26 | New Scientist | 7 September 2019
Editor’s pick
Some people without
language can think
Letters, 20 July
From Peter White, Cardiff, UK
David Werdegar says “it is
impossible for us to think without
language”. But people who have
severe aphasia – loss of language
abilities – because of strokes or
other brain damage may be
unimpaired in other thinking
abilities, including arithmetic,
logical and causal reasoning,
chess playing, spatial navigation
and theory of mind (thinking about
the mental states of other people).
This doesn’t mean that language
isn’t one of the wonders of the
human brain. We shouldn’t, though,
overestimate the extent to which
other cognitive capacities depend
on it. It isn’t clear what this tells us
about the thinking abilities of other
species, because their brains differ
from ours in many ways, but their
lack of language doesn’t justify
the claim that they can’t think.Little Sun’s ‘social change’
doesn’t change enough
13 July, p 28
From Christine Wolak,
Dublin, California, US
The news from Olafur Eliasson
that Little Sun lamps increase the
homework efficiency of girls in
households without electricity
by 80 per cent isn’t inspiring:
it’s a sad story about the unequal
expectations for boys and girls.
I support the health and
safety and climate justifications
for replacing oil lanterns with
solar-powered LED lamps. But
describing how they enable girls to
do the dishes and their homework
while boys only do the latter tells
girls that they can study and still
have time to take care of everyone
else. Where does that extra time
come from? Most likely from
either sleep or play – time that a
boy gets but a girl doesn’t. Unless
this extra homework time leads to
increased opportunities for girls,
will it really matter in the end?We and our microbiome
can have diet advice13 July, p 32
From Dusan Cech, Farnborough,
Queensland, Australia
Clare Wilson does a good job
revealing the pitfalls of most
studies looking at diets. She
could also have mentioned the
emerging discoveries of the health
effects of the composition of our
microbiome – the organisms
in our gut and on our skin, for
example. Perhaps knowledge of
how changes to diet can affect this
composition will become the next
form of dietary advice when it
goes mainstream.From William Meggs,
Greenville, North Carolina, US
Wilson correctly points out the
limitations and inconsistencies
of observational studies based on
questionnaires, and the inability
to perform randomised controlled
studies of diet and health. She
concludes that the problem is
serious enough that we should
be sceptical of all dietary advice.
But there are studies that
examine health differences in
geographical populations withdifferent diets: for instance, those
comparing northern European
populations that typically
consume more animal-based
fats with southern European
populations whose diets feature
fish, vegetables and olive oil.
Other studies compared the
health of Japanese immigrants
to the US who adopted typically
lower-quality American diets
with those in Japan who followed
a traditional diet.
Studies comparing vegetarians
with meat eaters support the value
of a vegetarian diet.Experiencing a feeling of
frustration about qualia
22 June, p 34
From Ben Haller,
Ithaca, New York, US
Trying to explain away the
“hard problem” of consciousness,
Rowan Hooper claims qualia are
illusory and so there is nothing
to explain. He says “we don’t
normally talk about our qualia,
we talk about things such as being
tired”. But that misses the point.
A smartphone can register
that its battery is low, display a
low-battery icon on its screen andshut off safely when its power
level gets too low. But nobody
would claim that the smartphone
“feels tired”. It isn’t experiencing
tiredness in a conscious way like a
human. It experiences no qualia.
That is the problem to be
explained, and no amount of
hand-waving about “illusions”
will make it go away. Even if qualia
are illusory, the hard question
remains: how is it that such
illusions produce a conscious
experience in a human brain?Is it worth studying the
health of toothless people?
10 August, p 42
From William Graham,
Grange-over-Sands, Cumbria, UK
Debora MacKenzie reports that
infection with Porphyromonas
gingivalis, a bacterium involved
in gum disease, may cause a
variety of serious diseases. I have
heard that having all one’s teeth
extracted was a not uncommon
21st birthday present in parts
of England until the middle of
the 20th century. It would be
interesting to know if any similar
studies have been carried out on
the health of people without teeth.Views You r le t te r s