Neuroscience, free will and determinism: 'I'm just a machine'
- Neuroscience, free will and determinism: 'I'm just a machine'
Our bodies can be controlled by outside forces
in the universe, discovers Tom Chivers. So where does that leave free will?
For a man who thinks he's a robot, Professor
Patrick Haggard is remarkably cheerful about it.
"We certainly don't have free will," says the
leading British neuroscientist. "Not in the sense
we think." It's quite a way to start an interview.
We're in the Institute for Cognitive Neuroscience,
in Queen Square in London, the nerve centre
if you will of British brain research. Prof Haggard is demonstrating "transcranial magnetic stimulation",
a technique that uses magnetic coils to affect
one's brain, and then to control the body. One
of his research assistants, Christina Fuentes,
is holding a loop-shaped paddle next to his
head, moving it fractionally. "If we get it right,
it might cause something." She presses a switch,
and the coil activates with a click. Prof Haggard's
hand twitches. "It's not me doing that," he assures
me, "it's her."
The machinery can't force Prof Haggard to do
anything really complicated "You can't make
me sign my name," he says, almost ruefully
but at one point, Christina is able to waggle
his index finger slightly, like a schoolmaster.
It's very fine control, a part of the brain
specifically in command of a part of the body.
"There's quite a detailed map of the brain's
wiring to the body that you can build," he tells me.
I watch as Christina controls Prof Haggard's
fingers like a marionette. The mechanical nature
of it is unsettling. A graph on a screen shows
his muscle activity plotted by time; 20 milliseconds
after she clicks the button, it depicts an elegant
leap and drop, like a heartbeat on an ECG. That
20 milliseconds is how long it takes for the
signal to travel down his nerves. "The conduction
time would be less from my jaw muscles, more from
my leg muscles," he says. And as many of us will
recognise, the process gets less effective as
we age: "As I get older, the curve will move slowly
to the right on the graph."
The idea that our bodies can be controlled by an
outside force is a pretty astonishing one. "This
is absolutely out of my control," insists
Prof Haggard, as his muscles continue to move.
"I'm not doing it, Christina is. I'm just a machine,
and she is operating me."
What does this mean in terms of free will? "We don't
have free will, in the spiritual sense. What you're
seeing is the last output stage of a machine. There
are lots of things that happen before this stage
plans, goals, learning and those are the reasons
we do more interesting things than just waggle fingers.
But there's no ghost in the machine."
The conclusions are shocking: if we are part of
the universe, and obey its laws, it's hard to see
where free will comes into it. What we think of as
freedom, he says, is a product of complexity.
"An amoeba has one input, one output. If you touch
it with one chemical, it engulfs it; with another,
"If you see a light go green, it may mean press
the accelerator; but there are lots of situations
where it doesn't mean that: if the car in front
hasn't moved, for example. The same stimulus sometimes
makes me press the accelerator, but sometimes the
horn. We are not one output-one input beings; we have
to cope with a messy world of inputs, an enormous
range of outputs. I think the term 'free will'
refers to the complexity of that arrangement."
Slowly, however, we are learning more about the
details of that complexity. This, Prof Haggard
says, has profound implications: philosophically,
morally, and most worryingly legally. "We understand
what brain areas are responsible for impulsive
behaviour, and which bits are responsible for
inhibiting that behaviour. There's a whole brain
network associated with holding back from things you shouldn't do.
"What happens if someone commits a crime, and it
turns out that there's a lesion in that brain
area? Is that person responsible? Is the damage
to the machine sufficient for us to exempt them from
that very basic human idea that we are responsible
for our actions? I don't know." He refers to a major
project in America, where "lawyers, neuroscientists,
philosophers and psychiatrists are all trying to work
out what impact brain science has on our socio-legal
sense of responsibility".
This runs shockingly contrary to the sense of freedom
that we feel in terms of controlling our actions,
on which we base our whole sense of self and system
of morality. "As far as I know," says Prof Haggard,
"all societies hold individuals responsible for their
actions. Even in animal societies, individuals have
reputations. Non-human primates adjust their behaviour
according to how other animals will respond. Junior
males will not steal from older males, because they
know they'll get beaten up. That's the beginning of
social responsibility; the awareness that your behaviour
has effects on the behaviour of others, and can have
good or bad consequences.
"It's a rule that we need to have as social animals.
You couldn't have society unless, if you do something
wrong, you pay for it. The question is, what do we
do when people don't have the brain machinery to play
by the rules or decide not to play by them? That's
not a scientific question. That's a moral one."
Maybe, I suggest, we've over-defined free will.
Perhaps it doesn't exist in the mystical
breaking-the-laws-of-the-universe way, but there
is a sense in which this "me", this brain and body,
responds to the world, reacts to information, tries
to shape its environment; takes decisions. Can we
not pull free will back to something more defensible?
He taps his fingers.
"Yes, interacting intelligently with your environment
might be enough. The philosophical definition of free
will uses the phrase 'could have done otherwise'.
I picked up the blue cup; could I have picked up the
white one? Given the initial conditions, the world
as it was, could I have acted differently?
"As a neuroscientist, you've got to be a determinist.
There are physical laws, which the electrical and
chemical events in the brain obey. Under identical
circumstances, you couldn't have done otherwise;
there's no 'I' which can say 'I want to do otherwise'.
It's richness of the action that you do make, acting
smart rather than acting dumb, which is free will."
Some philosophers Robert Kane, and, famously,
Karl Popper and John Eccles have held out hope
that quantum indeterminacy, the randomness at the
level of the universe's finest grains, could
rescue true freedom.
Prof Haggard is dismissive. "No one wants to be
told they're just a machine. But there is simply
nothing approaching convincing evidence for the
quantum view. Popper and Eccles proposed that free
will was due to quantum indeterminacy in the
chemical messages that communicate between neurons.
"But none of that happens at the quantum level.
From a physics point of view, it's macro-level."
Besides, quantum activity is purely random, and
randomness gives you no more freedom than determinism does.
Does this bother you, I ask? Being a machine?
"I keep my personal and professional lives pretty
separate," he says, smiling. "I still seem to decide
what films I go to see, I don't feel it's
predestined, though it must be determined somewhere in my brain.
"There's an idea in theology that our free
will places us next to God. Milton describes
this beautifully in Paradise Lost. We like to
think we're wonderful, that we have this marvellous
capacity. But we should be more impartial: perhaps
we overestimate the value and the excitement of
having free will."
On that note, I take my leave. Although really,
I didn't have any choice.
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