Emergence 3 - Wetness of Water

               A while back, I started exploring the idea of “emergence” in a previous entry <here> and then again <here>.  Emergence is the idea that something can have a property that doesn’t exist in its individual parts and wouldn’t have been anticipated just by observing the parts themselves.  I’m interested in the idea of emergence because it is so commonly used as a possible explanation of how consciousness arises from a network of neurons in the brain.  “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.  My contention is that, when you really analyze what emergence is, it is actually just another word for consciousness.  If my contention is correct, then saying that consciousness is an emergent property of the brain is the same as saying “consciousness is consciousness”, which, of course, explains nothing.

              So far, I’ve talked about the meaning of words that emerge from various arrangements of letters, and the image of a picture that emerges from a painting (example:  Mona Lisa).  In both cases, the “emergent property” was shown to be equivalent to the conscious perception of that property.  However, it seems to me that there is a lot of disagreement about what constitutes an emergent property, so I’m not sure my first two examples are sufficient to establish my contention.

              Therefore, today I’m going to address the property of “wetness” that emerges when a bunch of water molecules get together at the right temperature and pressure.  The molecules themselves could not be described as being wet, yet the property of wetness emerges from the collection of them.  I think this is pretty much the quintessential example of an emergent property, which I expect is due to the use of this example by the late philosopher John Searle.  Searle is probably best known for his “Chinese Room” analogy of consciousness.  In my opinion, Searle is one of those people you enjoy listening to even when you don’t agree with them!  Here’s how he used the emergent property of the wetness of water in his arguments:

 “All of our conscious states, without exception, are caused by lower level neurobiological processes in the brain, and they are realized in the brain as higher level, or system features. It’s about as mysterious as the liquidity of water, right? The liquidity is not an extra juice squirted out by the H₂O molecules, it’s a condition that the system is in; and just as the jar full of water can go from a liquid to solid, depending on the behavior of the molecules, so your brain can go from a state of being conscious to a state of being unconscious, depending on the behavior of the molecules.” — John Searle

               I don’t think anyone would argue that the wetness or liquidity of water is not an example of an emergent property (except for those who don’t think there are any emergent properties at all).  Thus, if I could apply my previous reasoning regarding words and paintings and show that the emergence of wetness is just conscious perception, then I think I would have a strong argument to generalize to “all” emergent properties (until someone can show a property that breaks the rule).  However, it’s not that easy in this case, and that’s because the idea of “wetness” or “liquidity” has multiple aspects to it.

               There are at least three aspects to what we mean when we talk about the wetness of water that I will need to address.  I’m going to address the easy one in this entry, and address the other two in future entries because they have broader implications to this discussion.  But let me introduce the three aspects here so you can see where I’m going.  First, wetness can refer to the sensation that we feel when we touch something wet.  There is “something that it is like” to touch something wet.  Second – and here the term “liquidity” or “liquid” is generally used – wetness can refer to the fact that the water is in a state of being a liquid with all of the properties that flow (literally) from being a liquid.  The third aspect is that the “wetness” of water is a measurable property.  Soapy water, for example, is “wetter” than pure water and has properties that can be objectively measured to demonstrate the degree of wetness.  Thus, surely, if I can independently measure a property, I can’t claim that it is “all in our mind” can I?  That will be a discussion for the future.

               In this entry, I’m taking the first instance where wetness refers to the way wet things feel.  When we touch something wet, there is a way that feels to us that is instantly recognizable from touching something solid.  Often, we can “see” wetness as well because of the way light shines off of something that is wet, though we can also be fooled by, say, a very high gloss solid surface.  The point is that when we are talking about this instance of wetness, we are talking about a sensation that we feel through our hands or wherever it is that we are touching something wet.

               If you’ve read through my first two entries on this topic, then what I say here should be very familiar and not surprising.  In this case, feeling the wetness of water is directly analogous to seeing the Mona Lisa in a painting – it’s just a different sensory modality.  Given that, we can follow the same path and ask ourselves “where does the wetness exist?”

               In the case of wetness as I’ve defined it, we can easily see that wetness does not exist in the water itself.  That’s because I’m focusing on wetness as a sensation.  The water molecules themselves do not “feel” anything (though they do experience forces from other water molecules – something we’ll have to address in the next entry).  So, when we describe the sensation of wetness, we are clearly talking about something that happens to us when we feel something wet.  Where does that sensation of wetness “reside”?  When we touch a wet surface, the water molecules must interact without our touch sensing organs in our fingertips.  Maybe the Merkel cells or Meissner’s corpuscles are activated in a certain pattern.  I’m going to make a guess that a single water molecule is not enough to activate one of these sensory endings.  Wetness, it would seem, almost certainly requires the activation of multiple sensory endings in a certain pattern.  I’m not sure what that pattern is exactly, but it would surely be spread out among an area of skin, sending an array of action potentials back to the brain.  Although there would likely be some processing of these signals in the dorsal root ganglion and maybe spinal cord, nowhere in the transmission of these signals is there a single cell that lights up to indicate the sensation of wetness.  This is completely analogous to the discussion of seeing the Mona Lisa.  There is nothing in the transmission itself that indicates the perception of the emergent property we are discussing. 

               Ultimately, as before, the sensation of wetness never even coalesces in the neurons in our brain.  There is processing of the sensory signals for sure, but there is not a single “endpoint” neuron that lights up with a little display that flashes “wet, wet, wet” to indicate the sensation of wetness has been perceived.  Instead, it is our conscious perception of wetness that is the “endpoint” of this process.  Thus, as we have found with other emergent properties, the emergent property of wetness just is the conscious perception of wetness.  Emergence is consciousness.  Emergence, in this case, isn’t analogous to consciousness.  They are the same thing.

               I acknowledge that this entry is not a particularly deep argument.  By focusing on the sensation of wetness, I’ve basically asked “where is the conscious perception of wetness?” and then answered that it is in our consciousness.  It’s kind of obvious.  But I’ve come across some authors on the topic of consciousness who don’t seem to recognize this obvious link, and so I felt it was necessary to spend a bit of time on this.

              What is more interesting is the question of the second and third aspects of wetness.  Can these be considered emergent properties?  And, if so, surely they do not reside solely in our consciousness, do they?  We’ll address those issues next.