38 | New Scientist | 15 February 2020“Agency is not just reflexes,” says Larissa
Albantakis at the Center for Sleep and
Consciousness at the University of Wisconsin-
Madison. “If you’re only reacting to the
environment, you’re not an agent, you’re
just a system going through the motions.”
The apparently deliberative quality of our
agency sets it apart from, say, bacteria
responding to chemical stimuli, or even
frogs reflexively snapping at passing flies.
“We collect influences from our past, we
subject those influences to reflective process,
we somehow extract things like hope and
dreams and bring them to bear on behaviour,
to mediate between the influences impinging
on us,” says Ismael.
Together with her colleague Giulio Tononi,
Albantakis has recently shown how systems
with the same overall physical dynamics, but
different internal ways of dealing with and
distributing information, can develop different
degrees of autonomous agency. Meanwhile,
Still has found that information-acquiring
machines built to retain memories and
operate at maximum thermodynamic
efficiency necessarily only retain new
information with predictive power. “What
emerges is an information bottleneck – a
method that tells you to distil relevant,
predictive bits and to throw away irrelevantWhen it comes to the relationship
between our power of agency and
physical laws (see main story),
quantum theory at first seems to
send us spiralling into a new total
perspective vortex.
The difficulties are best illustrated by
Schrödinger’s cat, the notorious feline
that exists both killed and not killed
by the random quantum decay of a
radioactive atom, until – in the standard
telling at least – an observer determines
which by looking in their kitty carrier.
Erwin Schrödinger was motivated
to this absurdist thought experiment by
a seemingly absurd reality. In quantum
theory, objects are found not in definite
states, but as probabilistic “wave
functions” that allow the simultaneous
existence of several different possible
states. Make a measurement, however,
and a single reality emerges. Quantum
experiments back this up. Repeatedly
measure the same quantum object and
you won’t measure the same state each
time. Instead, a pattern of results will
slowly develop corresponding to the
probabilities of the different states
encoded in the wave function.
At face value, the process of “wave
function collapse” to create a single
defined reality brings an unwelcome
new twist on agency: we as observers
get to bring reality into being, but
with no power over what we get.
“Quantum mechanics doesn’t insert us
into the causal chain,” says philosopher
Jenann Ismael of Columbia University
in New York. “It inserts uncontrollable
events into the causal chain.”
Things get even weirder with
recent, more complex versions of
Schrödinger’s thought experimentin which two different agents
simultaneously see contradictory
versions of the same reality. So does
agency break quantum theory?
Probably not. More plausibly, this
is evidence that we need to work on
our interpretations of quantum theory,
and that versions that credit observers
with creating reality don’t cut it. Many
physicists don’t need convincing. “It’s
plainly bananas to believe you’ll have
no measurement results until the first
human life evolved,” says Matt Leifer
at Chapman University in California.
Others see in it vindication for their
own interpretations. Sean Carroll at
the California Institute of Technology,
for example, is one of many adherents
of the many-worlds interpretation
of quantum mechanics. This says
that when we make a quantum
measurement, we don’t decide
anything, but are merely conveyed with
the result of our measurement into one
of many parallel realities corresponding
to all the possibilities encoded in the
wave function. “Despite the name,
many worlds has the simplest, smallest,
most compact fundamental picture of
reality,” says Carroll. “It’s just a wave
function obeying an equation.”
The consequences might seem
dramatic, with an infinity of parallel
universes popping into existence at
every fork in the road, but at least it
would mean there is no particular
quantum mystery to agency. “Attaching
any special notion of agency to the
collapse of the wave function makes
no sense,” says Carroll. “But things like
how do I choose what clothes to wear?
That’s a perfectly reasonable question
where agency is obviously involved.”NO ‘I’ IN COLLAPSE
The role of
observers
in quantum
mechanics
is highly
mysteriousVICTOR DE SCHWANBERG/SCIENCE PHOTO LIBRARY
MACIEJ BLEDOWSKI/ALAMY STOCK PHOTO