Emergence 2 – Mona Lisa

           I started exploring the idea of “emergence” in a previous entry <here>.  Emergence is the idea that something can have a property that doesn’t exist in its individual parts.  This could be the fluidity of water or the solidity of ice or even the color of ice.  But it could also be the properties of ant colonies that emerge when millions of ants work together and it could be the properties of societies when a large group of humans get together.  In fact, in some sense, anything that is not a fundamental principle could be considered an emergent property.  And, as I mentioned previously, probably the most interesting proposed example of an emergent property is consciousness.  “Consciousness as emergence” is the idea that when a complex network of neurons interact, consciousness emerges from that network even though it is not present in any one neuron. 

             In the first entry on this topic, I discussed the emergent property of meaning that arises from a collection of letters.  My contention was that the emergent property of meaning only exists in one place:  the conscious perception of an individual.  Thus, the “emergence” in this case can be boiled down to conscious perception and, in the end, the concept of emergence is exposed to be just another word for consciousness.  However, there is some disagreement about whether the meaning that emerges from letters is really the same as most commonly accepted examples of emergence, so it is necessary to dig deeper into this topic.

             Today I’d like to use what I think is a more commonly accepted example of emergence:  an image that emerges from a painting.  Let’s take the Mona Lisa painting by Leonardo da Vinci.  It is, at a molecular level, just a bunch of molecules spread over a canvas.  None of the molecules in the paint or even in the canvas have any resemblance to, or concept of, the image of Mona Lisa that we see when we look at the picture.  Thus, the image that we see can be said to be an emergent property of the painting or an emergent property of the molecules of paint that make up the image.  The sum of the paint molecules in the Mona Lisa is certainly greater than just the collection of paint molecules themselves.  There is something more there – something that emerges when the molecules are arranged carefully (by da Vinci) that could not have been predicted or expected by just examining the molecules of paint themselves.

             The question we want to consider is this:  where is the image of the Mona Lisa with respect to the painting?  Where does this emergent property exist?

             In order to explain the point I would like to make, I’m going to simplify the situation with some simplifying assumptions.  I don’t think any of these simplifications affect my conclusion, so please bear with the simplifications and then we can circle back and the end and consider whether the real complexity of the situation changes the conclusions I have drawn.

             First, I’m going to use a printed image of the Mona Lisa instead of the painting itself.  Specifically, a laser-printed image of the Mona Lisa.  Don’t worry – the image will be immediately recognizable when you look at the page.  But, if you were to greatly magnify the printed page, you would see that it is really just composed of a series of printed dots of different colors.  Each dot is a single color, based on the ink colors available in the printer.  We could go deeper in magnification and talk about the molecules that make up each dot, but that’s not necessary for the purposes of this thought experiment.  I think it will be obvious that the image of the Mona Lisa is not resident in the dots of different colored ink.  The dots themselves have no knowledge of what image they are a part of, obviously.  The printer itself was not given information about Mona Lisa – it was only given information about what color dots to print where.  But there is one thing for certain:  when we look at the page, we see Mona Lisa.

             Now I’m going to make a couple of major simplifying assumptions.  Let us imagine that there is a one-to-one match between the dots of colored ink on the paper and the photons of different color being reflected off of the page.  In this case, a single blue photon is reflected off of a single blue dot on the page and heads to your eye.  A single red photon is reflected off of a single red dot and heads to your eye.  At some given instant in time, all of the differently colored photons are reflected off of their respective dots and head to your eye.  If all of the photons were in sync with one another and timed just right, there would be a mass of colored photons heading toward your eye.  Each color and the location of each dot is preserved in that mass, or column, of photons.  Thus, in some way, you could slice that column of photons and get an image of the Mona Lisa.  But, of course, the photons, like the dots on the page, have no knowledge of the Mona Lisa.  They are just photons taking a specific color and existing in a specific point in space.  The emergent property of the image of the Mona Lisa is nowhere to be found in this collection of photons.

             This group of photons now enters your eye where they activate the rod and cone receptors in your retina.  My second simplifying assumption is that each photon actives a single cone cell, which then generates an action potential that travels along a single nerve fiber in the optic nerve.  Thus, there is a one-to-one correlation between the whole set of photons and the action potentials on multiple fibers in the optic nerve.  If the nerve fibers in the optic nerve preserved the geometric relationship of the cones in the retina, you could slice the nerve at some point and recreate the “digital image” of the Mona Lisa (after converting the action potentials to their indicated colors).  Again, that is an oversimplification for the purpose of this analogy.  The point is that the light image of the Mona Lisa lands on the retina and activates the appropriate cones, which send their signals along the optic nerve to the occipital cortex of the brain.  The parallel arrangement of the signals in the optic nerve are preserved, since each cone cell has a direct “single line” connection to the brain (due to my simplifications).

             The parallel signals along the optic nerve now enter the occipital cortex, where they kick off a complex neural network that extends around the visual cortex.  Some of one side of the image is split off and mixes with the other side.  Edges are identified.  Colors are identified.  The network of neural signals keeps expanding to different areas of the brain.  Memory is activated and the image is compared to past knowledge and things we recognize from our past.  All of this happens pretty quickly because it doesn’t take us long to glance at the picture of Mona Lisa before we recognize it as being Mona Lisa.

             Some might think that eventually these neural signals end up activating some single neuron in the brain that only lights up when you look at a picture of Mona Lisa.  That is sometimes referred to as the “grandmother cell hypothesis” though I’m not sure that was ever a serious scientific idea.  But there is no such single neuron.  Instead, the collective activity of the neural networks across the brain give rise to the general awareness, and thus conscious perception, of Mona Lisa.

             My contention is that, until this final step of consciousness, there is no place for any emergence of the image of Mona Lisa.  In this whole process, from the dots on the page, through the light transmission, to the neural activity - all the way to the brain – there is no place where the information is brought together into a cohesive “image of Mona Lisa”.  It doesn’t happen until it happens in our brain and we have the conscious recognition of “oh – that’s the Mona Lisa.” 

             It is reasonable to wonder whether my simplifications resulted in my “factoring out” emergence from what really happens.  Of course the whole process is much more complex.  Lots of photons are bouncing off of each dot on the page and heading to the eye, not a single photon.  They are coming at different angles, different colors, etc.  But photons stay as photons – they don’t mix together to create a cohesive image – so I don’t think anyone would claim that the emergence of the image of Mona Lisa arises from the reflection or travelling of photons from the dots on the page.  However, once the photons get to the rods and cones in the retina, the processing is certainly a lot more complex than my simplification.  There are ganglion cells in the retina and some pretty complex processing happens even just between the cones/rods and the ganglion cells.  My argument here is that the processing in the eye is just an extension of the processing that is carried on in the visual cortex.  It can all be lumped under the category of neural processing in the “brain” and, in fact, the retina is considered part of the central nervous system.  Thus somewhere, somehow, the image of Mona Lisa arises from the neural processing in our brain (or central nervous system, if you prefer).  The emergent property of the image – the Mona Lisa - does not exist until we consciously perceive it.  My contention is that every example of emergence (at least every example of “weak emergence”) boils down to this same conclusion:  the “emergent property” only emerges in our conscious perception of it, and nowhere else.

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             I imagine a discussion with someone about how it is that consciousness just arises from the neural activity from the brain.  I would maintain that consciousness is non-material [see here], whereas they would maintain that consciousness is purely a physical thing that naturally arises from the action of neurons.

             “If consciousness is purely a physical process, what is the means by which it just arises from neural activity?” I would ask.

             “Consciousness is just an emergent property that naturally arises from the activity of neurons, just like many other emergent properties of material objects.”

             “An emergent property?  What does that mean???  Could you give me an example of an emergent property outside of consciousness itself?”

             “Well, for example, imagine you’re looking at the painting of the Mona Lisa…”

Emergence 1 – My Contention

             I want to explore the idea of “emergence” or “emergent properties”, as I understand the philosophical concept.  Emergence is probably more popularly summed up in the common phrase “The whole is greater than the sum of its parts.”  Emergence is the idea that something can have a property that doesn’t exist in its individual parts.  I think the most common example typically put forth as an emergent property is the “wetness” or “fluidity” of water.  Water is just a collection of H2O molecules.  An H2O molecule has no property, by itself, that could be called wetness.  But when you put a bunch of them together (and the temperature and pressure are right), the property of wetness “emerges” out of the collection of molecules, and thus it is considered an emergent property.  An emergent property is also frequently defined as a property that you would not (or could not?) have predicted by just looking at the individual parts.  The idea of emergent properties is apparent in everything from molecules to societies.

             There are lots of examples of emergent properties, and I will explore some in future entries.  However, there is really only one so-called emergent property that I care about:  consciousness.  How consciousness is related to the actions of a bunch of neurons communicating with one another is of great interest to me.  There are many people who consider consciousness to be the quintessential example of an emergent property.  They say that consciousness is a property that naturally arises from the complex interaction of neural networks.  This allows them to consider consciousness to be a natural part of the material world – as natural as the wetness of water - and nothing more.  Importantly, this allows them to reject any idea that consciousness is non-material or immaterial.  I think that is a mistake (see here and here), and I hope to show why I say that over the course of a few thought experiments that I will initiate with this blog entry.  My contention is this:  calling consciousness an emergent property of the brain is tantamount to saying that “consciousness is the property of exhibiting consciousness” …which is no explanation at all.  Further, I want to make the contention that all “emergent properties” are conscious perceptions.  I contend that “emergence” and “consciousness” are the same things, and so you can’t use one to explain the other, because all you are saying is “consciousness is consciousness.” 

             This is a tricky argument for me to explain, so I’m going to unravel it slowly, hoping that what I say makes sense.  This is my first time trying to explain this concept, so it may be a bit rocky.  I would certainly be interested in people’s comments on the matter.

             I’m going to start my series of thought experiments about emergent properties by using an example that I have to admit is marginally “emergent”:  specifically, the meaning of words.  If we string together a couple of “A”s, a couple of “I”s and an “L”, “M” and “V” in the right order, we can create a meaning that emerges from those letters that is certainly not contained in any single letter and could not be predicted by examining the letters alone.  We could string those letters together to create the phrase “I AM ALIVE”, which has a very significant meaning that has nothing to do with the letters themselves.  The meaning of the phrase could be considered an emergent property of those letters.

             My question now is this:  where does the emergent property of those letters exist?  Does it exist on the page (or screen) where those letters appear?  Does the emergent property somehow float above the letters in some way?  This is obviously not the case.  If an ant crawls across the page, it doesn’t encounter the meaning of the phrase encompassed by the letters.  If a bird flies overhead and sees the entire phrase, it doesn’t encounter the emergent property of the meaning of the phrase.  In fact, if a non-English speaking person, or an illiterate person, looks at the entire phrase, they also will not experience the emergent property of these letters.  The only one who experiences it is an individual who knows the meaning of the phrase as it is written.  Thus, the emergent property exists only in the minds of human beings.  Further, it exists only in the minds of some human beings.  Thus, since not all seeing humans experience the meaning of the phrase, I think it should be clear that the emergent property does not exist in the visual perception of the words or even in the visual cortex.  Two different people can look at the phrase and see exactly the same image in their brains, but one experiences the meaning and the other, who doesn’t know English, experiences nothing.  In fact, it is not until the firing of various neurons in our brain are brought together into our conscious perception of the fact that the image we see on the page is actually a phrase, and the phrase means something, that we experience the emergent property of meaning.  Thus, in this example, the emergent property of the meaning of the phrase is our conscious perception of it.  The emergent property just is conscious perception, in this case.  If we then say that the meaning of letters is an emergent property, we have not found a new property at all.  All we are describing is our conscious perception of the meaning.  We initially ascribed the emergent property to the letters themselves, but that’s not where the emergent property exists.  It exists nowhere but in our consciousness.  It just is our consciousness.  There is no difference between the emergent property of “meaning” and the conscious perception of meaning.  I hope that makes sense.

             If the meaning of words were a clear example of what people call an emergent property, then I might be able to rest my case with this one example.  But calling the meaning of words an emergent property is not particularly clear.  Most “true” emergent properties spontaneously arise from the collection of their parts.  The meaning of words does not naturally arise from their existence.  Meaning also requires a set of rules of language, rules that have to also be understood and agreed on by others who use the same language.  For the words to have the meaning they have, there are a lot of outside things that have to be brought to bear upon the series of vertical, horizontal, and slanted lines that make up the phrase “I AM ALIVE”.  Given that, I don’t think most people would consider “meaning” to be an emergent property in the same way that “wetness” is an emergent property.  I’m not sure I totally agree with that, since it seems to me that if you consider the parts of your system to be the letters plus the linguistic rules of English, then you can still say that meaning emerges from the sum of the parts, it’s just that the parts are a lot more complex.  But I’m not going to argue that here.

             In summary, to the extent that the property of “meaning” is an emergent property of letters, the concept of emergence is shown to simply be a restatement of the property of consciousness.  They are one and the same.  The idea of meaning itself cannot exist without consciousness.  My goal is to show that the same thought process can be applied to more standard examples of emergence and that the same conclusions can be drawn.