GRAVITY SIXTEEN -- Thursday, October 1, 1992

A request from the ranks (I do requests, by the way. I live for requests):

Joe Lucia writes, "What I can't help but wonder is how you distinguish Gravity from the plethora of information mapping, storage, and exchange technologies that are already in place? Why is it necessary? What does it give us that others don't?"

I've been waiting for this. What Makes It Different. After reading Joe's
impatient request, I went to Penn Pizza and ordered the biggest stromboli yet recorded on the planet, stared at my Elliot's apple juice for about an hour, and built myself up to address the whole thing in a nutshell.

Today's note is wildly out of sequence, and intended mostly for the computer science folk, so feel free to skip this one as well. There will be quite a lot of techno-talk, and even worse, Tim-babble. This time I won't define my terms. I won't talk about intentions or reasons or what it all means.

Just this: Gravity describes an environment where information agents are collected in ThoughtShops where they get, change, and send text, images, sounds, and systems according to item-associated rules and according to the dictates of the agent's current context.

More slowly: Each agent has an internal storage structure called a
context. This is where the real cool stuff happens, and I'd be a fool if
I thought I could explain it all in this note. The context is the substrate
through which all information passes. This is a very crucial thing to realize about Gravity. Access causes Change. No two agents ever use the same item, because in transferring an item from one agent to the other, it changes. It changes Because it passes through the receiving agent's context.

There are only three verbs in the Gravity scheme. Agents know how to do only three things. Get, Send, and Change. They can't Add. They can't Print. They can't Save. They can't Run. They can't Quit.

And here's the rub... this is very, very, important. Every time an agent
Gets an item, it also Changes it and Sends it. Every time an agent Sends an item, it Gets something and Changes it. Every time an agent Changes an item, it Sends it and Gets something. The three actions always happen together. Just as Text/Image/Sound/System are four aspects of the same thing, Get/Change/Send are each a part of the same immutable process.

I've got nifty two letter words for Get, Change, and Send that may help you understand them:

Im means impression, input, things coming in ...GET...

Ex means expression, output, things going out ...SEND...

Mu means ..don't ask.. it's what happens in between ...CHANGE...

Together they form a process. Agents don't really do three things, they do ONE thing: Im-Mu-Ex. They immuex (pronounced im-myoo-ex). The going in and going out part is simple enough. It's that Mu part that's hard to describe.

To begin to understand Mu, know this: Gravity never forgets. Every item ever made is accessible by its agent. Any time something is changed, the previous version of it can still be accessed. Built into the whole philosophy of this plan is the assumption that nothing is ever lost. It's like an ultimate un-do, but the implications are much wilder than this may suggest.

Also, know this: the only things you'll find in an agent's context are names. Go back and read about names.... remember: OF / BY / AM / IF / SO. I didn't arrive at this combination overnight. The sequence is very important. How agent's immuex (that is, how their contexts affect the throughput of information) has everything to do with the syntax of a name. Also within that syntax lies a clue about how I pull of this Gravity Never Forgets thing.

As for what it gives us that the others don't... I could talk about this.
I could compare it to object-oriented databases, and rule-based processing systems, and distributed systems, and some of the representation/communication schemes around. I will, if you want me to.

But not today. If this note was confusing, don't worry. This is just a glimpse of the terrain ahead. We will spend much more time with agents, and ThoughtShops, and contexts, and rules, and names, and Mu.

Tomorrow: something completely different!

From: Steven Goldman