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 gnar...