Inspired by cp4space's blog about the geometry of self-replication:
http://cp4space.wordpress.com/2013/08/21/langtons-loops/ I've been obsessing about how, or in what sense, technologies are critters (not just memes) that replicate in the context of human beings.
There's a standard "biblical" self-replicating loop, where a physical book, dropped into an environment with sufficient literate humans, blank books and writing implements, can (accidentally) be read by a human and (perhaps) persuade the human that it would be a good idea to copy out the book (exactly) onto a new book.
A machine, such as a pump, can also self-replicate. At first I was thinking about a path involving a human disassembling the pump into parts, then using the parts as patterns in casting (perhaps sand casting) replacement parts. However, this cycle doesn't actually close - one generation might work well enough, but there is noise and shrinkage, which means that you can't keep doing it one generation after another into the future.
If the part had something like G-Code printed on it, then that could obviously close the loop. (This is recognizably a quine, like the virus protein shell and the data inside it.) The human could obey the G-Code on some standard set of machining equipment - perhaps if we're being low-tech for intuition-boosting, the G-code might instruct the human interpreter in a sequence of ruler and compass constructions, which, executed in wax or wood and then sand-cast, recreate the part. However, parts do not generally come with G-Code printed on them, or even schematics.
Schematics printed on the part would require competent machinists to be available in the context, but at least a schematic is digital.
Still, the dimensions of a part ARE visible - if you carefully measure a part that you have, and make some reasonable guesses, you can generally recover the (digital) schematic of the part. For example:
http://halfbakedmaker.org/?p=27122 This suggests a very geeky variant of telephone. The originator picks a irrational number with a formula, something like cos(1)*ln(Pi)^2. They compute it out to 8 digits or so (0.70801566) and add a little random noise to it. They send the noisy number to their neighbor, who puts it into something like the inverse symbolic calculator, and guesses which formula it is (balancing concerns like simplicity, aesthetics, and nearness to the number that they received). Then they compute it out, add noise to it, and send the number onward.
I think human beings must have a form of teleology sensors in our cognitive apparatus. Something about seeing the plan or mechanism behind an action, or even a device. It might be a combination of empathy and affordance sensors - the ability to see what you might be able to do with a thing.