Non-reductive Physicalism and Conway’s Game of Life
When you reach out to grab your cup of coffee, what is causing this action? Is there a special internal ‘you’ somewhere in there pulling the levers? If so, what is this ‘you’ made of and how does it cause these limbs of meat and bone to move? Or do you believe that you are merely a big heap of atoms, nothing more? How then do mere atoms ‘want’ to grab a cup of coffee?
These are some of the kinds of questions that rear their heads when we start to think about our ‘minds’; who ‘you’ are, what ‘you’ are made of and what our relationship is with the world around us. How is the mind different from the brain?
For a very long time a common view was held (and is still held by some people today) that ‘we’ are a non-physical essence or soul linked in some way to our physical brains — this is called ‘dualism’ because you believe in two types of ‘stuff’ — and this essence is able somehow to cause our brains and therefore our bodies to do things. But this concept is riddled with problems and I’m not going to go into them here suffice to say that very few people who’ve taken an interest in any kind of science of the mind would hold to it.
But in the absence of this non-physical explanation and in the light of the mounting evidence for the brain merely being ‘what the brain does’ we’re left in a bit of an awkward situation. How can mere atoms be emotionally moved by a song? How can bags of chemicals build a car? These kinds of questions become especially difficult when you happen to believe that the universe is such that there is a supreme being out there who has a purpose for you and yet you find dualism decidedly uncompelling. Reductive physicalism (i.e. a world which is only made of physical things that can be explained by describing the smallest parts) doesn’t really seem to have a place for a supreme, purposeful being.
A solution may be at hand however. What if we accept that, yes, atoms do clump together to form molecules and molecules clump together to form organisms that can act in their environment all in a kind of a ‘bottom-up’ path of causation. But then we will notice that things such as natural selection can themselves emerge and have a kind of a ‘top-down’ causation that, in turn, affects and improves these critters that have been produced purely by the actions of atoms. This gives us a way to view the world in the light of the best available evidence (i.e. we can have just atoms and we can include the power of natural selection and so on) at the same time as breaking away from the disconcerting concept of a world in which everything is driven by the mere mindless jiggling of atoms. This is called ‘non-reductive physicalism’ because we admit that we’re made of ordinary matter but the rules that guide atoms are not enough on their own to get us to where we currently are.
I think I spotted a flaw in this logic but in order to effectively illustrate what the error is I’m going to have to go off on a tangent and discuss a geeky bit of software called Conway’s Game of Life.
Conway’s Game of Life was created back in 1970 by mathematician John Horton Conway. In essence it’s a grid of blocks that can be either alive (black) or dead (white) in which each block conforms to four simple rules:
- If you’re alive and have one or less alive neighbours, you’ll die
- If you’re alive and have two or three alive neighbours, you’ll survive
- If you’re alive and have more than three alive neighbours, you’ll die
- If you’re dead and have three alive neighbours you’ll become alive
Using these four simple rules if you start off with a pattern of three dots selected one above the other like an ‘l’ you will find that the top and bottom dots will die (become white) because they each only have one neighbour. The middle dot will remain because it has two neighbours. The empty dots to the left and right of the middle dot will come alive because they both have exactly three alive neighbours. Once this has been calculated the grid is redrawn and you’ll notice that we now have three dots again but this time they’re side-by-side like a dash. If we apply these same rules again we’ll end up with the same configuration that we started with and so on and so on. Not really all that interesting but it’s a start.
There are many different configurations possible. Some of them remain static, some blink like the example above, some bloom out into endless randomness or collapse into a detritus of blinking and static objects. Some that have captured the imagination of many can even ‘travel’ across the screen endlessly or even generate repetitive patterns. See the image on the right for an example of one of the most common travelling objects called a ‘Glider’. See how it obeys the four rules and yet seems to have transcended them in some way. It now seems to have some additional rules like “move on a diagonal down the page and to the right”.
Here, have a play with this one online but please come back to see how this all relates to the seeming conundrum of minds, bodies and non-reductive physicalism.
Even more complex, see the example on the right of a ‘Gun’ which produces an endless stream of gliders. Now we can’t help but lose track of our four simple rules and we’re now seeing actual entities interacting with each other in a seeming causal manner. The gun has got two stopping/absorbing blocks with a couple of arrow-things that fly back and forward between them producing a stream of gliders which move diagonally away from the gun.
Can you see where this is going yet?
What we’re doing — albeit at a simplified level — is we’ve acknowledged that four simple rules can create some interesting patterns and then we’ve started thinking about the movements of the patterns themselves in a way that doesn’t seem to need to account for the four rules any more and, if we aren’t too careful, we might be tempted to think that the four rules weren’t sufficient to describe a ‘Gun’ that ‘produces’ ‘Gliders’.
This is exactly what I see happening when people posit non-reductive physicalism. As with Conway’s Game of Life where I can show you just enough yet be able to drag you back to admitting that, yes, these four simple rules are up to the task of producing what we perceive as guns and gliders so it is with the power of atoms to use a very simple set of rules (i.e. varying degrees of attraction/repulsion/jiggliness and so on) to produce molecules, chemicals and organisms which interact with each other. And to even provide us with brains in which to build mental constructs — which are themselves purely physical — of things such as glider factories and natural selection).
Non-reductive physicalism can be fairly described as “the idea that while mental states are caused by physical states they are not reducible to physical properties”. But what I think they are really saying is “In order for us to understand mental states, we can’t do it just by looking at the atoms that make them up”. Which, to me is exactly the same as saying “while glider guns are caused by the four rules they are not reducible to those rules” or, “In order for us to understand the behaviour of glider guns, we can’t do it just by looking at the the four rules”. But this speaks more to how our limited physical minds operate and how we require the use of analogies within analogies in order to form predictions and descriptions about the world. Not to how the world really is.
[The three images above are all sourced from the Wikipedia page on Conway's Game of Life. The Glider Gun image was created by Kieff.]
Great post! I love cellular automata like the game of life (there is an evolutionary equivalent called sugarscape which is very cool) and have read dozens of books covering complexity theory which is closely linked to your post and feel it really is an eye opener.
Once you break the mental correlation between the complexity of the make up of a system and the complexity of its behaviour you can make quite a bit more sense of the world imo
tres interessant.
I really must find time to read Nancey Murphey’s chapter in a book I’ve got called ‘Personal Identity in Theological Perspective’. Her chapter is called, ‘Nonreductive Physicalism: Philosophical Challenges’ and takes a positive view of non-red. phys (NRP). There’s a vid here, and some articles can be found via google (as always!). For her, NRP is fully compatible with her Christian belief. The thrust of it, would be (from my limited interaction) that human ‘soul’ or ‘spirit’ doesn’t need to be a distinct ‘substance’; God remains ontologically distinct from creation (whatever its make-up) and can act upon it, relate to it, etc.
As for your post, I was wondering if you could help me to see the correspondence of the Game of Life and actual biological life. It seems that the use of the word ‘life’ in the title (and ‘dead’/'living’ in the four rules) is a bit sneaky? It could just as easily be called the game of colour, or the came of filling (boxes), or the game of on (and off), etc. The first three rules would be easy enough to relate to the notion of survival (over-crowdedness and over-isolatedness seem to lessen survival), but the fourth rule!!?? re-vival!?
((I’m amen-able to having a beer/coffee, FYI.))
Hi Dale,
Yes, it was Nancey’s work on top-down causation (via Glenn People’s excellent podcast series on the mind/body problem) that led me to address this topic.
The Game of Life for the purposes of this post doesn’t need to have any relationship to real life. The point was to show how we (or, our brains) are happy to start with a reductionist view — i.e. the ‘four rules’ — and very quickly succumb to analogies such as ‘guns’ and ‘gliders’ in a way that tempts us to question how something as simple as four rules could possibly account for the analogies we utilise to understand the bigger picture. We can all agree (I hope) that a glider is no more than the four rules in action and that the it’s really no more than a concept constructed by our brains. But we can all see (again, I hope) just how close we were to thinking that the analogy of a glider or a gun could not possibly be reduced to four rules. i.e. where in the four rules do we get “moving diagonally down the page”?
There *is* such a thing as a game-of-life-glider but it’s in our heads. In reality there were just pixels turning on and off. Similarly, there *is* such a thing as real-life-natural-selection but it’s in our heads. In reality it’s just atoms obeying the laws of physics. [*edit*] Nancey seems to think that natural selection is a real thing out there in the world which has a top-down causation on the atoms below. She would have to also admit that there were real guns in Conway’s Game of Life that had a top-down causation on the state of the pixels when they created gliders and that were not reducible to the four rules. I’m not sure she’d be prepared to do that.
As an aside, and to further complicate things, atoms and ‘laws of physics’ are probably further reducible which raises the interesting question of whether our brains could ever possibly see reality for what it really is. I somehow doubt it.
Ian, I had a look at SugarScape. Thanks, I’d never come across that before. I’d be interested to see a list of your recommended reading on complexity theory. The only books that I’ve read that have touched on the topic are Deep Simplicity by Gribbin (which I really should re-read because I held very different beliefs at the time), Freedom Evolves by Dennett and Consciousness: An Introduction by Blackmore.
I’m confused – are you saying…
lawful boxes –>> ‘objects’ (‘gliders’) & ‘movement’ (‘down+right’)
and so also…
lawful atoms (brain matter) –>> ‘thoughts’ & ‘mind’
if so, what would be a similar analysis for natural selection? something like…
lawful physics –>> ‘evolution’ (‘natural selection’)???
…because it seems to me that such a view could still even be dualistic (of the emergent variety). One substance gives rise to another.
Indeed, if it is truly ‘non-reductive’, then it cannot rule out (reduce) the ‘other substance’ in terms of the one?
I’m not really sure what you mean by ‘lawful’? And I’m not really sure I understand any of the second comment. (are you thinking that I’m arguing *for* non-reductive physicalism??)
‘lawful’ just means ‘the boxes (or atoms) behave according to the four (or natural) laws’
(And I’m not sure if you are arguing ‘for’ NRP or not – it appeared you were?)
Ha! No, I tried to present top-down causation (or non-reductive physicalism) as a potential middle ground between dualism and brute physicalism in an attempt to best represent the arguments made by the likes of Nancey and then proceeded to show how this top-down causation is merely an artefact of the way our brains work with the example of the seemingly non-reductive objects we construct in Conway’s Game of Life.
I apologise for any confusion. Obviously not as concise an argument as I’d hoped to make it.
Gribbin is an excellent one. I’d also recommend the following which are either directly on complexity or help build up the picture around it:
Mitchel Waldrop – Complexity
Mark Ward – Universality
Jeffrey Kluger – Simplexity
Eric Beinhocker – The Origin of Wealth
Stuart Kauffman – At Home in the Universe
John Holland – Emergence
Stephen Wolfram – A New Kind of Science
Peter Coveney & Roger Highfield – Frontiers of Complexity
Ilya Prigogine & Isabelle Stengers – Order out of Chaos
James Gleick – Chaos
Benoit Mandelbrot – The (Mis)behaviour of Markets
Thanks for that Ian
@Dale: I think the point of the word “life” in the GoL ss that lifelike behaviour appears out of something that intuition tells you it probably shouldn’t. It is also a reflection of how it took on a life of its own with people developing their own “lifeforms” and concepts within it.
Another interesting fact is that the GoL is what is known as a “universal cellular automata” which is to say that it is capable of performing the same basic set of calculations that a computer can, or in other words a large enough and clever enough arrangement of the initial conditions could in principle run the internet (abeit woefully inefficiently). I’m not entirely sure the relevance of that now I mention it but it probably shows up that I’m an enthusiast lol!
Ian. Sure, there are appearances, etc. but if you don’t want apologists to say, “but who wrote the laws?” or “but who selected just the right initial conditions?” you might want to hold the analogy loosely!?
There is a danger of taking any analogy too far but the cool thing about this one is that it is also a working model demonstrating a couple of powerful points:
1. Simple systems can produce complex outcomes; and
2. If you can only see the world at some meta-level (e.g. the level of gliders) a deep understanding is extremely difficult.
my (can’t help myself) version of your two points:
1) If the system is just right, simple/small mechanisms/events can produce complex/large results.
2) If you pan-out the micro-level in place of the macro-level, you (obviously) won’t see or understand the micro-level!
lol – I half agree:
1. There is a broad range of cellular automata that produce behaviour far exceeding expectations including much simpler 1D CA models (GoL is a 2D CA) that are also universal. Incidentally the universality issue is far more significant than “looks lifelike” issue which makes GoL fun as well as in instructive
2. For sure but it is more than an issue of scale – the nature of the phenomena at different scales can be entirely different as well. Also I think we see the world at a level analogous to gliders, even at the sub-atomic level.
1) yeah, with the right system, amazing things can happen!
2) hear hear!
The “right” system isn’t all that hard to find either which I suppose is the real key – in 1D 2 state 2 neighbour CAs (GoL is a 2D 2 state 8 neighbour CA) there are 256 possible rule sets of which 17 (or 6%) display non-trivial behaviour (of which at least one, and potentially as many as 7, exhibit universality). That’s a very large proportion in the grand scheme of things.
ain’t none of ‘em without a heckuva lotta carefully placed ones and zeros tho
It’s a much more general principal than that