Walking Blindly Towards Disaster?
Do you wear glasses? I do. I’m also willing to bet that you know several people who do too. In fact around half of the British population is short-sighted1. Is there something strange about the fact that a significant proportion of people have to wear glasses in order to see properly? Are humans the only ones that suffer from this problem? The answer to this last question is almost certainly ‘yes’, and the reason why is Darwin’s.
Although Darwin’s theory of evolution is well known I will explain briefly how it might apply in this case. Given that an animal has eyes it may be concluded that those eyes are advantageous to its survival, otherwise they would not have evolved. Therefore, assuming that the environment in which the animal lives is not greatly different from that which its ancestors lived in, if the animal happened to be born with eyes less good than the others in its species it would have a reduced chance of survival and therefore of passing on its poorer eyes to future generations. Thus we may conclude that poor eyesight would not tend to become common in an animal population. This is exactly what is observed in nature; animals born with poor eyesight are rare and the ones that are don’t often last long.
Why then is the situation different for humans? The answer is now obvious; while animals are greatly disadvantaged by poor eyesight, perhaps in activities such as catching prey or avoiding predators, humans have no such problems; they are less troubled by such struggles for survival and, at any rate, the problem can be easily corrected by wearing glasses. A human born with poor eyesight, or who develops it later in life, hardly worries that it might affect her future chances of survival or reproduction.
We have, it seems, discovered an interesting phenomenon: the problem for which glasses are intended to be the solution becomes prevalent simply because glasses exist. It can hardly be the case that 1000 years ago half of the population suffered from myopia. It would have been a society full of useless invalids. But when glasses were invented in the thirteenth century2 the problem was removed and those who suffered from short sightedness could function normally, presumably increasing their chances of reproduction and passing on their genetic defect. This is an example of what a biologist would call selection pressure; the selection pressure towards good eyesight keeps animals, and kept our ancestors, from evolving poor eyesight, but glasses remove this pressure and therefore allow poor eyesight to develop.
So we have discovered the reason why so many people wear glasses. ‘But what of it?’ you may ask. Society certainly does not seem to suffer from having some of its members needing to wear glasses and there are now even more effective treatments available — surely we don’t need to worry about the fact that many people aren’t naturally able to see very well. But consider, if this could happen with eyesight why not with any other of our evolved attributes? Modern medicine has developed treatments for many different problems. Joints can be replaced with new ones made from titanium — does this mean that humans of the future could lose the capacity to grow properly working joints and have to have them replaced artificially? Glasses have been around much longer than most effective medical treatments, but in fact degradation of eyesight has occurred remarkably quickly, in around 20 generations. As medical technology develops there is surely no reason why in a few hundred years there won’t be a large number of complaints that are routinely treated by artificial manipulation of the human body for a large proportion of the population.
Taking this argument to its logical conclusion leads to something truly fantastical. What in principle couldn’t be replaced artificially… limbs… a heart… a brain? This conclusion may seem far off, but processes that are leading us towards it are taking place today. At some point this danger will need to be addressed and the sooner, the better.
By Eric Blair
Sources:
1. http://en.wikipedia.org/wiki/Myopia#Epidemiology
2. http://en.wikipedia.org/wiki/Glasses#Invention_of_eyeglasses
Many modern people develop poor eyesight because they ask their eyes to do things that their ancestors did not. Staring at up close computer screens for hours on end, or even reading, takes a toll on the eyes that staring across the savanna did not.
One should probably take into account the simple fact that human evolution is achieved in a much different way than one finds in the animal kingdom. See the book “The Machine in the Garden.”
Basically, humans develop extensions, rather than their body evolving. For example, clothing is an extension of the human pelt, allowing us to exist in climes which would normally be too cold for us. Cars, an extension of our legs, allowing us to travel swiftly from place to place. Books and/or computers, an extension of the human brain, and the list goes on.
If this is the way we develop as a species, then does it really hurt to continue doing so? Especially since we unconsciously value the kind of person who is most capable of pushing forward our development – the inventor/magician/creative thinker. From Connecticut Yankee in King Arthur’s Court to the movie A Bug’s Life, Macguyver to the popular Pirates of the Caribbean series, pop culture and literature is riddled with accounts of people who use resources at hand to pull themselves out of a tight position.
Regrettably, these extensions might make our bodies softer. If it makes our minds sharper, however, then is the danger really as great as you say? Children are now able to operate and even improve upon machinery that their grandparents and great grandparents would never have dreamed of. Considering that, who knows what our great grandchildren will be able to do? I see a bright future, not a dim one.
Or maybe that’s just the light from the computer, reflecting off of my glasses.