The first philosophical problem we will tackle is known as the problem of material constitution. The online Stanford Encyclopedia of Philosophy contains a wealth of information on all sorts of interesting philosophical problems, so expect to see it linked a lot in this section. Its article on material constitution is well worth reading: http://plato.stanford.edu/entries/material-constitution/
The problem of material constitution can be demonstrated in a few different ways: one of my favourites is the story of the Ship of Theseus. In this story, the famous wooden Ship of Theseus is preserved in a museum. Over time, its boards wear out and are replaced until eventually not a single original board remains in the ship. Is it still the Ship of Theseus?
Taking the problem a step further, suppose someone has been collecting the worn-out boards, and when all the boards have been replaced, they construct a (substantially worn-down) ship out of the original boards. We now have two complete ships, both of which have some claim to the original identity of the Ship of Theseus. Which is the real one?
Skimming the Stanford entry, there are two popular solutions which seem to somehow fit within the framework I’ve layed out so far: Unger’s Eliminativism (section 4), and Carnap’s Deflationism (section 7). In effect, my solution is a synthesis of these two approaches.
Recall for a moment my third axiom: “There is some underlying consistent reality that is made up of things”. Also note the scientific reality of molecules and atoms etc. My fundamental claim follows naturally from these and is quite similar to Unger’s: properly speaking there is no such thing as a ship, there is only some collection of things in the underlying reality (the correct word is “atoms”, but it’s already been used for something else by physics!) that are arranged in a pattern we think of as a ship. To quote the Stanford article, “the most common reaction to this claim is an incredulous stare”, and here is where I am able to draw on Carnap’s Deflationism and my own work to go beyond Unger and provide a coherent answer.
When you say “but of course there are such things as ships” and I say “there is no such thing as a ship”, strictly speaking we are both right — we are using different meanings of the word is. The problem, as Carnap would argue, is only linguistic.
For this to make sense, recall way back to my post on Truth and Knowledge. We have now covered enough to realize that what I originally referred to as “Relative Truth” is nothing more than the set of abstractions we work with in our day-to-day life. Using these tools, we can see that when you say “but of course there are such things as ships” you are referring to the abstraction of a ship, the relative truth of the fact. The “ship” abstraction is one we both presumably share, so I am happy to grant your claim. However, when I say “there is no such thing as a ship” I am referring to the fundamental being of a ship, the absolute truth of the fact. Since ships are made up of molecules and atoms, there is no such thing that is, in itself, the ship, and so my claim is also correct.
To conclude, both Unger and Carnap were right, as far as it went; they each simply missed half the picture. In the Ship of Theseus, there is no conflict about what happens to the underlying reality (whether it consists of particles or something more exotic). The only question lies in what we call the resulting abstractions, and this is an issue because here there is no absolute truth to refer to; they are only abstractions, and abstractions are perpetually subject to the process of social negotiation.