A good subject on which we can test this concept is sugar. Recently, advances in chemistry have allowed us to create sugar molecules which are the inverse of regular molecules. They taste more-or-less like sugar, but the body doesn't recognize them as sugar, and so doens't obtain nutrition from them. Do we call this alternative molecular formula [sugar] or do we call it something else, like [sugar substitute].Metaman wrote:We identified water originally by its characteristic feel, appearance and perhaps taste." And that "If there were a substance, even actually, which had a completely different atomic structure from that of water, but resembled water in these respects, would we say that some water wasn't H20?
I think the most important thing to understand (for this discussion) is that WORDS are generally context sensitive. When a house wife tells her kid to get a drink of water, she may well be talking about something different from the scientist who is discussiong the properties of water/H2O. In common, everyday speech, the definition of water includes the notion that it usually has some impurities in it. So the fact that [water] is not identical to H2O is accounted for by the definition that is appropriate for the given context.
That's why when you go to the store, and buy less tained H2O it's not called water--it's called purified water or distilled water. We have to distinguish pure H2O from tap water, but it is the tap water that retains the most fundamental name WATER.
Given this, we can reexamine the contents of a [cup of tea]. The definition of tea is a flavoring substance that is steeped in hot water. So the fact that Tea contains water is accounted for by the definition of TEA. If we're expecting a cup of tea, then it makes no sense to discribe it as tained (or impure) water. On the other hand, if we're expecting water and we're handed a cup of tea, then it would make perfect sense to say something like, "This water is bad."
Because we are defining our drink in the context of water, it makes sense to describe the drink in terms of the taint (or impurity) that is in the water.
For the first example you gave, "Water is life" ... what's going on here is that we are using a sense of [is] that does not indicate equivalence. We are not saying that water is the same thing as live. We are saying that water is one of the characteristics (or requirements) of life. Thus, it is not accurate to suggest that this "water" doesn't contain H2O as surely as example (2) and (3). It's just that we are using the word in a different way.
Thus, I would argue that none of your examples are referential failures. This, however, doesn't mean I think Kripke is right, at least not as you've explained his view.