Quantum quirks
I greatly enjoyed Matthew Chalmers’s article on the subjective nature of reality and how “quantum weirdness is all in the mind” (10 May, p 32). The same problem of subjectivity arises in psychology when theorists tie themselves in knots trying to relate abstractions such as intelligence or personality to everyday experience.
Quantum theory cannot “make sense” without a human to make sense of it. What a scientist’s apparatus registers while they are unable to record it is unknowable and therefore scientifically meaningless. Quantum theory comes up with “the right answer” because people have struggled hard to make it that way.
As David Mermin says in the article, “it really is that simple”, just as long as we remember that theories are human constructions and imperfect for that.
Darlington, Western Australia
Quantum quirks
If quantum weirdness is all in the mind, what about optical interference?
Set up apparatus that can record the arrival of an individual photon on a screen after passing through one of two slits, and then ask: “Which slit did that particular photon pass through?”
It will never arrive at a point not allowed by the two-slit interference of waves.
Light travels as waves and arrives as particles. This is a weird duality that is inescapable.
Malvern, Worcestershire, UK
Quantum quirks
Quantum Bayesianism, which views quantum states as existing only in our minds, seems a red herring that leads you into a strange maze of inter-subjectivity.
What happens when the scientists communicate with each other and collate their individual observations? They cannot help but arrive at objective laws of physics, such as entanglement, and so we end up coming full circle back to objectivity.
Cardiff, UK
Quantum quirks
Chalmers highlights the way a metaphor may be mistaken for reality. This reminded me of George Lakoff and Mark Johnson’s book Metaphors We Live By, which reveals how fundamentally these structure our thinking.
They demonstrate the deeply embedded nature of metaphor within language, and the way this routinely escapes our notice. For me, their ideas also made it easy to view a quantum Bayesianist argument as plausible.
Eccles, Kent, UK
Attitude adjustment
Clare Wilson’s article on how doctors diagnose mental health problems took a tone that was rather sensationalist and negative (10 May, p 10).
It strikes me that those working at the front line of anthropogenic climate change are generally portrayed in your magazine as heroes. Their scientific evidence requires further refinement, but it is considered by most that we should act prudently to prevent climate deterioration.
Psychiatrists treat people more effectively now than 20 or 50 years ago, using the Diagnostic and Statistical Manual of Mental Disorders (DSM) as a rough guide. We understand that it is flawed, and don’t use it as a bible.
There are other areas of medicine in which doctors have fairly generic approaches to treating conditions that require further research to clarify the cause. Prostate cancer, rheumatism and even skin conditions remain somewhat mysterious but do not face the same kind of criticism. Those specialists are not in need of a “reboot”, so why is psychiatry?
Burwood, Victoria, Australia
Attitude adjustment
The view that psychiatry needs a reboot comes not from our own quarters, but from the practitioners themselves. Last year, Thomas Insel, director of the US National Institute of Mental Health, announced on his blog “will be re-orienting its research away from DSM categories”.
Mind altering
In Anil Ananthaswamy’s piece on why robots will never be conscious, Phil Maguire says that his team’s proof would not hold up if information integration in the brain was reversible (17 May, p 12).
He will be disappointed to learn that memories can indeed be broken down and edited.
Memories are also not lossless; the act of recalling them changes them. Some things get added during the process of recall, some reinforced, and others subtracted.
In light of this, we can say that memory is not unchanging, like a photograph, but something rather fluid and in flux. Perhaps the brain really is continually haemorrhaging information.Ambergate, Derbyshire, UK
Mars attacks
I am appalled by the proposal from Explore Mars to use a battery of ground-penetrating missiles in the search for life on the Red Planet (10 May, p 14).
Clearly executive director Chris Carberry slept through Ethics 101. If there is life of any sort on Mars, by what right do we rain down bombs on their heads?
Buderim, Queensland, Australia
Infinite failure
In discussing the infinitely multiplying multiverse, Lisa Grossman states that given enough time, anything that has a chance of happening will happen (17 May, p 8). This is not the case.
If you start counting in the usual way: “1, 2, 3…” and carry on until infinity, you will never get to -3, 42.5 or Pi.
It is quite possible for the number of things spawned by the multiverse to be infinite, but to exclude infinitely many configurations. Much to my disappointment, therefore, an infinite multiverse is not guaranteed to contain a perfect replica of Tolkien’s Middle-earth. Or indeed, Boltzmann brains.
London, UK
A stitch in time
Aviva Rutkin’s article about a 3D printer that uses yarn sounds very much like knitting, and in particular a Jacquard machine (17 May, p 21).
This specialised loom uses a device to carry the yarn over a series of programmable knitting needles, allowing various 3D articles to be made.
One could use yarns with different properties to make products more flexible at different points, and it may be possible to incorporate electrically conductive yarns.
The company where I worked 40 years ago produced a safety glove with electronic components, but there was not a lot of interest because of the difficult economic conditions at the time.
No doubt modern sensors and electronics could produce a similar piece of clothing which would save lives and money.
Lathom, Lancashire, UK
For the record
鈥� Our logic got fuzzy when considering the likelihood of conscious robots (17 May, p 12). The outputs should be swapped in our description of an XOR logic gate.