The mechanism
Thousands of traders, no shared plan, no communication. Yet they place orders at strikingly similar prices. The reason is structural, not coordinated: when people need to converge without communicating, they gravitate to the points that are "obvious" to everyone — the ones that stand out, that anyone would guess the others would also guess.
Thomas Schelling formalized this in 1960 with the idea of the focal point (later called a Schelling point): in a coordination problem without communication, players converge on whatever solution is salient, prominent, or natural in the shared context. His famous example: two strangers told to meet in New York City on a given day, with no way to communicate, disproportionately choose Grand Central at noon. Nothing forced it. It was simply the obvious answer that each expected the other to also find obvious.
Markets are full of these obvious answers. The high and low of the daily, weekly, and monthly candle. The session open and close. Round numbers. The level a widely-watched indicator prints. None of these is special in itself. They become special because everyone can see that everyone else can see them — so that is where resting orders, stops, and attention pile up.
Why focality concentrates liquidity
A focal level is self-fulfilling in a specific, mechanical way. Because participants expect price to react there, they place orders there — bids, offers, stops, take-profits. That clustering makes the level a genuine pocket of liquidity. So when price arrives, there is something real to interact with: orders to absorb the move, stops to trigger, a reason for the reaction the participants expected. The expectation built the structure that justified the expectation.
This is the bridge to the other conditions. Focality decides where liquidity accumulates; finitude decides that this accumulated liquidity is finite and will be consumed; reflexivity is what happens once traders notice the reaction and start trading the level deliberately.
What it gives the trader
Focality is the structural reason support and resistance are not pure superstition. The levels work — when they work — because they are focal: visible to all, and therefore where orders collect. It also tells you which levels to weight. The more obvious a level is to the broadest set of participants (a weekly high beats an obscure intraday wick), the more focal it is, and the more liquidity it should gather.
You cannot eliminate focality. You cannot stop humans from looking at the same obvious points. The only way to remove it would be to make participants unable to see the chart everyone else sees.