A system is not a pile of parts.系统不是零件的堆积。
It is parts, plus the connections between them, plus a purpose none of the parts ever voted on. Take it apart to understand it, and the very thing you wanted to understand — the behaviour over time — is the first thing to disappear.它是零件，加上零件之间的连接，再加上一个没有任何零件投过票的目的。为了理解它而把它拆开，那你最想理解的东西——它随时间展开的行为——会第一个消失。
This is why a system can be made of simple pieces and still refuse to behave simply. The behaviour lives in the wiring, not in the wires.所以一个系统可以由简单的部件构成，却拒绝简单地运转。行为住在接线方式里，而不在某一根线上。
Everything that accumulates is a stock.凡是会累积的，都是存量。
Water in a tub. Trust in a team. Carbon in the air. Money in an account. A stock changes only through its flows — and flows take time. A stock is the memory of every flow that came before it, which is why a level can keep rising for years after the tap was turned down.浴缸里的水。团队里的信任。空气中的碳。账户里的钱。存量只能通过流量改变——而流量需要时间。存量是此前所有流量的记忆，所以在龙头拧小很久之后，水位仍可能继续上升。
Two loops, and everything they make between them.两种回路，以及它们之间生出的一切。
Every arrow that leaves eventually comes home. Reinforcing loops multiply a change; balancing loops swallow it. Growth, collapse, oscillation, stubborn stability — all of it comes from a handful of these, wired together and running at different speeds.每一支射出的箭，最终都会回到家里。增强回路把变化放大；调节回路把变化吞掉。增长、崩溃、震荡、顽固的稳定——都不过是少数几个回路接在一起，以不同的速度同时运转。
More begets more多者更多
Interest on savings, rumours, erosion, a reputation. Left alone it runs away — in one direction or the other.利滚利、谣言、水土流失、口碑。没有约束时，它会一路奔逃——朝这一边，或那一边。
Seeking a goal寻找目标
A thermostat, a body's temperature, a market finding price. It hunts the target, overshoots, returns — and the delay decides how wild the hunt is.恒温器、体温、寻价的市场。它追逐目标、越过头、再折返——而时滞决定了这场追逐有多剧烈。
Sometimes, simply is not simple. You see a system running — running — and you pick up one point, and it is running still. 有时候，简单并不简单。你看见一个系统在运转——一直在运转——你拈起其中一个点，而它仍在运转。
The note this station was built from这座站点由这句笔记生长而来
Lift one point and you lift every arrow attached to it.拈起一个点，你也拈起了连在它身上的每一支箭。
A point in a system is not a thing; it is a position in a web. That is why the honest, obvious fix so often fails: you changed the number, and the loops around it simply re-absorbed the change and carried on. Policy resistance, Forrester called it — the counter-intuitive behaviour of social systems.系统中的一个点不是一件东西，而是网中的一个位置。所以那些诚实而显然的修补常常失败：你改动了那个数字，而围绕它的回路只是把改动重新吸收，然后照旧运转。福瑞斯特称之为「政策阻力」——社会系统的反直觉行为。
And the system never pauses to be examined. It answers your question with the whole of itself, in its own time, while still running.而系统从不为了被观察而暂停。它以自身的全部、按自己的节奏回答你的问题——并且始终在运转之中。
So where is it worth putting your hand?那么，手该落在哪里？
Donella Meadows ranked twelve places to intervene in a system, from the ones we reach for first to the ones that actually move things. Read from the bottom up.德内拉·梅多斯为「介入系统的十二个地方」排了序：从我们最先伸手去够的，到真正能撼动局面的。请由下往上读。
- 12Numbers — constants and parameters: subsidies, taxes, standards数字 — 常数与参数：补贴、税率、标准
- 11Buffers — the size of stabilising stocks缓冲 — 稳定性存量的规模
- 10Structure — how material stocks and flows are arranged结构 — 物质存量与流量的布置方式
- 09Delays — their length, relative to the rate of change时滞 — 相对于变化速度的长短
- 08Balancing loops — the strength of negative feedback调节回路 — 负反馈的强度
- 07Reinforcing loops — the gain around positive feedback增强回路 — 正反馈的增益
- 06Information flows — who gets to see what, and when信息流 — 谁在什么时候看得见什么
- 05Rules — incentives, punishments, constraints规则 — 激励、惩罚与约束
- 04Self-organisation — the power to add and evolve structure自组织 — 增添并演化结构的能力
- 03Goals — what the system is actually trying to do目标 — 系统真正在追求的东西
- 02Paradigms — the mindset the system grows out of范式 — 系统由之生长的心智模式
- 01Transcending paradigms — holding none of them as final超越范式 — 不把任何一个当作终局
Meadows, 1999 — ordered least → most effective. Full essay in reference 08.梅多斯，1999 — 由弱到强排序。全文见参考文献 08。
Where this came from这些说法的来处
The overview, the stock-and-flow notation and the causal loop diagrams above follow the standard sources below. Every link opens the original.上文的概览、存量—流量记号法与因果回路图，均依循以下常用文献。每个链接都通往原文。
- 01 Systems thinking — Wikipedia The overview this station started from.本站点的起点：总览词条。 en.wikipedia.org/wiki/Systems_thinking
- 02 Causal loop diagram R and B loops, link polarity, notation.增强与调节回路、极性与记号法。 en.wikipedia.org/wiki/Causal_loop_diagram
- 03 Stock and flow Accumulations, rates, and the bathtub.累积、速率，以及那个浴缸。 en.wikipedia.org/wiki/Stock_and_flow
- 04 System dynamics Forrester's method for simulating stocks, flows and delays.福瑞斯特用以模拟存量、流量与时滞的方法。 en.wikipedia.org/wiki/System_dynamics
- 05 Feedback Positive and negative feedback across disciplines.跨学科视野下的正负反馈。 en.wikipedia.org/wiki/Feedback
- 06 Emergence Why the whole does what no part does.为何整体会做出任何部分都不做的事。 en.wikipedia.org/wiki/Emergence
- 07 Systems theory Bertalanffy's general systems theory and its lineage.贝塔朗菲的一般系统论及其谱系。 en.wikipedia.org/wiki/Systems_theory
- 08 Meadows — Leverage Points: Places to Intervene in a System The full twelve, in her own words.十二个杠杆点的完整原文。 donellameadows.org/archives/leverage-points-places-to-intervene-in-a-system/
- 09 Donella Meadows Author of Thinking in Systems: A Primer.《系统之美》（Thinking in Systems）作者。 en.wikipedia.org/wiki/Donella_Meadows
- 10 Jay Wright Forrester Founder of system dynamics; policy resistance.系统动力学奠基者；「政策阻力」的提出者。 en.wikipedia.org/wiki/Jay_Wright_Forrester
- 11 Peter Senge — The Fifth Discipline Systems thinking inside organisations; archetypes.组织中的系统思考与系统基模。 en.wikipedia.org/wiki/The_Fifth_Discipline
- 12 Beer distribution game Delay and oscillation you can feel with your own hands.亲手就能体会的时滞与震荡。 en.wikipedia.org/wiki/Beer_distribution_game
- 13 The Limits to Growth The most argued-about system model ever built.史上争论最多的一个系统模型。 en.wikipedia.org/wiki/The_Limits_to_Growth
- 14 Variety — the law of requisite variety Ashby: only variety can absorb variety.艾什比：唯有多样性能吸收多样性。 en.wikipedia.org/wiki/Variety_(cybernetics)