26 | New Scientist | 7 March 2020
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Editor’s pick
Can we model decision-
making in single cells?
15 February, p 34
From Paul G. Ellis,
Chichester, West Sussex, UK
Speaking to Richard Webb, Sean
Carroll wonders whether bacteria
have decision-making power or
agency. Arguably, the earliest
known “decision-making” in the
burgeoning tree of life occurs with
chemotaxis: single-celled life forms
propelling themselves in response
to a chemical stimulus, for example
towards sources of nutrients.
Webb later quotes researcher
Larissa Albantakis, who argues that
the apparently deliberative quality
of our agency sets it apart from this:
it “is not just reflexes”. But bacterial
chemotaxis is more than a single
reflex action. It is a response to
an environment that results in the
selection, over alternatives, of one
near-optimum direction to move in.
Information scientist Susanne
Still says that agents follow rules
that must fulfil certain criteria,
including some element of memory
storage and recall. Evolutionary
processes constitute a memory
function and provide this feedback,
but over generations rather than
within an individual cell.
So could focusing on a primitive
form of agency – the ability to select
one optimal direction from many –
in a system as simple as a single cell
help determine whether agency
can, in principle, be explained in
purely physico-chemical terms?How can evolution happen
without external reality?
1 February, p 39
From Paul Mealing,
Melbourne, Australia
Your collection of articles on
reality was informative. Most
provocative was Alison George
reporting Donald Hoffman’s
claim that nothing we perceive
resembles reality and we are “born
with a virtual reality headset on”.
He says evolution gave us this to
simplify things so we had “whatwe need to play the game of life”,
and that what we perceive is an
abstract data structure that
represents something that
“doesn’t even exist in space
and time”. The implication that
evolution therefore doesn’t occur
in space and time creates problems
for me. Hoffman goes on to say
that evolution has shaped us to
see things that we have to take
seriously, to see what we need
to stay alive, but that “does not,
logically, permit us to say that
we’re seeing the truth”.
But evolution occurs by natural
selection, which requires an
environment for biological agents
to interact with. Assuming that we
are born with such a VR headset,
the “data structure” it creates
must surely closely resemble the
external environment it interacts
with in space and time – otherwise
we wouldn’t survive.The importance of naming
our parts correctly
11 January, p 30
From Alan Moskwa,
Adelaide, South Australia
Clare Wilson says that educating
people about sexual health ismore important than policing
their language to prevent
them referring to the vulva
as the vagina. Yet that is akin
to calling the lips the throat.
Such errors can lead to serious
misunderstandings. One of my
patients was convinced he had
rectal cancer. In reality, he had a
skin cancer just outside his anus. I
couldn’t convince him otherwise.Fictitious women are
more equal on Wikipedia
8 February, p 46
From Krista Nelson,
Rokeby, Tasmania, Australia
I am amazed that some Wikipedia
editors deem female scientists
to be “not notable enough for
inclusion”. Many characters from
anime films have their own pages,
even supporting characters.The meaning of life is
simpler than it seems
Letters, 11 January
From Colin Walls,
Sidmouth, Devon, UK
People are intrigued by the
Canadian frogs that freeze in
winter and thaw out in summer.Are they alive or not? It sounds
like a deep philosophical question,
but it isn’t.
“Life” is a collective noun
for things that are living. Things
transition from being dead to
alive all the time. Every time you
breathe in, atoms that were dead
are incorporated in your body and
begin to live. When you breathe
out, atoms that were living are
sent into the atmosphere and are
now dead. Life isn’t a substance:
it is an activity.
So are the frozen frogs active?
No. Therefore they aren’t living.
When you thaw them out, are
they active? Yes, so they are living.
As every detective story teaches
you, it is the time of death that is
important. Whether something is
alive or not can only be answered
with reference to a time. This is
the meaning of “life”.Don’t forget the role of
the body’s thermostat
18 January, p 13
From Richard Burton, Glasgow, UK
Average human body temperature
has fallen in the US since the
1860s, reports Michael Marshall.
Julie Parsonnet, one of the team