the case for definitions

Seems like these days, the only time I write a blog post is when I'm responding to one of Lu's blog posts*.

Anyway, she's just written a nice one about, well, I mean it starts being about live coding but then it gets kind of surreal. Ok ok it's also about definitions. Lu is... I think it's fair to say they're not a fan:

I hate definitions. I absolutely hate them. They drive me crazy.

I refuse to do them! Or I do them as little as possible! Or I do a when-based definition instead, which is a cop out.

And, you know what - I like Lu's post a lot but I disagree with them here. I like definitions! I think it's good to try to define things!

Lu has anticipated this response:

People tell me they like what I say about definitions but then they also disagree with me.

Okay, Lu, what's your problem with them?

I don’t know if you’ve noticed this but the world is a big big sloppy sloppy mess. We try to make sense of it by not seeing it that way, but instead see it as being made up of discrete things, like cat and man and woman, and it doesn’t work.

Or maybe it works for 98% of cases but it doesn’t work for the remaining 2%. And so what we do is we add all sorts of asterisks and exceptions to our definitions to account for the 2%. And I think that’s terrible, because for me: The 2% of exception cases to any definition are the MOST INTERESTING PART but they end up being an afterthought.

Those 2% of cases reveal the truth of the world to us: They show us what we— that we are just sloppy sloppy slodge made of bazillions of tinier pieces of slodge and therefore the gaps between us / me and you are only an illusion

To which I say: yeah! exactly! The point of making a definition, for me, is: to help find the interesting 2%. It's to see where the definition breaks down. It's to find the weird edge cases.

Maybe it's just me? I know I can sometimes be a little perverse, a little deliberately awkward. Someone says something with a confident tone and I'll start looking for the contradictions and exceptions. And I like the contradictions and exceptions. And sometimes the ones I'll come up with are interesting or are unsure or are under-explored. It's a rich seam to explore! But I wouldn't have found that seam without the confident statement I tried to contradict. And once you realise this, you realise that sometimes you have to be the one to make the confident statement.

And yeah fine, maybe a definition is helpful to reach a shared understanding. We could be talking about many things, but here's the one we're actually talking about. Let's get on the same page. Maybe a definition can help with that. It's a useful tool for that – but it's not the best one, generally people understand things better with some examples and some context.

But! the act of trying to define something makes you reach for the places where stuff breaks down. And this means that your definition is always going to be wrong and incomplete. That's fine. Don't try to pretend that your definition is ever going to be complete and, well, definitive. Better to make one, share it around, break it, maybe do without for a bit. Be slippy about it.

[* this is a joke]