This posting is an additional part of the talk ‘Intelligence and the Brain’. Here, I tie together ideas from the talk about prediction with those concerning free will from the previous talk ‘Free Will/Free Wont’.
In a dualist worldview, the mind exists apart from matter and can be the seat of free will; it has no physical constraint. In a physicalist worldview, our behaviour is ultimately determined by the physics of the material world, via biology (I am saying nothing about consciousness here). Karl Friston’s ‘variational free energy’ theory provides a plausible account of how masses of neurons can behave in order to create the higher-level behaviour of the brain and so close the gap between the lower sciences (the traditionally ‘physical’ sciences: physics/chemistry/biology) and the higher sciences (the traditionally ‘non-physical’ sciences: psychology/ethology/sociology). In doing so, it would appear to leave no room for free will.
In the ‘Free Will/Free Won’t’ talk, the dualist concept of free will was replaced by the psychological concept of ‘conscious will’ (after Dan Wegner) and the physicalist concept of ‘freedom’. This notion of freedom introduced the idea that freedom is related to unpredictability and Shannon’s information theory, using as an example the humble fly’s erratic flight behaviour and our general inability to swat it as a result. In contrast, ‘Intelligence and the Brain’ is all about prediction. But predictability (from the standpoint of the agent) and unpredictability (from the standpoint outside of the agent – that is, of the environment) are really just two sides of the same coin. Previously, an analogy was made between predictive power and a hill. The higher up the hill, the greater the predictive power. But if there’s a downhill slope in a particular direction, there must be an uphill slope in the opposite direction!
- Downhill: An agent predicts its environment
- Uphill: An agent is unpredictable to the environment (it is difficult to predict uphill).
This gradient is what gives us our freedom.
The environment is difficult to predict because:
- It is complex. This is particularly true for organisms within it. It (and they) display chaotic behaviour.
- We cannot see inside those objects (agents) to see what is going on inside them.
The behaviour of those agents is very difficult to predict because they themselves embed their own predictive models of their environment, and hierarchically (at many levels) too.
So there are two problems for prediction (and hence our freedom) here:
- chaos (in the mathematical sense), and
- hidden states.
1 – Chaos:
Chaotic systems are one in which the behaviour is unpredictable even though the system is deterministic. Edward Lorenz defined it as:
“When the present determines the future, but the approximate present does not approximately determine the future.”
The classic example of a chaotic system is the double pendulum (see right; credit: Wikipedia). A single pendulum disturbed only slightly is so predictable it runs, literally, like clockwork. But a double pendulum that has been given a good swing, is a different animal. At times, most of the energy is in the outer pendulum and at other times, the outer pendulum just flops around, following the inner one. We cannot predict when transitions between these two types of motion will occur.
This is just with two arms – two degrees of freedom. Imagine how many there may be in the brain! The now familiar diagram of a hierarchy of predictors is a bit a like having many pendulums hanging off one another.
2 – Hidden States:
We cannot see inside the minds of others:
- We cannot read the minds of others (such as in the film ‘What Women Want’).
- We cannot monitor others by using instruments. The best instruments we currently have are large machines such as fMRI scanners. These, along with current knowledge, provide us with effectively no predictive information about the others at all. And they are not exactly inconspicuous!
(The former point is a dualist one; the latter is a physicalist one.)
Seeing inside another’s mind, hearing their thoughts or reading measurements of their brain scans – it doesn’t matter what sense might be used or whether it is internal or external. Our predictive power and our freedom would be considerably enhanced if we could access the states of others’ minds. And this is without a reciprocal arrangement; imagine the loss of freedom if others could read our minds.
Without any magical mechanism to see into the minds of others, we need to try to recreate what is going on the minds of other complex organisms by using our own brains.
Karl Friston provides a Free Energy example of recreating what is going on in the brains of others. That example is: how does one bird work out what another bird is communicating? This might seem trivial and very different from interpreting intentions of humans, but it is just a matter of scale.
A bird creates a sounds in its voicebox (syrinx) by chirping (which is itself a chaotic mechanism). A listening bird must decode that sound, to get beyond the physical details of the chirping sound, back to the source of that sound – the ‘decision’ to make one particular type of sound, rather than another. The listening bird needs to be able to discriminate between the different chirping which signify different things – to get beyond the body and lower brain levels and to hidden states within the singing bird.
Predicting inner (hidden) states of others is difficult but not impossible. In terms of the analogy of the hill (between freedom and the height of a hill), we can see the plateaus half-way up a neighbouring mountain from the vantage point of the top of our mountain. The taller our own mountain, the easier it is to see the mountains of others.
I have discussed the ability to predict a fly’s movement and to decode a bird’s song. But for us humans, it is generally far, far more difficult for an observer to predict our behaviour. In my analogy of prediction with height, these examples are like Silbury Hill to a human’s Mount Everest. We have privileged access to our own thoughts that others do not and we have some ability to getting inside the minds of others. It is the combination of these two things that give us our freedom.
That freedom does not need any random source. The chaotic complexity of our brains and small differences in our prior beliefs are enough to provide us will all the freedom we have.
Our freedom is large but finite. I have made the analogy with the hill and every hill is surmountable. In comparison, the dualist notion of mind separate from matter is analogous to a fantastically tall tower, impenetrable to anything the physical world might throw at it. But this is fantasy.