A modular system is one whose essentially similar parts, subassemblies or holons have substantial self-reliance and independence. Modularity is intrinsic to resilience and is the counterpart of complexity (for modular systems in context with the four types of system discussed in Lean Logic, see the summary table in Systems Thinking ).

Its three critical properties are:

1. dispersal (weak interdependence between its parts, which prevents a shock rippling through the whole system);

2. flexibility (the substantial freedom of parts to act in diverse ways in their own and/or the system’s interests); and

3. small scale of its parts (conferring the benefits of elegance, judgment and presence).

Modularity gives the parts of a system the critical quality of recovery-elastic resilience, but a modular system does have limitations. Its weak interdependence means that it lacks the connected brilliance of a complex system—even if the independent holons that it is made up of are themselves complex systems. For example, communities, being less complex than their members, find it hard to match their members’ intelligence; likewise, groups of communities, being more modular than the communities which are their members, are no match for the intelligence of the communities they represent.

It is a common experience for intelligent people to be dismayed at the obtuseness of the community they live in, or for communities to be dismayed at the obtuseness of government. This is not always because the man and woman in the pub think they can run the country better, nor because collective policy has to be agreed with those with least perceptiveness as well as those with most. It is because the modular system is intrinsically incapable of complex strategy. Its lack of connectedness, left to itself, leaves it stupid. It is capable, like a herd of antelopes, of doing simple-minded things like running away. And it can, crucially, do the most vital thing of all—act as the stable, non-interventionist but supportive setting for diversity, brilliance, learning, politics, freedom, elegance, elasticity and recovery. It gives the complex systems that comprise it (the creatures that live there), the freedom to develop their potential. But it cannot itself sustain a complex idea and make complex connections, nor can it carry out a complex policy . . .

. . . unless, that is, it evolves incrementally into an ‘as-if complex’ system (what Lean Logic terms a “complicated system”). This is clearly a tricky idea, even by the standards of the clutch of ideas surrounding resilience, complexity and modularity. The argument, as fleshed out in the entry on complexity, goes roughly like this:

A modular system can be shoe-horned into a form of ‘as-if complexity’ by an ambitious process of intensification, with specialisation, division of labour and increased connectedness. Parts which were formerly self-reliant become dedicated providers of one thing to the wider system (and importers of everything else); despite their weak diversity of form, they take on a wide variety of functions. A drift into complication can end the quiet life of a modular system, launching it on the path towards a spectacular future (though maybe also a short one).

Modular systems, then, given time, can sometimes develop an ‘as-if complexity’ of their own—brains are not the only things that are capable of intelligence. As Steven Johnson writes, an ant colony has . . .

. . . collective intelligence. . . . Ten thousand ants, each limited to a meagre vocabulary of pheromones and minimal cognitive skills—collectively engage in nuanced and improvisational problem-solving. . . . There is decentralised intelligence.M20

That is, it has some of the properties of a brain. The common purpose establishes the connections; and the serial interactions among those connections produce a collective intelligence which is closely attuned to the purpose. If deeply engaged people can think in the same way, their group may begin to acquire some of the connectedness and competence of a complex system. For examples, we can look to groups such as the dedicated Little Sisters of Mercy, whose shared lives are based on the common purpose of caring for their patients, or the circle of scientists, natural philosophers, engineers and entrepreneurs who met regularly for “philosophical feasts” in London and the Midlands of the UK in the late eighteenth century (known as the Lunar Society). The story is taken up by one of the “Lunarticks”—as they called themselves—the inventor Richard Edgeworth:

Arguments were fierce and fools were jeered, but as the knowledge of each member of such a society becomes in time disseminated through the whole body, so the talents of numbers could forward the ideas of a single person.M21

And the historian Lisa Jardine, speaking of the early years of The Royal Society, develops this . . .

The really defining quality of a group like the Royal Society is that they can bounce ideas off each other. Very few people make enormous change; it’s groups together that do that. The isolated great man may light the touch-paper but it’s the group. And that’s true even with Newton. The great man isolated in his ivory tower can do the mathematics. That’s lighting the touch-paper. Expanding that into the Inverse Square Law and the laws of gravity—that takes a group.M22

A system or community whose interdependencies or shared culture are too weak will not achieve that; and nor will top-down decision-making that does not recognise its holons as being competent at all. But a degree of interconnectedness within even a modular system can confer the ability to think—the development, in some senses, of a collective mind.M23

Now for the twist: if the wider group or society becomes more complicated, connected and closely-coupled, the holons or parts of that system may find that their own complexity declines. The complexity of the whole is predatory on the complexity of its parts. It is jealous of their competence. For example, consider a network of complex, self-reliant villages. If the complexity of each village, consisting of diverse, interdependent parts, remains intact, then they are relatively unlikely to be compliant to the demands of a higher-level complex system to which they in turn belong (Character). There is in these circumstances a trade-off: increased complexity of the whole comes at the cost of decreased complexity of the parts. The (ultimately fatal) weakness that destroys the resilience of a tightly-coupled, rigid, large-scale system arises as much from the weakened complexity of its deskilled, fragmented parts as from the increased connectedness—the brittle inflexibility—of the system as a whole.


To take it to the extreme, chaos is perfect modularity, zero complexity—perfectly resilient in the sense of being indestructible, since there is no order there in the first place; nothing to destroy. At the other extreme—zero modularity, full complexity—a system is so tightly connected up that it is unable to function at all, and quickly destroys itself. Between the two we find, not the edge of chaos—that thin line of complexity and meaning—but a spectrum. Towards one end of that spectrum we find the strong complexity (and preventive resilience) of, for instance, the antelope, and towards the other, the strong modularity (and recovery-elastic resilience) of a herd of antelopes.

Complexity provides good judgment; modularity makes the space for it to act on that judgment. And the union of opposites—complex parts within a wider modular system—gives us more than resilience. It gives us the brilliance of the ecological system, capable of containing and supporting such taut, elegant systems as the nightingale. Complexity is the fine delight that fathers thought; modularity leaves yet the mind a mother of immortal song.M24


Related entries:

Nation, TEQs (Tradable Energy Quotas), Butterfly Effect, Resilience > Resilient Systems.

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David Fleming
Dr David Fleming (2 January 1940 – 29 November 2010) was an economist, historian and writer, based in London. He was among the first to reveal the possibility of peak oil's approach and invented the influential TEQs scheme, designed to address this and climate change. He was also a significant figure in the development of the UK Green Party, the Transition Towns movement and the New Economics Foundation, as well as a Chairman of the Soil Association. His wide-ranging independent analysis culminated in two critically acclaimed books, Lean Logic and Surviving the Future. A film about his perspective and legacy - The Sequel: What Will Follow Our Troubled Civilisation? - was released in 2019, directed by BAFTA-winning director Peter Armstrong. For more information, including on Lean Logic, click the little globe below!

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