2019-04-20_New_Scientist

54 | NewScientist | 20 April 2019

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LETTERS

arrive at a new equilibrium

that removes the cause of

the problem: us.

From David Ashton,

Sheringham, Norfolk, UK

Isn’t the most remarkable fact

about the evolutionary process

that, by means of the human

brain on this planet, the

“universe” is asking questions

about its own existence?

Yet another odd reason

for removing teeth

From Crispin Piney,

Mougins, France

Terrance Chapman doesn’t know

the reason for his mother-in-law’s

total tooth removal in the 1930s

(Letters, 16 March) and Aroha

Mahoney says a neighbour’s were

removed in the 1950s to save her

husband money (Letters, 6 April).

My father, who suffered the same

fate in the early 1900s, explained

that this treatment was based on

the idea of “focal infection” made

popular around that time by the

surgeons William Hunter and

Frank Billings. Various supposedly

superfluous parts of the human

body such as teeth, tonsils,

spleen and testicles were removed

as a precaution against a range

of ailments including anaemia,

arthritis, schizophrenia and

bipolar disorder. Having

sacrificed only his teeth, he felt

that he probably got off lightly.

Could Neanderthals have

farmed these rabbits?

From Ralph Reid, Coolamon,

New South Wales, Australia

You suggest that the absence

of infant rabbit bones at

Neanderthal sites means that

rabbits were hunted individually

rather than flushed from burrows

(16 March, p 20). It is also possible

that rabbits were raised in

captivity and harvested only

as adults. I am sure that the

Neanderthals were smart enough

to cotton on to that concept.

Greens with a side of

poisonous arsenic

From Aidan Karley,

Brechin, Angus, UK

So a species of caterpillar happily

dines on arsenic-loaded leaves

(16 March, p 20). I recall how a

suggestion that microbes could

substitute arsenic for phosphorus

in their biochemistry (26 April

2008, p 10) caused a mild furore

and then rebuttals (28 January

2012, p 6).

Wouldn’t such caterpillars

be the place to look for the

biochemical co-option of arsenic,

and even its active elimination,

rather than microbes that are

unavoidably – at the per-microbe

level – washed in the element?

That these caterpillars

bioaccumulate may be an

indicator that eukaryotes don’t

have the biochemical flexibility

to do more than isolate the stuff,

and can’t even excrete it.

Size matters for our

friends’ quantum views

From Nick Canning, Coleraine,

County Londonderry, UK

You draw the conclusion that

alternative facts are real from

a paradox, which arises from a

thought experiment about the

states of friends of observers of a

quantum event (2 March, p 7). This

would only be true if we accepted

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that an unambiguously quantum

object such as a single photon can

be “an observer” equal in status to,

say, a cat, and you quote physicist

Renato Renner challenging this.

The formalism employed in

analysis of the experiment treats

observers, be they photon or cat,

in exactly the same way. But this

ignores the problem of how the

size of an observer contributes

to the decoherence of entangled

superposition states. This means

that a cat can never be observed

in a superposition state from the

point of view of a friend sitting

next to it. The existence of these

superposition states is essential

to the conclusion that different

observers will disagree about a

particular fact.

We probably can’t smell

the presence of one gene

From Richard Harris,

Ottawa, Canada

Geoff Convery suggests that cystic

fibrosis carriers might recognise

each other through olfaction

(Letters, 2 March). But cystic

fibrosis is caused by a mutation in

a single gene. It seems extremely

unlikely that one mutated gene

among tens of thousands would

be detectable by smell.

For the record

Q However it may be discovered

that functional disorders arise, there

is no suggestion that it is through

conscious thinking (6 April, p 28).

Q The philosopher Daniel Dennett

popularised the word “sphexish”

to describe rigidly-determined

behaviours, but did not coin it

(6 April, p 34).