By Greg Fisher
Among the people I talk to about complex systems, a common point made is that the future is inherently uncertain or “unknowable”. I have emphasised this myself in a number of blogs and papers – it results from the concept of emergence “breaking” determinism (as well as from quantum uncertainty). But in this blog I want to flesh out what I mean when I say “the future is inherently unknowable” because the issue is much more nuanced than this statement implies, and because I would like to provoke some discussion. I should mention that it was a conversation with my colleague Rhett Gayle that catalysed this blog, after he rightly questioned my use (as well as that of others) of this phrase.
At the heart of my argument are two points: (i) it’s important to distinguish between randomness and complex systems because the latter includes patterns whereas the former does not; and (ii) it is patterns that determine our ability to anticipate and / or influence the future. In this blog, let me define “patterns” as systematic relationships between the component parts of some complex system that are expected to persist for a period of time. My colleague Hank Sohota offered an alternative definition: “patterning” is a population wide tendency to think and / or behave in a particular way.
It is informative to distinguish between patterns and laws. The latter involve universality in time and space i.e. they are eternal and they are expected to operate in all circumstances and contexts (consider, for example, natural laws). By contrast, patterns are ultimately ephemeral and context always matters. In fact, we could think of laws as a special type of pattern: eternal and context independent. My reference to patterns has sometimes been misinterpreted as being about laws – that is not what I mean.
There is also the important question of identifiability. Many patterns in human systems are tacit or implicit to varying degrees, rendering them difficult or impossible to identify and – even if identification were possible – to quantify. As an aside, many traditional economists try to identify the eternal laws of economic behaviour because they think of a whole economic system as both unchanging and, implicitly, quantifiable.
The point I want to emphasise in this blog is that it is these two issues – the extent to which patterns persist and whether they are identifiable – that largely determine the degree to which we can be precise (or be confident) in predicting or influencing the future. A good way to think about this is to consider that patterns exist alongside emergent effects, which are unpredictable by definition and might appear to be random. So it is patterns that provide us with some basis of prediction but they’re not everything – the world is constantly evolving – so we find ourselves in a weird situation of “semi-predictability”. We live in a world in which “black swan events” live along side relatively stable patterns (such as language).
Let’s look at randomness for a moment. If everything around us in our universe were random, we wouldn’t exist and this blog would not be possible. There would be no natural laws (or, if there were, they would be random – in which case they wouldn’t be very good laws), and there would be no forms of self-organisation (such as energy existing as mass and sub-atomic particles combining to make up atoms). But consider a thought experiment: suppose we take a less extreme version of randomness, say one in which we do exist but nothing around us were predictable, what then? Well, to be frank, there wouldn’t be much point in getting up in the morning. We wouldn’t know (for example) if people still spoke English, obeyed laws such as prohibition concerning murder, used the currency in their pocket, drove on the left side of the road (for those in the UK), or could be trusted (etc. etc. etc.). It would be a weird world in which to live and we probably wouldn’t survive for very long because it’s more than likely we’d soon be killed by a random act.
We don’t live in a random world because patterns have emerged. They have created all of the order around us and by and large we expect most of this order – these patterns – to continue. By “order” I do not mean that the societies in which we live are ordered in the same way as Laplace’s clockwork universe. Nor do I mean that all patterns are only socially useful. I just mean that there are forms of systematic relationships between people (and technology) that have facilitated our survival and what we understand as “order”. Given my definition of patterns, this means that language is a type of pattern, as are laws, money, which side of the road we drive on, and trust. In fact I would posit that we could call everything non-random in the universe a pattern.
There is a relationship between patterns and prediction. In fact, I would note that not only do patterns exist and persist, we must rely on them in every day life. We make decisions in the present assuming the persistence of some patterns e.g. I will withdraw £50 from a cash machine today for spending over the next few days. I do not expect everyone else in the UK to switch to the Thai Baht during that period. Furthermore, it is particular patterns – many of which we might call institutions – that are responsible for our civilised society and a relatively high standard of living.
But – and this is to assert the point further – it is important to emphasise that the world will change and so too will the patterns around us. By “expect to persist” in my definition of patterns I was referring to making reasonable judgments that some patterns will remain broadly the same over a particular period.
To conclude, it is easy to conflate the original point of “the future is unknowable” and randomness. The two are not the same. If we live in a world that includes some predictable patterns and apparent randomness due to emergent effects, this statement is true but not in extremis. Let’s not be too coarse-grained about this issue.
There are a number of implications of this mixture of patterns and emergence (apparent randomness) for public policy, which I will turn to in a future blog.