The arch keystone got me thinking. What is a keystone and what makes it different to any other stone in the arch? Surely all the stones in the arch are needed to hold the structure in place. If any stone were to be removed the structure would collapse after all.
Most arch stones are precisely cut. Or at least we pretend they are precise. The keystone is different because it’s an oversized wedge that you slide in at the end to pick up the slack. You can’t cut it precisely because you don’t know how big it needs to be until it’s doing its job. Once in place though, you can trim it down to make it look like you knew what you were doing all along.
There’s a metaphor here, I think, for the style of “engineering” we see in software. It’s not a value judgement other than to acknowledge that, with software, it’s ok to be good enough and to iterate. Lots of real world engineering is like that, but keystones may be an exception.
Most arch stones are precisely cut. Or at least we pretend they are precise. The keystone is different because it’s an oversized wedge that you slide in at the end to pick up the slack. You can’t cut it precisely because you don’t know how big it needs to be until it’s doing its job. Once in place though, you can trim it down to make it look like you knew what you were doing all along.
There’s a metaphor here, I think, for the style of “engineering” we see in software. It’s not a value judgement other than to acknowledge that, with software, it’s ok to be good enough and to iterate. Lots of real world engineering is like that, but keystones may be an exception.