I recently read a book that many times made me look at my watch and then grumble. The book in question was
The Long Earth by Terry Pratchett and Stephen Baxter. The basic premise of the book is that it suddenly became easy to transport yourself between parallel Earths. The one key caveat to this transfer was that metallic Iron would not transfer over with you. Obviously organically bound Iron would transfer over or you wouldn’t live but the hard shiny stuff just got dropped behind. A big chunk of the world building of this book was based on that. The implication being that technology levels for people transferring over to a parallel earth would be very low. There is a scene where somebody is trying to bury bodies with a wooden shovel. The crippling effect of not having iron was mentioned in many places and in a variety of explicit and implied ways. It is fundamental to the book.
So why did looking at my watch make me grumble? Because the case and strap of my watch are made of Titanium. It isn’t even a particularly expensive watch. Iron may be very common to the point of ubiquity in our technology, but there are plenty of alternatives – Aluminium. Carbon fibre, ceramics, Titanium, Magnesium* and so forth. Generally speaking there are actually superior alternatives to Iron/Steel for pretty much any role you care to mention. Sure they are more expensive, but they do exist. What is more, given a few years of development after the discovery of parallel Earths (as the book suggests), you can expect industry to have come up with a whole range of non-iron tools – particularly
firearms - the lack of which was particularly noted in the book.
So what bugged me was that alternatives to Iron were not addressed by the book. Not even a line to discount the impact of other materials as being too expensive. That wouldn’t necessarily be valid but at least it would show the authors recognised the situation and were trying to address it. Instead it looked as if they had found their macguffin to create low technology and were sticking with it. It just seemed sloppy and every time I struck it, it pulled me out of the story.
I think it bugged me more because the book is clearly Science Fiction. I may not have held a fantasy world building up to quite the same standards - or perhaps not. Whatever, I’m sure the readers here who run world building courses will be saying "see – I told you so".
*Magnesium alloy as used in car wheels actually has a standard that says no more than .005% of the alloy can be Iron or it affects the corrosion resistance. In the scenario of the Long Earth I can see an industry of carrying rims across to a parallel Earth and back again to remove all the unwanted Iron from the alloy wheels.