Emergent Phenomena and You

2 01 2010

The matter of the Chimpanzee and the matter of the stone are not so different...

Today I want to discuss something more philosophical than usual. This post contains personal thoughts that are not scientific and upon which there is not a consensus opinion. But I find the topic very, very interesting and I felt like sharing. So here we go.

The topic is Emergent Phenomena.

Let us start with a neuron.

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A neuron is a fantastic thing! It is a cell with many remarkable characteristics. In terms of its shape, the neuron is very long and spindly. It possesses long branches on either end of its body which allow it to interact with a multitude of neighboring neurons. On a molecular level, its membranes are studded with channels which permit ion flow into and out of the cell. These channels can be activated by a contact with certain molecules or by a sufficiently strong electric current. A neuron is certainly an amazing thing, yet if enough neurons are arranged together in a particular way, phenomena far more incredible emerge. Consciousness, emotion, thought, love, fear, anger, regret, joy, creativity, invention – all these are the product of neurons acting in concert. Yet if we examine the single neuron, we see nothing of any of these. Where is the consciousness in a neuron? What in a neuron accounts for love? What in a neuron accounts for the flash of insight that accompanies the conception of a great invention? Nothing! There is nothing in a single neuron that can account for any of these. Yet with sufficient numbers and a certain arrangement, these complex phenomena emerge. This is the idea of the emergent phenomenon – the thing which is greater than the sum of its parts.

The neuron itself – or more broadly the living cell – is also an emergent phenomenon. It is a living thing, comprised of nonliving molecules. How can this be? How can all the properties of life – mobility, reproduction, metabolism, adaptation, and so on – arise from molecules which have none of these? Again, it is the number, variety, and arrangement of the molecules which leads to the emergence of a new and more complex phenomenon.

Let us go deeper still. The molecules in a living cell are no mundane matter! They themselves are examples of emergent phenomena. Take an enzyme like lactase, which cleaves the milk sugar lactose into its constituent sugars, galactose and glucose. Lactase enzyme is a protein, a molecule comprised of many smaller molecules called amino acids. These amino acids are individually incapable of splitting lactase. Yet if you gather enough of them together in a specific order and structure, an enzyme emerges fit for the task.

We can go further still, to the atom! We have discussed water at great length on this site, and for good reason. If we examine oxygen and hydrogen, we see atoms comprised of nuclei and electrons, oxygen with its particular properties and hydrogen with its particular properties. But if you get them together, and pair two atoms of hydrogen to an atom of oxygen, you get a substance with many peculiar traits, among them cohesion, adhesion, a solid form less dense than its liquid form, a high specific heat, and so on. One would never expect all these remarkable traits simply by looking at the isolated oxygen or hydrogen atoms. Certainly, no one would predict such properties from the examination of a proton or electron! And yet here they are, molecules of inconceivable variety, each arising from a particular arrangement of protons, neutrons, and electrons.

I want to be careful to point out that for the emergent phenomena detailed above – consciousness, the cell, the enzyme, the molecule – the properties of the simple are not irrelevant to the properties of the emergent. They are in fact totally responsible for the properties of the emergent. Working our way from lowest to highest:

The properties of the water molecule are a result of the different electron arrangements of hydrogen and oxygen, as well as their relative electronegativities (affinity for electrons). These properties are in turn a result of the number of protons and neutrons in the nucleus of the atom.

The properties of the enzyme are a result of the interacting properties of the amino acids which compose it. One amino acid might contribute a negatively charged site to the molecule, another might contribute a positively charged site, while the pairing of a third and fourth amino acid might introduce a structural “kink” in the amino acid chain which brings the two in close proximity.

The properties of the cell are also a result of the interacting properties of the simpler things which compose it. In each cell there is a huge variety of large molecules which compose it.  The neuron’s ability to send messages depends entirely on the type and abundance of molecules which make it up. If it did not have the ion channels discussed above (themselves proteins like the enzyme lactase), it could not accomplish this feat. And of course, if it did not have nucleic acids like DNA to direct the synthesis of these molecules, it also would be incapable of performing its role in the body.

Lastly, the fantastic phenomena of the human mind are traceable to the properties of the neurons, and their ability to transmit signals rapidly among their kind.

So it is that emergent phenomena are entirely unexpected, but not entirely unexplained. We do not expect consciousness to arise from neurons, or neurons to arise from molecules, but once we see that they do, we can see why. Each level possesses properties whose interaction creates the properties of the next level. The interactions of the properties of that level in turn create the properties of the following level, and so on. Atomic structure determines chemical properties, which determine molecular structure, which determines molecular function, which determines cellular function, which finally determines organismal function. I want to emphasize that structure – the relative position of things in space – is of critical importance in understanding emergent phenomena. As I have mentioned, it is the interactions of the different properties at each level that determines the properties of the next level. For matter, and especially for larger molecules, the importance of structure cannot be overstated. For instance, in a protein, it is the arrangement in space of the amino acids which determines the function of the protein. Move one bit around, and it will no longer perform the same way. It’s function and its form are totally inseparable. Likewise, the particular properties of water depend on its being a molecule with a “bent” shape. If water was linear, with all three atoms in a row, it would not have its remarkable properties.

I wanted to write about this because I find it so interesting. Because it is so unintuitive to think that I, the breathing, thinking, moving, shouting, clapping me, am composed of simple atoms. How can this be! It baffles any attempt by the intuition – it appears that atomic structures and my love of singing, for instance, are totally irreconcilable! Yet this is not the case! The atomic structure of carbon is intimately tied to the good feeling I get when I sing. If we remove that piece, the whole thing collapses. Likewise I could hardly sing if I did not have hemoglobin, the molecule I rely on to transport oxygen and carbon dioxide around my body. And so while it seems absurd to attribute my love of singing to say, the atomic structure of oxygen, it is absolutely accurate, and if we carefully examine each level of emergence, it is not so hard to see.

There is some beauty that comes from this understanding. For example, this idea of emergence seems to erode the boundary between living and nonliving matter. The oxygen in me is no different in terms of its chemical properties from the oxygen in the atmosphere. Indeed, by the end of the day, many of the atoms in me now will be no longer, and many of the atoms previously “nonliving” – in the air I breathe or the water I drink – will be incorporated into this body, will be living. If we were to take this line of thinking further, we might raise serious questions about what it means for matter to be alive, or how to define a thing which is constantly in flux with its surroundings, or if it is even accurate to define an organism and the surrounding environment as separate things.

I am very interested to hear what others think of these ideas, as they are very intriguing to me. Please, comment at length!

Until next time,

Neil

Oh, and Happy New Year!

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