Monday, July 13, 2009

Against software "craftsmanship"

Lots of talk on web lately, esp from Object Mentor types like Uncle Bob and Michael Feathers, about the need for software developers to be more like craftsmen. This is true in small ways, I suppose, but it also seems false in large ones.

The decline of craftsmen, when possible, has usually been industrialization. One can get into frets about alienation of workers from their product, and in fact I usually agree or at least learn from such Marxist critiques. The moral core of those arguments, though, is the degree to which workers are left without meaningful tasks, in the aftermath of initial industrialization. That's a valid point when it applies, but it goes too far when you're just talking about how a software developer who's a dev today, and will be a dev tomorrow, should work.

So I don't think industrialization is evil or without useful lessons in this context. Mostly I think it's an important turning point in technical practices, a sort of coming of age. An inflection point, to use the modern parlance.

Back to software as craft: one of the revolutionaries of the Industrial Revolution was Eli Whitney, he of the interchangeable part. He famously figured out that an army could fight better if its rifles were each made from a finite number of said parts which could be carried into battle, pre-fabricated, rather than requiring a slew of blacksmiths and metallurgists to repair everything on demand. Or, more chronologically, he figured out that this was a better way to make a rifle, then he made a fortune selling rifles of that description to the U.S. Army, because the Army realized he was so, so right.

From interchangeable parts, computer scientists later borrowed the metaphor of subassemblies and, more broadly, decomposition. It's a natural enough idea mathematically, but making it intuitively clear to beginners almost always involves some example from the physical world--especially, the manufactured world.

From decomposition, we get the encapsulated object and the component. From these, we got to the unit test.

Would the craftsman have invented the unit test? To me, the answer is tautologically no. To break a task into subsitutable, commodity parts is, by definition, anti-craft. It is industrial. It is engineering. It's applying arguments (or motivation) of scale; ideas of aggregate, statistical value; perspective at the macro, systemic level; appreciate for complexity, emergent behavior, and the like. By definition, craft appreciates fuzzy essences, "things in themselves," metaphysics rather than physics. Those essences, those things, those human endeavors are valuable, but they are not engineering. I'd argue that the products they produce are not reliable in the way that an industrial product is, and therefore, that software developers should not be craftsmen.

Software needs ideas from the 21st century; the 19th already played out, and the craftsmen lost.

Postscript: Is it me, or is Uncle Bob's software advice, at least as it involves the community of developers (as opposed to pure technical practices like SOLID) getting progressively more hidebound, verging on counterrevolutionary and possibly trending toward stupid?

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