Tag Archives: emergent behaviour

Do you believe in an afterlife?

‘I believe that energy can’t be destroyed, it can only be changed from one form to another.  There’s more to life than we can conceive of.’ The quote is from the singer and songwriter, Corinne Bailey Rae’s answer to the question: do you believe in an afterlife? [see Inventory in the FT Magazine, October 26/27 2019].  However, the first part of her answer is the first law of thermodynamics while the second part resonates with Erwin Schrödinger’s view on life and consciousness [see ‘Digital hive mind‘ on November 30th, 2016]. The garden writer and broadcaster, Monty Don gave a similar answer to the same question: ‘Absolutely.  I believe that the energy lives on and is connected to place.  I do have this idea of re-joining all of my past dogs and family on a summer’s day, like a Stanley Spencer painting.’ [see Inventory in the FT Magazine, January 18/19 2020].  The boundary between energy and mass is blurry because matter is constructed from atoms and atoms from sub-atomic particles, such as electrons that can behave as particles or waves of energy [see ‘More uncertainty about matter and energy‘ on August 3rd 2016].  Hence, the concept that after death our body reverts to a cloud of energy as the complex molecules of our anatomy are broken down into elemental particles is completely consistent with modern physics.  However, I suspect Rae and Don were going further and suggesting that our consciousness lives on in some form. Perhaps through some kind of unified mind that Schrödinger thought might exist as a consequence of our individual minds networking together to create emergent behaviour.  Schrödinger found it utterly impossible to form an idea about how this might happen and it seems unlikely that an individual mind could ever do so; however, perhaps the more percipient amongst us occasionally gets a hint of the existence of something beyond our individual consciousness.

Reference: Erwin Schrodinger, What is life? with Mind and Matter and Autobiographical Sketches, Cambridge University Press, 1992.

Image: ‘Sunflower and dog worship’ by Stanley Spencer, 1937 @ https://www.bbc.co.uk/news/entertainment-arts-13789029

Destruction of society as a complex system?

Sadly my vacation is finished [see ‘Relieving stress‘ on July 17th, 2019] and I have reconnected to the digital world, including the news media.  Despite the sensational headlines and plenty of rhetoric from politicians, nothing very much appears to have really changed in the world.  Yes, we have a new prime minister in the UK, who has a different agenda to the previous incumbent; however, the impact of actions by politicians on society and the economy seems rather limited unless the action represents a step change and is accompanied by appropriate resources.  In addition, the consequences of such changes are often different to those anticipated by our leaders.  Perhaps, this is because society is a global network with simple operating rules, some of which we know intuitively, and without a central control because governments exert only limited and local control.  It is well-known in the scientific community that large networks, without central control but with simple operating rules, usually exhibit self-organising and non-trivial emergent behaviour. The emergent behaviour of a complex system cannot be predicted from the behaviour of its constituent components or sub-systems, i.e., the whole is more than the sum of its parts.  The mathematical approach to describing such systems is to use non-linear dynamics with solutions lying in phase space.  Modelling complex systems is difficult and interpreting the predictions is challenging; so, it is not surprising that when the actions of government have an impact then the outcomes are often unexpected and unintended.  However, if global society can be considered as a complex system, then it would appear that its self-organising behaviour tends to blunt the effectiveness of many of the actions of government.  This seems be a fortuitous regulatory mechanism that helps maintain the status quo.   In addition, we tend to ignore phenomena whose complexity exceeds our powers of explanation, or we use over-simplified explanations [see ‘Is the world incomprehensible?‘ on March 15th, 2017 and Blind to complexity‘ on December 19th, 2018].  And, politicians are no exception to this tendency; so, they usually legislate based on simple ideology rather than rational consideration of the likely outcomes of change on the complex system we call society. And, this is probably a further regulatory mechanism.

However, all of this is evolving rapidly because a small number of tech companies have created a central control by grabbing the flow of data between us and they are using it to manipulate those simple operating rules.  This appears to be weakening the self-organising and emergent characteristics of society so that the system can be controlled more easily without the influence of its constituent parts, i.e. us.

For a more straightforward explanation listen to Carole Cadwalladr’s TED talk on ‘Facebook’s role in Brexit – and the threat to democracy‘ or if you have more time on your hands then watch the new documentary movie ‘The Great Hack‘.  My thanks to Gillian Tett in the FT last weekend who alerted me to the scale of the issue: ‘Data brokers: from poachers to gamekeepers?


Blind to complexity

fruit fly nervous system Albert Cardona HHMI Janelia Research Campus Welcome Image Awards 2015When faced with complexity, we tend to seek order and simplicity.  Most of us respond negatively to the uncertainty associated with complex systems and their apparent unpredictability.  Complex systems can be characterised as large networks operating using simple rules but without central control which results in self-organising behaviour and non-trivial emergent behaviour.  Emergent behaviour is the behaviour of the system that is not apparent or expected from the behaviour of its constituent parts [see ‘Emergent properties‘ on September 16th, 2015].

The philosopher, William Wimsatt observed that we tend to ignore phenomena whose complexity exceeds our predictive capability and our detection apparatus.  This is problematic because we try to over-simplify our descriptions of complex systems.  Occam’s razor is often mis-interpreted to mean that simple explanations are better ones, whereas in reality ‘everything should be made as simple as possible, but not simpler’, (which is often attributed to Einstein).  This implies that our explanation and any mathematical model of a complex system, such as the nervous system in the image, will need to be complex.  In mathematical terms, this will probably mean a non-linear dynamic model with a solution in the form of a phase portrait.  ‘Non-linear’ because the response of the system not proportional to the stimulus inducing the response; ‘dynamic’ because the system changes with time; and a ‘phase portrait’ because the system can exist in many states, some stable and some unstable, dependent on its prior history; so, for instance for a pendulum, its phase portrait is a plot of all of its possible positions and velocities.

If all this sounds too hard, then you see why people shy away from using complex models to describe a complex system even when it is obvious that the system is complex and extremely unlikely to be adequately described by a linear model, such as for the nervous system in the image.

In other words, if we can’t see it and its too hard to think about it, then we pretend it’s not happening!


The thumbnail shows an image of a fruit-fly’s nervous system taken by Albert Cardona from HHMI Janelia Research Campus.  The image won a Wellcome Image Award in 2015.

William C. Wimsatt, Randomness and perceived randomness in evolutionary biology, Synthese, 43(2):287-329, 1980.

For more on this topic see: ‘Is the world comprehensible?‘ on March 15th, 2017.


Red to blue

Some research has a very long incubation time.  Last month, we published a short paper that describes the initial results of research that started just after I arrived in Liverpool in 2011.  There are various reasons for our slow progress, including our caution about the validity of the original idea and the challenges of working across discipline boundaries.  However, we were induced to rush to publication by the realization that others were catching up with us [see blog post and conference paper].  Our title does not give much away: ‘Characterisation of metal fatigue by optical second harmonic generation‘.

Second harmonic generation or frequency doubling occurs when photons interact with a non-linear material and are combined to produce new photons with twice the energy, and hence, twice the frequency and half the wavelength of the original photons.  Photons are discrete packets of energy that, in our case, are supplied in pulses of 2 picoseconds from a laser operating at a wavelength of 800 nanometres (nm).  The photons strike the surface, are reflected, and then collected in a spectrograph to allow us to evaluate the wavelength of the reflected photons.  We look for ones at 400 nm, i.e. a shift from red to blue.

The key finding of our research is that the second harmonic generation from material in the plastic zone ahead of a propagating fatigue crack is different to virgin material that has experienced no plastic deformation.  This is significant because the shape and size of the crack tip plastic zone determines the rate and direction of crack propagation; so, information about the plastic zone can be used to predict the life of a component.  At first sight, this capability appears similar to thermoelastic stress analysis that I have described in Instructive Update on October 4th, 2017; however, the significant potential advantage of second harmonic generation is that the component does not have to be subject to a cyclic load during the measurement, which implies we could study behaviour during a load cycle as well as conduct forensic investigations.  We have some work to do to realise this potential including developing an instrument for routine measurements in an engineering laboratory, rather than an optics lab.

Last week, I promised weekly links to posts on relevant Thermodynamics topics for students following my undergraduate module; so here are three: ‘Emergent properties‘, ‘Problem-solving in Thermodynamics‘, and ‘Running away from tigers‘.