Tag Archives: science

Opal offers validation opportunity for climate models

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OrangeFanSpongeSmallMany of us will be familiar with the concept of the carbon cycle, but what about the silicon cycle?  Silicon is the second most abundant element in the Earth’s crust.  As a consequence of erosion, it is carried by rivers into the sea where organisms, such as sponges and diatoms (photosynthetic algae), convert the silicon in seawater into opal that ends up in ocean sediment when these organisms die.  This marine silicon cycle can be incorporated into climate models, since each step is influenced by climatic conditions, and the opal sediment distribution from deep sea sediment cores can be used for model validation.

This approach can assist in providing additional confidence in climate models, which are notoriously difficult to validate, and was described by Katharine Hendry, a Royal Society University Research Fellow at the University of Bristol at a recent conference at the Royal Society.  This struck me as an out-of-the box or lateral way of seeking to increase confidence in climate models.

There are many examples in engineering where we tend to shy away from comprehensive validation of computational models because the acquisition of measured data seems too difficult and, or expensive.  We should take inspiration from sponges – by looking for data that is not necessarily the objective of the modelling but that nevertheless characterises the model’s behaviour.

Source:

Thumbnail: http://www.aquariumcreationsonline.net/sponge.html

A liberal engineering education

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115-1547_IMGFredrik Sjoberg points out how the lives of Darwin and Linnaeus have become models for generations of natural scientists.  Youthful travels followed by years of patient, narrowly focussed research and finally the revolutionary ideas and great books.  Very many scientists have followed the first two steps but missed out on the last one, leaving them trapped in ‘the tunnel vision of specialised research’.  As our society and its accompanying technology has become more complex, more and more tunnels or silos of specialised knowledge and research have been created.  This has led specialists to focus on solving issues that they understand best and communicating little or not at all with others in related fields.  At the same time, our society and technologies are becoming more interconnected, making it more appropriate to cross the cultural divides between specialisms.

One of the pleasures of teaching my current MOOC is the diversity of learners in terms of gender, geography and educational background who are willing to cross the cultural divides.  We have people following the MOOC in places as diverse as Iceland, Mexico, Nigeria and Syria.  We have coffee bean growers, retired humanities academics, physical chemists and social historians.  In most of the western world, engineering is taught to male-dominated classes and this has remained a stubborn constant despite strenous efforts to bring about change.  So it is a pleasure to interact with such a diverse cohort of people seeking to liberate their minds from habit and convention.

The original meaning of the term ‘liberal studies’ was studies that liberated students’ minds from habit and convention.  Recently, Vinod Khosla has suggested that we should focus on teaching our students ‘liberal sciences’.     This seems to connect with the ’emotive traits’ that David Brooks has proposed will be required for success in the future, when machines can do most of what humans do now (see my post entitled ‘Smart Machines‘ on February 26th, 2014).  These emotive traits are a voracious lust of understanding, an enthusiasm for work, the ability to grasp the gist and an empathetic sensitivity for what will attract attention.   We don’t teach much of any of these in traditional engineering degrees which is perhaps why we can’t recruit a more diverse student population.  We need to incorporate them into our degree programmes, reduce much of the esoteric brain-twisting analysis and encourage our students to grapple with concepts and their broader implications.  This would become a liberal engineering education.

Sources:

Fredrik Sjoberg, The Fly Trap, Penguin Books, 2015

Asish Ghosh, Dynamic Systems for Everyone: Understanding How Our World Works, Springer, 2015

Vinod Khosla, Is majoring in liberal arts a mistake for students? Medium, February 10th, 2016

David Brooks, What machines can’t do, New York Times, February 3rd, 2014

 

 

Laws of biology?

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daisyMany people are familiar with Newton’s Laws of Motion and, perhaps aware of the existence of the laws of thermodynamics. These are fundamental laws of physics upon which much of our engineered world is built. But, are there corresponding fundamental laws of biology? The question is important because we need to understand the interaction of engineered products and services with the biological world (including us) because, as John Caputo has suggested, a post-humanist world is coming into existence as the boundary between humans and technology is eroded.

So, back to laws of biology.  It is challenging to identify predictive statements about the biological world that are generally applicable. Elliott Sober argued that there are no exceptionless laws in biology. However, others would point to Dollo’s law that states evolution is irreversible, which sounds like a form of the second law of thermodynamics: entropy increases in all real processes. Indeed, McShea and Brandon have written a book entitled ‘Biology’s First Law: the tendency for diversity and complexity to increase in evolutionary systems’ which sounds even more like the second law of thermodynamics.

There are other candidates such as the Hardy-Weinberg law that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences; maybe this is corollary of Dollo’s law?   Or, the Michaelis-Menten rate law that governs enzymatic reactions. But, are there any biological laws that are sufficiently general to apply beyond the context of life on Earth?  Answers via comments, please!

Sources:

Caputo JD. Truth: philosophy in transit. London: Penguin, 2013.

Sober, E., Philosophy of biology, Boulder CO: Westview Press, 1993.

Sober, E., Philosophy in biology, in the Blackwell Companion to Philosophy, 2nd edition, edited by Nicholas Bunnin & E.P. Tsui-James, Blackwell Publishers Ltd, 2006.

McShea, D.W. & Brandon, R., Biology’s first law: the tendency for diversity and complexity to increase in evolutionary systems, Chicago: Chicago University Press, 2010.

Emergent properties

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storm over canyonPerhaps my strongest memory of being taught at school is that of the head of chemistry combining hydrogen and oxygen using an old glass drinks bottle and a burning taper.  The result was explosive, exciting and memorable.  It certainly engaged the attention of everyone in the class.  As far as I am aware, the demonstration was performed at least once per year for decades; but modern health and safety regulations would probably prevent such a demonstration today.

One of the interesting things about combining these two gases at room temperature is that the result is a liquid: water.  This could be construed as an emergent property because an examination of the properties of water would not lead you to predict that it was formed from two gases.  The philosopher C.D. Broad (1887-1971) coined the term ’emergent properties’ for those properties that emerge at a certain level of complexity but do not exist at lower levels.

Perhaps a better example of emergent properties is the pressure and temperature of steam.  We know that water molecules in a cloud of steam are whizzing around randomly,bouncing into one another and the walls of the container – this is the kinetic theory of gases.  If we add energy to the steam, for instance by heating it, then the molecules will gain kinetic energy and move around more quickly.  The properties of pressure and temperature emerge when we zoom out from the molecules and consider the system of the steam in a container.  The temperature of the steam is a measure of the average kinetic energy of the molecules and the pressure is the average force with which the molecules hit the walls of the container.

Manuel Delanda takes these ideas further in a brilliant description of modelling a thunderstorm in his book Philosophy and Simulation: The Emergence of Synthetic Reason.  There are no equations and it is written for the layman so don’t be put off by the title.  He explains that emergent properties can be established by elucidating the mechanisms that produce them at one scale and then these emergent properties become the components of a phenomenon at a much larger scale. This allows engineers to construct models that take for granted the existence of emergent properties at one scale to explain behaviour at another, so for example we don’t need to model molecular movement to predict heat transfer. This is termed ‘mechanism-independence’.

Ok, that’s deep enough for one post!  Except to mention that Capri & Luisi have proposed that life is an emergent property that is not present in the constituent parts of living things and which only appears when the parts are assembled.  Of course, it also disappears when you disassemble a living system, i.e. dissect it.

Sources:

Chapter 1 ‘The Storm in the Computer’ in Philosophy and Simulation: The Emergence of Synthetic Reason by Manuel Delanda, published by Continuum, London, 2011 (pages 7-21).

Fritjof Capra and Luigi Luisi, The Systems View of Life: A Unifying Vision, Cambridge University Press, 2014.