Editor's pick: I speak, therefore I am?
The explanation provided by Peter Halligan and David Oakley for consciousness 鈥� that it emerged as a side effect of communication 鈥� appears to depend on having language to convey useful information (15 August, p 26).
It seems clear to me that animals are conscious, with or without language. I also fail to see how language develops without consciousness.
I believe it is more likely that consciousness is an emergent, scalable phenomenon, developing when the brain has so many specialised subconscious systems that they survive better with central coordination. This central system would be adaptive when rudimentary and become more adaptive as it grew stronger 鈥� and that is the supervisory clearing house we call consciousness.
The subsystems would still retain their ability to make independent decisions; the purpose of consciousness may be to coordinate, influence or inhibit such systems by providing new inputs.
For example, my dog will search for me so that I can let him out to urinate, instead of just giving in to his subsystem insisting he do it immediately.
San Antonio, Texas, US
Not all women are equally fertile
Your “fertility calculator” article, which examines how a woman’s chance of having a particular number of children changes with age, gives a misleading view (1 August, p 6). It mentions in passing that the calculation “won’t apply to every woman on an individual basis as there is a lot of variation”, but then ignores that essential caveat.
Roughly half of women have high fertility, a further quarter have good fertility, while the remaining 25 per cent have trouble conceiving. The ages at which these women should start having children and the extent to which IVF can help them vary immensely. Averaging together people with such different experiences gives a result that cannot serve as a useful indicator.
A far better measure would be fertility testing for young women, which could tell them whether they are in the low-fertility category.
Ithaca, New York, US
<b>First class post</b>
That’s the easy part. The hard part is convincing these New Age parents to vaccinate their kids
Chad Myers says a universal influenza vaccine (29 August, p 7).
Opening up a can of earworms
Sam Wong’s article “Can’t get that song out of your head?” states that “Earworms are spontaneous thoughts” (25 July, p 10).
As one who has made a pastime of identifying earworm triggers, I’m able to report that they are often traceable to an external stimulus, and cases where I was unable to identify the source may just be a reflection of incomplete detective work.
It is interesting that the trigger need not be actual music. For example, on one occasion I realised that prior to hearing a symphony by Georges Bizet, I had seen the name “Bizet” on a magazine cover.
Identifying the trigger isn’t always so straightforward, because the mental sequence leading to the earworm may be longer or not as direct. Further, one earworm can easily morph into another, thereby confusing the trail.
I conclude that if there are spontaneous earworms, they are outnumbered by those initiated by an external stimulus.
Armidale, New South Wales, Australia
Opening up a can of earworms
Whatever a spontaneous thought is, it is hard to imagine a less spontaneous thought than an earworm 鈥� a bit of music that repeats itself endlessly after entering the brain by listening.
A far more useful concept would be seeing the obvious similarity between earworms and normal thoughts, which very frequently have an obsessive, repetitive quality.
Sydney, Australia
A universe quite by chance
I enjoyed your feature exploring discoveries that would change what it means to be human (8 August, p 28), and would like to suggest my own.
What if the fabric of the universe turns out to be random? It does seem that the more we delve into it, the more complex it becomes. To begin with, we explained the universe with Newton’s relatively simple laws of motion, which were superseded by general relativity and quantum mechanics.
Now it looks as though string theory may explain everything 鈥� but how many dimensions will we need? Will it be 10? Or 26? Or perhaps we will eventually need an infinite number.
Abinger Hammer, Surrey, UK
What are little asteroids made of?
Under the title “Space bling” you mention that asteroid 2011 UW-158 “is thought to have a core made of platinum” (25 July, p 5).
This seems unlikely to me. I have no reason to doubt that some asteroids are rich in precious metals, including platinum, but the term is relative. Here on Earth, in the platinum mines of South Africa, processing around 10 tonnes of rock yields less than 30 grams of pure platinum.
Looking on the bright side, mining these asteroids could give a kick-start to our moribund space programme. Scientific knowledge and national prestige have failed to get us out of Earth orbit for the last 43 years.
Slough, Berkshire, UK
What are little asteroids made of?
鈥� Planetary Resources asteroids they hope to mine as “composed of primarily metal. Some… large asteroids were pulverised in massive collisions early in the solar system’s history leaving only the tough metallic cores.”
Planet killers are a daily occurrence
It is interesting to read about possible asteroids in other solar systems (12 August, p 15). I wonder if those asteroids hit rocky planets as often as such bodies hit Earth, say every 100 million years for an impact the size of Chicxulub, thought to have wiped out the dinosaurs. With some 30 billion rocky planets in our galaxy, that would mean one giant impact every day. A sobering thought for the chances of advanced life.
Beacon Hill, New South Wales, Australia
A nose for thyroid problems
I’d like to contribute a small anecdote to the correspondence on sniffing out illnesses (Letters, 18 July).
In the early 1960s, one of my jobs at Leeds Infirmary, UK, was administering tiny doses of radioactive iodine to people with a possible malfunction of their thyroid glands. Hyperthyroidism is often quite easily spotted because it causes bulging eyes and general hyperactivity, but I gradually became aware that I could detect a faint whiff from those with the condition, which I described as a cross between the ketotic smell of diabetes and the aroma of burnt carrots.
The consultant endocrinologist for whom I worked could not detect any odour. We carried out a short trial that was as rigorous as we could make it given the circumstances and the relatively small numbers involved.
I forget the actual numbers 鈥� it was over 50 years ago 鈥� but my success rate in identifying thyrotoxics was significantly better than random. The trial was not published, although I believe a short letter appeared in an appropriate journal.
Kirkby Malzeard, North Yorkshire, UK
Should we hive off civil time?
Richard Keyworth asks whether we could redefine the second and so reduce the discrepancy between atomic time and civil time (Letters, 15 August).
We could, but we would need to do so repeatedly. The atomic second corresponds to what was appropriate in the late 19th century 鈥� namely 86,400 seconds per day 鈥� and now it’s a bit too short because the day has got longer. If we were to redefine it, we would face the same problem again in 100 years because Earth’s rotation will continue to slow.
One solution might be to keep a scientific and technological second as defined now, and a civil second that would be a little longer and would be lengthened every 50 years. This would eliminate the need for leap seconds.
Les Essarts-le-Roi, France
It's realistic to be alarmed
There are many areas of uncertainty associated with climate change, but for scientists to continually err on the side of being conservative does not serve their wider audience at all. In fact, it inhibits urgent action.
It is clear from your piece on superstorms (1 August, p 9) that one scientist, James Hansen, has not lost his sense of realism and has consistently made predictions that prove to be far more accurate than those of his colleagues.
Nearly all other “official” projections of climate scientists have turned out to be too conservative. If the talks in Paris at the end of the year are to make progress toward correcting the present situation, then real scientists being realistic must be heard loud and clear.
Port Lincoln, South Australia
It's realistic to be alarmed
Typhoons are being made worse by global warming, but I believe we can try to reduce their power and/or frequency.
Hurricanes, typhoons and cyclones get their energy from a relatively thin layer of warm water at the surface of tropical seas. This layer also threatens phytoplankton with overheating.
Satellite heat sensors show these storms leave a line of cooler water in their wake 鈥� which we have the technology to emulate by bringing cold water from deeper down during the typhoon season to deny these storms the energy they need to worsen. One method would be to bubble compressed air into the sea at a depth of, say, 100 metres.
Plymouth, UK
Scouting for true north
I was surprised that someone would go to the trouble of using GPS and a digital camera to find true north from the position of the sun (8 August, p 13). Anyone who was ever a boy scout knows with an old-fashioned wristwatch.
Jomtien, Thailand