There’s a kind of knowledge that involves:

• finding things quickly
• decades of built-up knowledge
• “what feels right to come next” being a key question

One example: DJs. Imagine a DJ just spinning what feels good. A track is coming to an end. The DJ must come up with a next track to play that not only matches the BPM well enough, but most importantly, feels right. They may have thousands of records, but they can search that out. I bet every song they play, they know it well enough to hum it pretty accurately.

Another example: cooks. Cooking involves knowing enough things you can make that you can pick one out that uses what you have, matches everyone’s food requirements, and fits everyone’s tastes and mood.

(A third example might be improvisers, both musical and comedic. But I’ll focus on DJs so I don’t have to repeat everything 3 times.)

How do they/we do it? I’m probably a crap DJ, but I’ve had the experience of “I know what we should hear next” and it felt pretty right. There was no explicit “data structure” in my mind - I wasn’t saying “ok this sounds kinda new-disco, now we need a classic-disco song to come next, let’s sort by BPM, ok that one”, I just thought “oh yeah this would sound good.” (Indeed, when I try to data-structure it, it gets worse!)

Part of it has to be years of practice - I’ve got a wider music vocabulary than some, because I make more than zero effort to seek it out, but real professional DJs' vocabularies must be much wider!

But that doesn’t really answer the question of “what’s going on in those years of practice.”

why

Yes, of course behind this inquiry is an Angle: what if we can at least partially speedrun this??

Before you get all mad at me for optimizing everything! I would love to speedrun mental music storage because DJing is fun. Even just for yourself. But it feels so opaque and impossible because I only have, idk, 3k songs I know well enough to DJ.¹ So if I could boost that to 10k in less than, say, 4 more decades, that would be nice.

It would also be fun to write a cookbook with this in mind, one that answers the actual hard questions of: 1. what do I buy, 2. what do I cook. Without getting too stiff about either one. Because “here’s a list of recipes” sure isn’t it - but every time I try to think about “what is it, then?” my head explodes with all the things you have to keep in mind to cook reasonably.