If you’ve seen my videos before, then you know that one of the subjects
I’m obsessed with is free will. I’ve mainly talked about human free
will. But if we have free will, shouldn’t all creatures also have
free will, even simple creatures?
The question I want to know is how low in
complexity can you go and still have free will. Does a bacterium have free
will? Do single cells have it? It turns out that although
biological systems can’t break the laws of physics, they seem to
construct some laws of their own. They might not have free will,
exactly, but they have an ability to make changes that suit themselves.
In other words, they have agency.
Animals seem to do whatever they damn well
please. Is there a method to the madness? Is there a driving force for their actions? What do we know about agency in living
systems? That’s coming up right now… If you like today’s subject, then you’re going
to love a documentary I saw on Magellan TV, today’s sponsor, called, "Life on Us." It’s
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For this episode, I collaborated with someone
with a lot more expertise on this subject than me, and whom I think you’re really
going to enjoy listening to. And that is science writer Philip Ball, a former
editor at the prestigious journal Nature, who has written extensively on a variety of science
subjects, not only the biological sciences, chemistry, and science history,
but also quantum mechanics. So I present to you Philip Ball… What’s the difference between a living
thing and one that’s not alive? Scientists haven’t yet found an answer they all agree on,
but one thing we can say about living organisms is that they do things to suit
themselves. They rearrange their surroundings for their own purposes.
That’s not just a matter of me manipulating a cup, kettle and teabag to make a cup of tea.
Even single living cells act with agendas. Take the white blood cells called
macrophages in your immune system that engulf and eat invaders like bacteria.
Under a microscope you can watch a macrophage chase a bacterium across the slide, switching
course this way and that as its prey tries to escape, before finally catching the
rogue microbe and gobbling it up. This might sound like an anthropomorphic
way of describing a biological process. After all, single cells don’t have minds of
their own – so can they really have goals? Biologists often insist that cells and
bacteria aren’t really trying to do anything. In the end, they say, it all comes down to genes
and molecules, chemistry and physics – events unfolding with no aim or design, but
which fool our narrative-obsessed minds. Yet our sense that the macrophage does have
a goal and a purpose isn’t just a story that we ourselves create. After all, cells like
this exist precisely to conduct this kind of “seek and destroy” mission. What we’re talking
about here is agency: the ability of living things to alter their environment (and themselves)
with purpose, to fulfil an agenda. Agency is a genuine natural phenomenon –
and maybe biology would be less coy about it if we had a proper theory of how it arises. No such thing exists yet, but there’s
increasing optimism that it can be found. A theory of how agency arises could help us
interpret what we see in life from cells to societies, as well as in some of our
‘smart’ machines and technologies. It might even help us to understand
what “free will” can and should mean. Agency supplies what genetic hard-wiring
cannot. It’s just not feasible to programme complex living organisms for every
situation they might encounter: often they have to make choices in response to new and unforeseen circumstances. When
a hare is being pursued by a wolf, there’s no meaningful way to predict how both
animals will dart and switch this way and that, nor whether the hare’s gambits will let it elude
the wolf. Both are exercising their agency. In particular, the hare is trying to escape by
being unpredictable. An organism that reacts differently in seemingly identical situations
stands a better chance of outwitting predators. That can also be a good way to search for
food when you have no idea where it might be. You don’t even need a mind to be
unpredictable. Take the ciliate, a single-celled aquatic organism that attaches
itself like a sea anemone to surfaces. Disturb a ciliate with a jet of water,
mimicking the encroachment of a predator, and it may sometimes react by contracting,
and sometimes by detaching and floating away, with unpredictable, roughly 50:50
odds. Evidently, you don’t even so much as a nervous system to get random.
It’s in selecting from this range of behavioural choices that true agency consists. That selection
is goal-motivated: an organism does this and not that because it figures this would make it
more likely to attain its desired outcome. The choices we humans make might be carefully
deliberated: we contemplate the imagined future scenarios if we do this or that,
involving our internal mental models of how the world works and of our position within it.
This ability is what we experience as free will, although of course it is far from free of all
kinds of constraints: our memories, emotions, social conditioning, not to
mention the laws of physics. But if we’re going to ascribe agency to cells
and ciliates, we can’t make it depend on such elaborate cognitive resources. And so we need to
ask: what, fundamentally, is choice all about? In the mid-nineteenth century, the
Scottish physicist James Clerk Maxwell imagined a very simple scheme for how an agent
could achieve a different outcome from the one the world would otherwise spontaneously produce.
Scientists at that time had figured out that all spontaneous change in the universe is governed
by the second law of thermodynamics, which states that the change must lead to an increase in
entropy – loosely speaking, in the overall amount of disorder among its constituent particles.
It’s because of the second law that heat moves spontaneously from hot regions to colder ones.
In 1867, Maxwell suggested there might be a loophole in the law that prevented
this inevitable slide towards disorder. He imagined an ingenious microscopic being, later
called a demon, that operates a mechanism to sift “hot” from “cold” particles in a gas confined
within a box. The demon would let the molecules pass selectively through a trapdoor in a wall
dividing the box in two, so as to gather the hot (faster-moving) particles on one side, and
the cold (slower) particles on the other. The second law says this segregation of hot
and cold should never happen of its own accord. But the demon conquers that thermodynamic
decree by gathering microscopic information about the particles’ motion: information we
could never hope to perceive. In doing so, the demon exhibits agency. It has a goal, and uses
the information it gathers to achieve it. Now, the demon can’t really defeat the second law – or
at least, not forever. To use the information it gathers about particles’ motions, the demon has
to first record them in a memory of some kind. But any real memory will eventually fill up –
and a box of gas contains a lot of molecules. So the memory has to be wiped every so
often to make room for new information. That erasure, it turns out, produces entropy. So
all the entropy lost by separating hot from cold is recouped by clearing the demon’s memory.
Yet what the demon achieves is precisely the characteristic of living
organisms: it creates and sustains a kind of order and organization in the face
of the tendency of the second law to erode it. So what we need to fully understand
biological agency, say complex-systems theorist Stuart Kauffman and philosopher
Philip Clayton, is a theory of organisation. That doesn’t really exist yet.
But the link between organisation, information and agency is becoming more clear
as scientists explore the fertile intersection of information theory, thermodynamics, and life.
In 2012, Susanne Still of the University of Hawaii, working with Gavin Crooks of the Lawrence Berkeley
National Laboratory in California and others, showed that any entity with a
goal – like a cell, an animal, or even a tiny demon – needs to have a memory if
it is to work efficiently without wasting energy. The agent can use its memory to store a
representation of the environment – a kind of simplified model of how the world around it works
– which it can then draw upon to make predictions about the future. That allows it to anticipate and
prepare for what’s to come, and thereby make the best possible use of its energy resources.
Using energy efficiently is a prime goal in evolutionary biology: an organism that
wastes less energy must devote less time to acquiring it, by finding food say.
But Maxwell’s demon is aware of events at the molecular level that no living organism
can hope to access, and this is what permits it to take control of what looks to us
like a random mess of moving particle. How can your goal be best achieved – how can you
maximize your agency – when you’re not all-seeing? Most real systems, especially biological
ones, are forced to operate on partial knowledge, and so they need to make
inferences, guesses and assumptions. Still, Crooks and their colleagues found that
in this case energy efficiency depends on an ability to focus only on the information that is
most useful for predicting what the environment is going to be like moments later, and filtering
out the rest. In other words, it’s a question of identifying and storing meaningful information:
that which helps you attain your goal. The more “useless” information the agent stores
in its memory, the researchers showed, the less efficient its actions. In short,
efficient agents are discerning ones. There are still many things to be understood here.
In general, the environment is not static but changing, and in fact the agent affects
its own surroundings through its actions. That creates a much trickier scenario.
The agent might then be faced with the choice of adapting to circumstances or acting
to alter those circumstances: sometimes it might be better to go around an obstacle, and
sometimes to try to tunnel through it. What’s more, taking action is only effective
when the environment can accommodate the change. There’s little point in trying to do something
faster than the surroundings can respond; if you stir a cornstarch slurry too fast,
it just goes stiff as the grains jam against each other. And in real life, agents might
have to find good compromises between several, perhaps conflicting goals.
And how, anyway, does an agent find a good strategy for achieving its goals?
Well, this might be easier than it appears. Some scientists have shown that the
…agency required to solve apparently complex problems can emerge from strikingly simple
behavioural rules. You don’t necessarily need a big brain to do it, but just the right rules.
Other researchers have shown that sometimes Maxwell’s demon can work best by taking a
gamble on when to open and close the trapdoor, rather than responding to every individual
molecule that comes along. Living agents surely have to be gamblers sometimes, because
life isn’t fully knowable or predictable. Here, then, is a story we can tell about how
genuine biological agency could have arisen that doesn’t seek any recourse in mysticism.
Evolution gives organisms goals – they want food or water, say – but doesn’t specify how best
to attain them. Instead, it grants them agency to figure it out for themselves. They must be able to
generate alternative courses of action in response to essentially identical stimuli, to create
options and flexibility. They use their memory – an internal representations of the environment
– to predict the outcomes of these different choices, and to select what seems likely to be
the best. Organisms will have memories like this, if they have been selected to be energy-efficient.
At any rate, agency is neither a mere by-product of blind evolutionary forces, nor an
illusion produced by our tendency to project human attributes onto the world. Rather,
it’s a remarkable property that matter can possess – and one we should feel comfortable
invoking to explain how things happen. If we want to explain why a volcanic rock is at a
particular location, we can tell a causal story in terms of simple mechanics, devoid of any goal:
heat in the deep Earth, along with gravity, produced a convective flow of rock
that brought magma to the surface. However, if we want to explain why a bird’s
nest is in a particular location, it won’t do to recount the forces that acted
on the twigs to deliver them there. That explanation can’t be complete without
invoking the bird’s purpose in building the nest. We can’t explain the microscopic details – all
those cellulose molecules in the wood having a particular location and configuration – without
calling on higher-level principles of Agency. A causal story of the nest can never be bottom-up. Agents are
real causes of things that happen in the universe. I’d like to give a big shout out to
veteran writer Philip Ball for his fascinating narrative of this subject. He
has three new books coming out this year. But I think you might most enjoy reading
his book called, “How to grow a human” where he examines the new technologies that
allowed researchers to grow a kind of mini-brain from skin cells, and what they
might mean for our ability to repair, regrow and redesign the human body. It’s available
on Amazon and the link is in the description. Check it out! And if you have a question,
post it in the comments below, and I will try to answer it, I will
see you in the next video my friend!
