but it's an essence with two manifestations, right?

First, have a quote from Railsea

What, above all, about wood?

That is the key mystery. Wood makes trees trees. Wood is also what makes ties--those bars crosswise between railsea rails--ties. A thing can have only one essence. How can this, then, be?

Of all the philosophers' answers, three stand out as least unlikely.

--Wood & wood are, in fact, appearances not withstanding, different things.

--Trees are creations of the devil that delights in confusing us.

--Trees are the ghosts of ties, their gnarled & twisted & dreamlike echoes born when parts of the railsea are damaged & destroyed. Transubstantiated matter.

--China Miéville, Railsea, pp. 249-50.

Now, do you see my problem? I do love Railsea, and this quote is virtuoso storytelling fun, but I'm afraid Miéville has his logic mixed up here. If wood is the essence of trees, and wood is the essence of ties, then both those things have a single essence--namely, wood. It's an essence with two manifestations. To express this elegant confusion and not fall foul of logic, he could simply have said, "How could an essence like wood have two such different manifestations?" (but in more baroque, Railsea-esque language) and then gone on with his three great possibilities.

Still loving the story, though!

And now back to work.