The nature of things

April 14, 2011 12:57:56 AM CDT

So why does it take me so long to write about things? Because I have this awful tendency to ask questions like, "what is a doorknob?"

Seriously, finding a good answer to that question is like trying to nail jelly to a tree.

I imagine you're sitting there with a cocked eyebrow and a confused smile, thinking, "uh, it's that thing you use to open a door." Really? Like the remote control for a garage door?

Rethink: "You physically touch it to open the door." Really? Like the metal push-plate on a swinging door?

Rethink again: "it operates the latch mechanism." Really? Like the push bar on an emergency exit?

Losing patience now: "It's a roughly palm-sized object that can be attached to a 1/4" square steel bar, and when turned, operates the standard door latch." Really? Like a frozen potato?

We could play this game all day. Category-words are inherently sloppy because we apply them to a wide range of things. We choose a definition that applies reasonably well to all the items we want to include in the set, then ignore 90% of the things that fit the definition but weren't in the original set. That's one of the reasons why "full human AI is twenty years away," and has been for the last forty years.

That doesn't cut it when you're trying to make things. There's something awfully specific about a .993" x 2.001" x 4.628" bar of 1018 cold rolled steel.

The best framework I've found for discussing objects that can be made is a combination of "object as shape and material," and "object as function." That's still a long way from being an absolute definition for a category of things, but it does give you enough information to know whether you've built the right thing.