| A reaction: This observation is encountered in Sidelle, but this is earlier, and seems to be the key to the Twin Earth thing. It is just convention whether we call XYZ water, or whether there are two sorts of jade or one. Science has prestige. |
| 2437 | XYZ (Twin Earth 'water') is an impossibility [Fodor] |
| Full Idea: There isn't any XYZ, and there couldn't be any, and so we don't have to worry about it. | |
| From: Jerry A. Fodor (The Elm and the Expert [1993], §2.I) | |
| A reaction: Jadeite and Nephrite are real enough, which are virtually indistinguishable variants of jade. You just need Twin Jewellers instead of Twin Earths. We could build them, and employ twins to work there. |
| 12630 | If concept content is reference, then my Twin and I are referring to the same stuff [Fodor] |
| Full Idea: If the content of a concept is its reference, we can stop worrying about Twin Earth. If there are no senses, there is no question of whether my twin and I have the same WATER concept. Our WATER concepts aren't even coextensive. | |
| From: Jerry A. Fodor (LOT 2 [2008], Ch.1) | |
| A reaction: This seems like a neat solution. So do 'tap water' and 'holy water' have the same content to a Christian and non-Christian, when they co-refer to the contents of the font? |
| 17378 | Presumably molecular structure seems important because we never have the Twin Earth experience [Dupré] |
| Full Idea: It is surely the absence of experiences like the one Putnam describes that makes it reasonable to attach to molecular structure at least most of the importance that Putnam ascribes to it. | |
| From: John Dupré (The Disorder of Things [1993], 1) | |
| A reaction: That is, whenever we experience water-like stuff, it always turns out to have the same molecular structure. Twin Earth is a nice thought experiment, except that XZY is virtually inconceivable. |
| 4100 | The Twin Earth argument depends on reference being determined by content, which may be false. [Crane] |
| Full Idea: The Twin Earth argument does not refute internalism, since it depends on the 'Content-Determines-Reference' principle, which internalists can reject. | |
| From: Tim Crane (Elements of Mind [2001], 4.37) | |
| A reaction: The idea is that content should be understood in a context (e.g. on a particular planet). Indexicals count against a totally narrow view of content (Twins thinking 'I am here'). |
| 6633 | Twin Earth cases imply that even beliefs about kinds of stuff are indexical [Lowe] |
| Full Idea: The implication of considerations of Twin Earth cases is that even beliefs about the properties of kinds of stuff are implicitly indexical, or context-dependent, in character. | |
| From: E.J. Lowe (Introduction to the Philosophy of Mind [2000], Ch. 4) | |
| A reaction: This is a significant connection, between debates about the nature of indexicals (such as 'I' and 'this') and externalism about content generally. Is there no distinction between objective reference and contextual reference? |
| 3108 | If 'water' has narrow content, it refers to both H2O and XYZ [Segal] |
| Full Idea: My view is that the concepts of both the Earth person and the Twin Earth person refer to BOTH forms of diamonds or water (H2O and XYZ). | |
| From: Gabriel M.A. Segal (A Slim Book about Narrow Content [2000], 1.7) | |
| A reaction: Fair enough, though that seems to imply that my current concepts may actually refer to all sorts of items of which I am currently unaware. But that may be so. |
| 3110 | Humans are made of H2O, so 'twins' aren't actually feasible [Segal] |
| Full Idea: Humans are largely made of H2O, so there could be no twin on Twin Earth, and (as Kuhn noted) nothing with a significantly different structure from H2O could be macroscopically very like water (but topaz and citrine will do). | |
| From: Gabriel M.A. Segal (A Slim Book about Narrow Content [2000], 2.1) | |
| A reaction: A small point, but one that appeals to essentialists like me (see under Natural Theory/Laws of Nature). We can't learn much metaphysics from impossible examples. |
| 3124 | Externalists can't assume old words refer to modern natural kinds [Segal] |
| Full Idea: The question of what a pre-scientific term extends over is extremely difficult for a Putnam-style externalist to answer. …There seems no good reason to assume that they extend over natural kinds ('whale', 'cat', 'water'). | |
| From: Gabriel M.A. Segal (A Slim Book about Narrow Content [2000], 5.1) | |
| A reaction: The assumption seems to be that they used to extend over descriptions, and now they extend over essences, or expert references. This can't be right. They have never changed, but now contain fewer errors. |
| 15168 | That water is essentially H2O in some way concerns how we use 'water' [Sidelle] |
| Full Idea: If water is essentially H2O, this is going to have something to do with our intentions in using 'water'. | |
| From: Alan Sidelle (Necessity, Essence and Individuation [1989], Ch.1) | |
| A reaction: This very simple point looks to be correct, and raises very important questions about the whole Twin Earth thing. When new discoveries are made, words shift their meanings. We're not quite sure what 'jade' means any more. |
| 14706 | Your view of water depends on whether you start from the actual Earth or its counterfactual Twin [Schroeter] |
| Full Idea: Your verdicts about whether the stuff on Twin Earth counts as water depends on whether you think of Twin Earth as a hypothesis about your actual environment or as a purely counterfactual possibility. | |
| From: Laura Schroeter (Two-Dimensional Semantics [2010], 2.2.3) | |
| A reaction: This is the 'two-dimensional semantics' approach to the Twin Earth problem, which splits meaning into two components. Whether you start from the actual world or from Twin Earth, you will rigidly designate the local wet stuff as 'water'. |
| 17873 | Water must be related to water, just as tigers must be related to tigers [Almog] |
| Full Idea: It is a blindspot to say that to be a tiger one must come from tigers, but to be water one needn't come from water. ...The error lies in not appreciating that to be water one still must come from somewhere in the cosmos, indeed, from hydrogen and oxygen. | |
| From: Joseph Almog (Nature Without Essence [2010], 09) | |
| A reaction: A unified picture is indeed desirable, but a better solution is to say that the essence of a tiger is in its structure, not in its origins. There are many ways to produce an artefact. There could be many ways to produce a tiger. |