Sunday, October 14, 2012

The Causal Potency of Patterns: Hofstadter

Chapter Three of Hofstadter's I am a Strange Loop is called 'The Causal Potency of Patterns.'

There are quite a few important steps in this chapter. At stake is Hoftstadter's understanding of consciousness.

To develop a model of what happens in the brain we need to distinguish between different levels in reality. To develop this model  he proposes 'The Causal Potency of Collective Phenomena.'

Consider a traffic jam.  You are stuck in a traffic jam.  Why are you stuck?  One answer is that you are stuck because the car in front of you is barely moving.  Seen on this level, it is the car in front which causes the traffic jam!  You could easily be in a situation where you have no other knowledge as to the cause of the traffic jam other than the car you can see before you.

But what if you could step out of the traffic jam and see the situation from some other level?  From such a larger field of view there must be some other reason for the traffic jam other than car in front of you. Perhaps a blizzard or sports event has caused the jam.

The traffic jam metaphor allows us to understand the human brain in which many levels of causality operate.  Enjoying Chopin may not depend on any specific neuron in the brain being activated--such a neuron is only one of a whole community of neurons which is behaving in a way that only becomes clear from another vantage point which has to look beyond the behaviour of individual neurons.

It's not that there's a supernatural force at work; it's rather that what is significant isn't at the level of individual neurons. What counts is their collective behaviour and the explanation of this behaviour may not require a description of the behaviour of individaul neurons at all!

In the same way, when engineers consider the working of a combustion engine they do not worry about the behaviour of individual molecules, they concern themselves with pressure: "This high-level description of what happens is the only level of description that is relevant, because all the microdetails could be changed and exactly the same thing  . . . would happen (41).

Hoftstadter calls this phenomenon 'The Strange Irrelevance of Lower Levels.' If we focus exclusively on lower levels we become reductionist.  To a reductionist there are no boundaries: it's all the interaction of elementary particles.

Hofstadter challenges the explanatory power of the reductionist view with his story of the comet that smashed into Jupiter in 1993.  As the comet approached Jupiter some people on Earth became excited about the event: "There is no doubt that many months before the comet hit Jupiter, certain fender-benders took place on our planet that wouldn't have taken place if the comet hadn't been coming, certain babies were conceived that wouldn't have been conceived otherwise, certain flies were swatted, certain coffee cups were chipped, and so on' (47).  At a epiphenomenal level the comet impacted on our lives.

Concepts cannot be reduced to neurons.  Neurons are at one level--the level of cars in a jam or dominoes in a row arranged in a complex pattern--but concepts occur at a different level.  Concepts involve neurons but cannot be reduced to them.  In fact, concepts, analogies, metaphors operate at their own level. We can explain them without recourse to neurons at all!

I would add, here, that when it comes to the mind you can't see the wood for the trees!




No comments: