What is 'reality'?
My appreciation for Roger Penrose’s essay asking “What is reality?” was diminished because he gave no clear-cut definition of what he means by “reality” (18 November, p 32).
As a result, the discussion seemed like nothing so much as an overview of the implicit etymology and current range of English-language meanings of that word. One can easily imagine dictionary definitions that either include or exclude physical events at the quantum scale, or human mental events such as unexpressed thoughts.
I am not a linguist, but I suspect that the words for “reality” in other languages may not exactly coincide with the English meaning that Penrose assumes, whatever that may be. Even within the confines of the English language, philosophers devote their life’s work to developing and defending definitions of reality and other indeterminate concepts. Perhaps Penrose could offer a dictionary definition of “reality” as a starting point for understanding his arguments.
Simulation falls over
I am unable to distinguish between Nick Bostrom’s “We are living in a computer simulation” (18 November, p 38) and Archbishop James Ussher’s 1650 proclamation that the world was created by God on 23 October 4004 BC. According to later interpretations this creation included the cosmic background radiation, dinosaur fossils and carbon-14 ratios set up appropriately to mimic a very much longer history.
The only extra information from Bostrom’s scenario is that we now know how God was created 鈥� he is a simulation by a previous God.
Perhaps Bostrom’s first proposition is correct and no civilisation has achieved technological maturity. Indeed, this has already been proved to be the case.
The mathematician John von Neumann showed that any technologically mature civilisation would be capable of making self-replicating probes and that they would surely use such devices to explore the galaxy. Since each probe would produce multiple copies of itself at each planet-fall, the galaxy would be awash with such probes and we would certainly have seen them. The fact that we have not is therefore proof that no technologically mature civilisations exist.
Unless, of course, the simulators deliberately omitted the probes from their simulation.
For the record
鈥� We gave the impression that Teodor Silviu Balaban and his team are attempting to mimic the light-harvesting mechanisms of plants or deep-water algae (11 November, p 30). Balaban is actually attempting to create artificial versions of the simpler chlorosomes found in early photosynthetic bacteria. We also erred in his affiliation: Balaban is at the Institute of Nanotechnology at the Karlsruhe Institute of Technology.
Teleport trouble
The philosopher Derek Parfit asks us to consider our body being scanned destructively and reconstituted at a remote location (18 November, p 56). Paul Broks cites this to point up a distinction between the “ego theory” by which destructive transmission of a human being somehow loses something identifiable in this process on the one hand, and the “bundle theory” in which that something is not recognised as lost because, however strongly it may be institutionalised or intuited, it is deemed not to exist.
This thought experiment, however, misses a point beautifully made by James Patrick Kelly in his short story Thinking Like a Dinosaur in which, because the scanning is not itself destructive, the “original” must be killed so that there remains only one person to identify as “the traveller”. In this, whether the traveller is viewed as “ego” or “bundle”, the same difficulties have to be faced: who is travelling, and who is destroyed? And why? Even the “bundle theory” would be hard pressed to justify destruction of the traveller at the transmitting end, whether inherent in the process of transmission or not.
Simulation falls over
When Nick Bostrom discusses whether we live in a computer simulation, he seems to assume no limits on the power of whatever runs the simulation (18 November, p 38). Futurologists have seen computing power advance geometrically in recent years and expect this trend to continue into the future.
They may be falling into a trap. Many common fallacies are based on belief in indefinite geometric increases. It is true that computer processor speeds have increased geometrically over several decades, but this rate of increase has already stalled. The sizes of processors and memory continue to increase geometrically but will not continue to do so once fundamental physical limits are reached.
Even if we reach these limits, a computing device will always be much more massive than the object it simulates, because an accurate simulation of reality would contain every quantum state of every fundamental particle in the simulated object. Scientific observation in fields from nuclear physics to astronomy show no evidence for suspicious “low-resolution approximations” in any corner of our universe. We cannot, so far, even simulate objects comprised of a few molecules. Even assuming that an advanced civilisation could simulate an entire world, they would need computing resources very much larger than a world.
Thus only a tiny part of the universe could be simulated using the resources of the remaining universe. This seems incompatible with Nick Bostrom’s suggestion that there could be billions more simulations of civilisations than there are civilisations.
Life, but not as we know it
I find the definition of life as a “self-sustained chemical system capable of undergoing Darwinian evolution,” a surprising one to have gained credence (18 November, p 46). Darwinian evolution can refer only to a group of entities, and indeed many generations thereof. As such, if I were the last human in existence, I would not be considered as “life” by this definition as I would no longer be capable of Darwinian evolution. GM crops which produce sterile seeds would be further examples of non-life.
The mistake that has been made is to constrain all possible forms of life by the definition of the only example we know of. I can envisage a planet where a freak occurrence in its sea of chemicals gives rise to a complex cellular system. The system grows by a mechanism akin to cell division, but every cell is the same as the last. Change is not necessary, for it resides in a nutrient-rich, stable environment with no competition. Existence is a cinch. After millions of years it covers more than half of the planet’s surface.
Maybe one day it will cease to exist because it will have consumed all available resources. Is this system undergoing Darwinian evolution?
No. Is it alive? Of course.
It’s not hard to envisage such life, and many other wackier examples.
So, it’s not hard to realise that Darwinian evolution has no place in a definition of life.
杏吧原创s against God
I was shocked to read the attitude to the 15 per cent of US National Academy of Science members who are not atheist at the La Jolla meeting entitled “Beyond belief” (18 November, p 8). For me science and religion complement each other. Religion gives me a purpose in life, and science makes me understand how the universe works. Religion will never explain to me how the universe works except metaphorically, and science will never give me a driving force behind what I do and how I live.
I blame American education boards for the misunderstanding. Here in London I was taught both religion and science, in a passive way. We studied different religions and tried to understand why they believed certain things, and to respect the differences. In science we learned of major discoveries, with some teachers reminding us that every theory and discovery is right until proved wrong. If US education tried this approach, I am sure that we would hear less about home-schooled kids being taught science with an extreme religious viewpoint, or scientist trying to replace religion and ban it.
From Andy Lawrence
In your 50th anniversary edition, it was fascinating to see an article on the antagonism between scientists and religion (page 8) in the same issue as an article by Paul Broks describing the “bundle theory” of self (page 56), as the latter seemed to be an almost perfect description of the Buddhist teaching that the self is an illusion caused by memory and fear of death. Of course many would declare Buddhism not to be a religion, even seeing it as a route to a special kind of atheism. Without getting into semantic tangles, perhaps it is fair to say that a desire to think about spiritual issues is not of itself inconsistent with a rational and empirical approach to life. It’s just that in practice most religions are primitive fairytales, and what’s worse, fairytales embedded in repressive social structures. Even Buddhism in practice seems to descend into ritual and magical thinking, and the philosophy of the Vedanta seems to shore up the Brahmin class tyranny. Of course science could never be used to justify a repressive social structure… could it ?
Edinburgh, UK
Fat is a fear issue
While the authorities in the western world prepare to allocate fortunes in public funds to address a growing obesity problem in their populations, your article “Supersize surprise” eloquently shows how little we understand of the phenomenon (4 November, p 34). I would like to suggest an avenue of research that may not yet have been explored to explain such widespread obesity. You could call this the “impending doom factor”.
Could the human animal be reacting to daily poundings of threats to its very survival? Be it cataclysmic climate change or Armageddon, such threats of impending doom can surely trigger behaviours meant to ensure survival. Just as other animals make provision for winter (often in the form of body fat), couldn’t we be unconsciously taking measures to withstand the threatened hardships?
There have been wars and famines throughout human history, but never before has there been such an abundance of available food. If there seems to be no hope of avoiding doom 鈥� if, for example, our leaders refuse to act on climate change or seem dead set on engaging in a new world conflict that promises to be a major slaughter 鈥� what can the individual human do but prepare for the worst?
Even if some of these dangers are imagined rather than real, trying to curb behaviours that increase body fat may be useless, as they are mere symptoms of a will to survive in the face of a perceived peril.
Small steps on climate
I find it hard to accept your criticism of what the European Union accomplished at the Nairobi climate conference (25 November, p 5). The EU set several goals which, perhaps surprisingly, were all reached. It is important to take even small steps forward when some in the crowd are still walking backwards.
Of course it would have been great to agree upon a timetable and new limits for greenhouse gas emissions. However, when the governments are not ready, they will not act. It is for the politicians and the media to push them to take the necessary actions.
I have learned to understand that the media likes high-profile declarations. These often undermine what can be accomplished with low-profile diplomacy. I sincerely think there is already too much hot air in the climate talks.
Tiger farming
You report that China is promoting tiger farming as a way of protecting tigers in the wild by providing a legitimate source of sought-after tiger body parts (18 November, p 16).
Yet studies in India have clearly shown that the core cause for the decline of the tiger population is not the demand for parts, but activities such as habitat degradation and over-hunting of the tiger’s prey species. Several areas where tiger poaching is non-existent are bereft of the amber-eyed cat because its preferred prey have become rare or have even vanished. Conservation of wild species and landscapes should be looked at in the same way as public health or primary education 鈥� as bringing long-term intangible benefits to society 鈥� and not as “commerce” as you report Barun Mitra to be suggesting. Proposed solutions must be not only pragmatic but also socially and culturally acceptable, and they need to be based on understanding of their long-term impacts.
From Barun Mitra, Liberty Institute
I was recently present at a round table on tiger conservation, organised by the Competitive Enterprise Institute in Washington DC, and attended almost a who’s who of international tiger conservation groups based in the US capital. Even environmentalists now agree that tigers occupy 40 per cent less habitat area than they did 10 years ago. Habitat loss, not poaching, is contributing most to tigers’ decline in the wild.
While it may seem counter-intuitive, it is only when tigers become largely available and tradable products that the species will be spared extinction. In pragmatic terms, the animal is extremely valuable. Given the growing popularity of traditional Chinese medicines, the tiger can in effect pay for its own survival.
New Delhi, India
鈥� Our apologies to Barun Mitra for misspelling his name in the original article 鈥� Ed
Farmer-led forests
I was delighted to see you report the success of farmer-led efforts in Niger to reclaim the desert by growing more trees (14 October, p 11). If farmers in Africa’s poorest nation, working in an extremely harsh and unforgiving climate, can win the fight against desertification, it should be possible elsewhere in Africa and across the globe. The farmers succeeded where millions of dollars invested in conventional tree planting failed.
Through “farmer-managed natural regeneration”, as it has been called, they found that trees could regenerate profusely from re-sprouting stumps of native trees. Until recently, farmers slashed and burned these sprouts while preparing fields for crops.
Now they select and prune shoots sprouting from the stumps instead. Moreover, the resource is free. This is a major reason for the practice spreading rapidly in Niger.
For no extra cost, farmers could supplement their income by selling material from the trees, as well as doubling yields of crops grown in association with the trees, as reported in the article. This is a message that should be heeded throughout Africa, especially the parts slowly turning to desert. Governments, NGOs and international research organisations should re-examine their agroforestry practices in the light of this remarkable success.
How green is your roof?
A green roof with plants growing in a soil or mineral substrate does offer a number of benefits, as Helen Bantock says (18 November, p 25). But it also has a fundamental problem: it typically weighs up to four times as much as a conventional roof, and so needs larger supporting structures. These in turn require more concrete, steel and/or aluminium, all of which consume enormous amounts of energy during their manufacture.
The most common green roof construction is based on an aluminium “standing seam” roof sheet, which is one of the least environmentally friendly products used in the construction industry.
Laying soil and planting on top of this is very much the embodiment of a “greenwash” in which architects and owners proclaim false green credentials by pointing to their roof. Next time you see one of these, ask the structural engineer how much extra concrete went into the foundations and how much extra steel went into the structure to support it.
Causes of schizophrenia
You report that parental absence is linked to a significantly higher incidence of psychosis, and that Afro-Caribbean people are significantly more likely to have schizophrenia than white Britons (25 November, p 7). These findings, you suggest, “reopen the debate about the relative roles of genes and environment in schizophrenia”. I was not aware that this debate had ever closed.
Both genetic and environmental factors have been suggested to explain the apparently high incidence of schizophrenia among Afro-Caribbean people in England. Genetic predisposition, low maternal vitamin D levels during pregnancy, cultural differences resulting in over-diagnosis, excessive use of cannabis and, now, a high incidence of parental absence during childhood are all among the candidate explanations. Take your pick.
One of the researchers who reported these findings says that they “point quite strongly to environmental factors”. Perhaps. Might not the apparent link with parental absence equally well indicate that parents with psychoses, having passed a genetic predisposition on to their children, are less likely to maintain long-term settled family relationships than those without?
A kinder cut
While you report the medical benefits of male circumcision (25 November, p 8), I was a little taken aback by the discussion of its downsides in the boxed article “To snip or not to snip”.
You are right in saying that there has been relatively little research into the effects of circumcision on sexual pleasure, though you omit to mention that there has been one recent and substantial contribution on this topic. This was the Australian survey of over 10,000 men by Juliet Richters and colleagues, which showed that circumcised men were much less likely to experience pain in intercourse, and were also less likely to have sexual difficulties after the age of 50. What is clear is that few though these studies are, they all show that circumcision is sexually beneficial.
Deaf to the benefits
I have a cochlear implant and have benefited enormously. Why are people like me never given a voice to set against the genocide-invoking whingeing of the “deaf community” (25 November, p 16)?