On software engineering hermeneutics

When I use a word it means just what I choose it to mean — neither more nor less.

Humpty-Dumpty in Alice through the Looking Glass

In my recent round of TDD clarifications, one surprising experience is that folks out there don’t agree on the definition of TDD. I made it as clear as possible in my book. I thought it was clear. Nope. My bad.

Kent Beck in Canon TDD

I invented the term Object-Oriented, and I can tell you I did not have C++ in mind.

Alan Kay in The Computer Revolution Hasn’t Happened Yet

I could provide many other examples, where a term was introduced to the software engineering state of the art meaning one thing, and ended up meaning “programming as it’s currently done, but with this small change that’s a readily-observable property of what the person who introduced the term described”. Off the cuff: “continuous integration” to mean “running automated checks on VCS branches”; “Devops” to mean “hiring Devops people”; “refactoring” to mean “editing”; “software engineering” to mean “programming”.

I could also provide examples where the dilution of the idea was accompanied by a dilution of the phrasing. Again, just typing the first ideas that come into my head: Free Software -> Open Source -> Source Available; various 1990s lightweight methodologies -> Agile Software Development -> Agile.

Researchers of institutions and their structures give us tools that help understand what’s happening here. It isn’t that software engineers are particularly bad at understanding new ideas. It’s that software engineering organisations are set up to reproduce the ceremonies of software engineering, not to be efficient at producing software.

For an institution to thrive, it needs to be legitimate: that is, following the logic that the institution proposes needs to be a good choice out of the available choices. Being the rationally most effective or most efficient choice is one legitimising factor. So is being the thing that everybody else does; after all, it works for them, so why not for us? So is being the thing that we already do; after all, it got us this far, so why not further?

With these factors of legitimacy in mind, it’s easy to see how the above shifts in meaning can occur. Let’s take the TDD example. Canon TDD says to write a list of test scenarios; turn one item into a runnable test; change the code to make that test and all previous tests pass; optionally refactor to improve the design; then iterate from the second step.

First person comes along, and has heard that maybe TDD is more effective (rational legitimacy). They decide to try it, but their team has heard “working software over comprehensive documentation” so they don’t want to embarrass themselves by writing a list of test scenarios (cognitive legitimacy). So they skip that step. They create a runnable test; change the code to make that test pass; optionally refactor. That works well! They share this workflow under the name TDD (Red-Green-Refactor).

Second person comes along, and has heard that the cool kids (Kent Beck and first person) are doing TDD, so they should probably do it too (normative legitimacy). They decide to try it, but they notice that if they write the code they want, then write the tests they want, they end up in the same place (they have code, and they have tests, and the tests pass) that Canon TDD and TDD (Red-Green-Refactor) end up in. So where’s the harm? Now they’re doing TDD too! They show their colleagues how easy it is.

Now everybody is doing a slightly different TDD, but it’s all TDD. Their descriptions of what they do construct the reality in which they’re doing TDD, which is an example of what the researchers call performative discourse. TDD itself has become ceremonial; the first and subsequent people are doing whatever they want to do and declaring it TDD because the legitimate thing to do is called TDD.

This does give those people who want to change software engineering some pointers on how to do it. Firstly, overshoot, because everybody’s going to meet you a short way along the path. Secondly, don’t only talk up the benefits of your proposed change, but the similarities with what people already do, to reduce the size of the gap. Thirdly, make sure that the likely partial adoptions of the change are improvements over the status quo ante. Fourthly, don’t get too attached to the words you use and your choice of their meanings: they mean just what anybody chooses them to mean—no more and no less.

About Graham

I make it faster and easier for you to create high-quality code.
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