Chapter 4Touch one, touch all
In the net, every knot is tied to every other one. The world we live in ain't quite that tight — you don't know everybody. But you know somebody who knows somebody, and it turns out that's near as good.
A ring of neighbors
Start with folks in a big circle, each one holdin' hands with the two on either side, and the two past that. Tell one person some news. It goes one hop at a time around the ring, both directions. With 1,000 people each holdin' ten hands, the average person is 50.45 hops from any other. Slow goin'.
Move a few hands
Now take one handhold in a hundred and hook it to a stranger clear across the ring. That's all. The average drops to 8.82 hops. One in ten, and it's 4.38. Your neighbors are still mostly your neighbors — the share of your friends who know each other barely moves, from 0.667 to 0.647 — but the world got small25. Duncan Watts and Steven Strogatz worked that out in 1998. Stanley Milgram had seen it with letters thirty years before24.
- 0% long
- 50.45 hops on average · friends-know-each-other 0.667
- 0.1% long
- 19.33 hops · 0.664
- 1% long
- 8.82 hops · 0.647
- 10% long
- 4.38 hops · 0.483
- All random
- 3.27 hops · 0.009
1,000 knots, ten hands each, computed on this site's own machine with a fixed seed.
What this has to do with jewels
Indra's net is the far end of that table: every knot tied straight to every other, zero hops. Our world sits in the middle — mostly neighbors, a few long ties — and that's enough that a nudge in one corner gets everywhere in a handful of steps. Gossip does it. So does a cold. So does a kindness. Plucked one jewel, and the whole net trembled: that's the demo on the front page, and it's this.