I introduced some ideas from systems thinking last month, and especially the idea of second order cybernetics: the study of how people’s perceptions of systems affect their ability to understand and control them. I want to pick up on this idea, because I think it’s crucial to understanding the predicament we’re now in with respect to climate change. The system of systems that we have to understand in order to grasp the challenges of climate change is so complex that naturally, everyone sees it a little differently.

When describing relatively simple systems, most people’s descriptions coincide to some degree. Typically, one person will give more detail than another, such that the simpler description is completely subsumed in the more detailed one. However, for more complex systems, different people’s descriptions tend to diverge more. For any reasonably complex system, it will be impossible to completely derive any one person’s description from another persons – each will offer unique details that the other missed.¬†Weinberg dubs this the¬†principle of complementarity in his book on General Systems Thinking: any two descriptions of a complex system are likely to be complementary.

Here’s a simple example – these two photos are of the same lake, but are complementary views:

The principle applies whenever we have partial descriptions of the world from our observers, and may disappear if we ask the observers to make increasingly detailed observations. Assuming they really are describing the same system, it should eventually be possible to reconcile their descriptions completely. For example, with a little effort, you can match up the peaks in the two photos above, and even some of the trees (it’s a little easier with the enlarged photos – click on them for bigger).¬†Unfortunately, if the systems are complex enough, the descriptions can only ever be partial, and it may be infeasible to trace down every last detail in order to reconcile them.

When it comes to climate, the principle of complementarity works overtime. People end up talking past one another because they don’t even realise they’re describing the same systems – their descriptions appear to have no common ground. For example, one person might talk in terms of atmospheric carbon concentrations, and emphasize the need to stop using fossil fuels. Another person might talk in terms of the costs of climate policies, and the risk to the economy if we place a price on carbon. Because they don’t stop to explore how the systems they are describing inter-relate, they don’t understand that they are each focussing on just one part of a much larger system of systems.

And the problem is that most people are so embedded in a particular worldview, they are incapable of understanding the systems in the way that others see them. To illustrate the depth of this problem, consider this story from Bill Tomlinson’s book “Greening through IT“:

One day, when I was in graduate school, I was walking along a paved bicycle path near my Davis Square apartment in Somerville, Massachusetts, on the way to the T station (the Boston area subway). A father and son were walking a few yards in front of me. The boy was about four years old. He was running back and forth across the path, looking under rocks and investigating things. I saw him find something small, pick it up, and carry it over to his father. I heard the father say, “Oh, you found a snail!” I could feel a life lesson about to ensue. “Let’s see how far you can chuck that snail, Bobby!” (p109)

I feel a strong sense of revulsion towards this father, because my values are very different from his. I see the snail as a fascinating creature, to be studied and admired for its behaviours, and it’s interaction with the urban environment in which it lives – my kids and I have spend ages admiring how they wave their feelers and how they move. The father in the story sees the snail as part of a system of objects that can be hefted and thrown in sport. But this is just the principle of complementarity at work: we’re focussing on very different systems, which overlap. If we can’t step back and understand how our different values cause us to have complementary views of the ‘same’ system, then we’ll never manage to reach agreement on the broader goals of tackling a problem as complex as climate change.


  1. Awesome piece that ended with a bit of a thud. Can you think of a significant system on which “we” have reached agreement on broader goals? I can’t. When I read history, the stories of positive, country-scale action in a crisis come because a few whose view of the problem is trenchant manage to get their hands on the reins and make a difference despite the incomprehension of the many. Often they deliberately disavow key facets of their perspective. Think of FDR in 1940 — or for that matter, Hitler in 1930 (the solution need not be positive). When it comes to the crux of a major internal conflict — think the U.S. and race since 1865, or England and the shift to democracy from say 1665 to 1920 — the big turning points are never accompanied by those of different values “stepping back” and “understanding.” Deliberate deception is often a key tactic of progress.

    Note that I deliberately chose periods that began in the aftermath of civil war: war can motivate a certain kind of “stepping back” and “shared understanding”: “They’re trying to kill us! Let’s kill them first!”

    My broader point is to suggest that the scientific community is not and should not be a model for the human community. It is not necessarily a virtue to insist on participating in one’s larger community “as a scientist” when that conflicts with

  2. @Sam: Yes, the conclusion was rather weak. I don’t think it’s necessary to reach agreement on values and goals, but it *is* important to understand how they diverge. I take your point. But great political leaders *do* manage to find some common values, or at least some rhetoric that appeals to common values, in order to push through changes that most people won’t understand, and which people may well resist if presented differently.
    The (1) in the title means I’m planning several more posts on this topic, so I hope to draw out some better conclusions eventually….

  3. (… whoops; submitted accidentally. As I was saying … )

    I believe you correctly perceive a deep conflict between the mores of participating in the scientific community and the mores of participating in society. I interpret your last sentence as an assertion that the real problem is getting society to function more like the scientific community. The negative phrasing “if we can’t” suggests that perhaps you have some doubts about the viability of this approach, doubts I wish to encourage :-). Citizenship as such is not inferior to science as such. Henry Waxman and Nancy Pelosi need not kowtow to James Hansen because they are members of a lesser caste.

    That political engagement looks like an endless series of morally compromising haggles from a certain angle is no more significant than that tenured research looks like self-indulgent freeloading and exploitation of grad students from a certain angle. Since we all agree that we political action much more desperately than we need better science, hand-wringing over the ways in which the former fails to follow the moral paradigms of the latter is something to move past in my humble opinion. One useful tactic might be to look with a clear eye at the alternative to politics when societies are in serious conflict, which is war.

  4. The snail story stuck with me as though I were the one pelted by it. I have similar stories, e.g., seeing a harmless snake on the way to a community gathering and returning to find its carcass, thanks to someone’s sense of duty.

    So I’m trying to imagine the systems at work in the climate change debate. I understand your example of the climate system vs economic system and each person having their viewpoint. But a different person spouting water vapor, global warming on Mars, and ‘hide the decline’ in my newspaper’s opinion section is not oberving any real system (and their are many of these people). I guess they’re part of a belief system, which is part of the overall consilience (I think that’s the term) of knowledge. But still when viewed at that level, there’s reality and non-reality. I can’t give the members of non-reality any credible perspective that can be reconciled with mine.


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