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.
