IELTS Academic Reading Practice Test 193

Of all the devices people wear on their bodies, the contact lens is among the least visible and the most precisely engineered. Its history begins with a notebook. Around 1508 Leonardo da Vinci sketched ways in which the optics of the eye might be altered, including a drawing in which the front of the eye is covered by a layer of water. Leonardo was not trying to make a lens that could be worn; he was exploring how the eye forms an image. Yet the principle he illustrated, that changing the surface at the front of the eye changes the way light is bent, underlies every contact lens made since.

The first person to propose a device that would actually sit on the eye was the French philosopher René Descartes. In a book published in 1637 he described a glass tube filled with water and closed at one end with a curved piece of glass, which the wearer would hold against the eye. The curve of the water-filled tube would correct the bending of light entering the eye. The scheme could not work in practice: the tube projected far from the face, and the eye could not blink while it was in place.

In 1801 the English scientist Thomas Young held a small water-filled tube against his own eye in order to study how the eye focuses; he was not attempting to correct his sight. Some two decades later, in 1823, the astronomer John Herschel suggested that a lens might be moulded to follow the curve of the eye itself and filled with a clear jelly. The idea anticipates the soft lens by more than a century, but neither man built such a device.

The decisive year was 1888, when three men working independently produced the first contact lenses that were actually fitted to living eyes. Adolf Fick, a German-born physician working in Zurich, made blown-glass shells that covered the whole front of the eye. In Paris the ophthalmologist Eugène Kalt made similar lenses while trying to help patients whose cornea had lost its regular curve, and a German student named August Müller, who was severely short-sighted, ground a glass lens for himself. These were scleral lenses: they rested on the sclera, the white of the eye, rather than on the cornea. They were heavy, they trapped tears beneath them and they cut the eye off from the air, so they could be worn for only an hour or two.

For the next four decades, contact lenses remained an object of medical curiosity. Each had to be made to fit an individual eye, and without a standard method the shape was often derived from an impression taken of the eye's surface. Because glass shells had to be blown by skilled craftsmen, the lenses were expensive and fragile, and they were available only to a small number of patients, most with damaged eyes rather than ordinary poor sight.

The material that changed this arrived in the 1930s. Polymethyl methacrylate, usually known as PMMA or acrylic, was a transparent plastic that could be shaped far more easily than glass and did not shatter. Practitioners in Europe and the United States, among them the German optician Heinrich Wöhlk and the American optometrist Theodore Obrig, began to make scleral lenses from it. In 1948 an American optician, Kevin Tuohy, was turning a PMMA lens on a lathe when the outer portion separated from the centre, leaving a small piece that covered only the cornea. Tuohy fitted it to a patient and found that it worked, and within a few years the corneal lens had replaced the scleral type for most purposes.

The second great change came from a laboratory in Prague. In 1960 two Czech chemists, Otto Wichterle and Drahomír Lím, reported the synthesis of a hydrophilic polymer, a plastic whose molecules attract and hold water. Dry, it was hard and clear; once swollen with water it became soft and flexible, much like living tissue.

Wichterle saw at once that such a gel might be moulded into a lens that would float on the film of tears covering the eye. The first soft lenses were produced in 1961 with an apparatus assembled from a child's building set and parts of a bicycle dynamo. A licence was sold to Bausch & Lomb in 1965, and soft lenses went on sale in the United States in 1971.

Soft lenses were comfortable from the moment they were put in, but the early hydrogel materials were poor conductors of oxygen. A lens covering the cornea for many hours could starve it of the gas it needs. In the late 1970s manufacturers introduced rigid lenses made from materials that oxygen could pass through, and in 1999 a new class of soft material, the silicone hydrogels, combined the water content of a soft lens with the permeability of a gas-permeable one. Approval for continuous wear followed in the United States in 2001.

The most recent chapter is about replacement rather than invention. From the late 1980s, when disposable lenses were introduced, wearers were encouraged to throw lenses away after a fixed period rather than clean and store them for months. Daily disposable lenses, discarded every evening, are now the most widely used type in many countries. More than a hundred million people wear contact lenses today, and although the materials and the manufacturing methods have changed out of recognition, the essential idea is still Leonardo's. Place a shaped, transparent surface at the front of the eye, and the world comes back into focus.

A heat pump does not generate heat; it moves it from one place to another, in the same way that a refrigerator moves heat out of its interior and into a kitchen. The ground beneath our feet is a vast reservoir of low-grade heat, warmed by the sun and by the Earth's own interior. At a depth of a metre or two its temperature stays remarkably constant throughout the year, close to the average air temperature of the region — around ten to fourteen degrees Celsius across much of Europe. A ground-source heat pump exploits that stability: it extracts heat from the soil or from groundwater and delivers it, at a higher temperature, to the radiators or underfloor pipes of a building.

The device works through a cycle of evaporation, compression, condensation and expansion, using a fluid known as a refrigerant. In the evaporator, a coil buried in the ground or lowered into a borehole, the refrigerant is held at a low pressure so that it boils at a temperature below that of the surrounding soil. Boiling absorbs heat, and the vapour that forms carries that heat away. A compressor then raises the pressure of the vapour, which also raises its temperature sharply. In the condenser this hot gas gives up its heat to the water circulating in the building's heating system, and in doing so it condenses back into a liquid. Finally an expansion valve drops the pressure again and the cycle repeats.

There are several ways of connecting a heat pump to the ground. The cheapest, where there is space, is a horizontal loop: lengths of pipe are laid in trenches about a metre and a half deep. A house with a small garden may instead need vertical boreholes, drilled to depths of between fifty and a hundred and fifty metres, which cost considerably more but disturb very little of the surface. Where a pond or a lake is available, coils can simply be weighted and sunk in it. A fourth option, the open-loop system, pumps groundwater from one well, extracts heat from it and returns the water to another.

The attraction of the technology lies in its efficiency. A well-designed system typically delivers three to five units of heat for every unit of electricity consumed by the compressor and pumps, a ratio expressed as the coefficient of performance. Because the ground stays at about ten degrees even in midwinter, while the outside air may fall below zero, a ground-source pump works less hard than the air-source machines that have become common in many countries. Efficiency also depends on the temperature at which heat is delivered: the lower it is, the better the pump performs, which is why underfloor heating suits the technology so well.

The idea is older than is often assumed. The principle of the heat pump was described in the middle of the nineteenth century, and experiments with ground-coupled systems were carried out in the United States in the late 1940s. For decades, however, cheap oil and gas kept the technology marginal. Its growth came with the oil crises of the 1970s, when Sweden and Switzerland began to encourage it, and it has accelerated in the past twenty years as governments have looked for ways to heat buildings without burning fossil fuel.

The obstacles are mainly financial and practical rather than technical. Drilling boreholes or excavating trenches can account for a large share of the total cost, and although running costs are low, the payback period may be a decade or more. The system also needs somewhere to put the loop, and a building whose walls and windows leak heat will waste the benefits unless it is insulated first. A further difficulty concerns the ground itself. In a heating-dominated climate, heat is steadily drawn out of the soil through the winter and only partly replaced by the sun and by conduction from the surrounding rock; where a system is badly designed, the ground can cool over successive seasons and performance falls.

Research is therefore directed at making the ground loop cheaper and more effective. One approach is the hybrid system, which pairs a smaller ground loop with a conventional air-source unit or a solar collector. Another is seasonal storage: rather than extracting heat only, some schemes collect solar heat in summer and inject it into the ground, raising the temperature of the soil or rock so that it can be drawn on in winter. A district in Alberta, Canada, has used this principle to supply most of the space heating for a small community, and several European towns are experimenting with similar systems built around boreholes hundreds of metres deep.

Governments have begun to treat the technology as part of the shift away from fossil fuels. Heat pumps are eligible for subsidies in many countries, and the European Union has set targets for their installation. The electricity they use must of course be generated somehow, and the carbon savings depend on how clean the grid is: a heat pump running on coal-fired electricity may emit little less than a modern gas boiler, while one drawing on a grid with a large share of renewables or nuclear power can cut emissions sharply. Utilities are also interested in the flexibility that heat pumps offer, since a well-insulated building can absorb heat for an hour or two while demand on the grid is high.

For all the engineering involved, the appeal of the ground-source heat pump is simple. It takes the modest, reliable warmth of the soil and concentrates it where people live, using a fraction of the energy that burning fuel would require.

The question in the title sounds like the stuff of science fiction, but it is now asked in earnest, in ethics committees and insurance offices and, in 2017, in the European Parliament. Robots already perform surgery, drive trains, care for elderly people and talk to lonely children. As they become more autonomous, the laws that govern responsibility for what they do look increasingly inadequate, and it is not surprising that someone should have suggested giving the machines themselves a legal status. Whether that amounts to giving them rights is another matter, and one that requires more care than it usually receives.

The argument for doing something is straightforward. When an autonomous machine injures someone, the existing categories fit badly. A surgeon is responsible for an operation, and a manufacturer for a defective product, but a system that learns from data and makes decisions its makers did not anticipate falls between the two. In a resolution adopted in early 2017, the European Parliament called for new rules on liability for robots and raised the possibility that the most sophisticated autonomous machines might be given a special legal status, described in the accompanying report as electronic persons. The aim was not to flatter the machines but to ensure that someone, or something, could be held accountable and could pay compensation.

The reaction was swift. In April 2018 an open letter objecting to the idea of electronic personhood gathered signatures from more than a hundred specialists in robotics, artificial intelligence and law. Their objection was not merely that the proposal was premature. It was that creating a legal category of machine person would let the humans who design, manufacture and deploy robots off the hook. If the robot is the person, then the robot is responsible, and a company that has built a machine whose decisions nobody can explain may find that it has nothing to answer for.

On the narrower question of moral rights, the case is weaker still. Philosophers have disagreed for centuries about what grounds moral consideration, but the most widely accepted answer is sentience: the capacity to have experiences that matter to the being that has them, and in particular to suffer. No machine built so far comes close. A system that says it is frightened, or that begs not to be switched off, is producing sentences that its training has made statistically likely in that context; there is nobody at home to be frightened. To grant rights on the basis of such behaviour would be to confuse the simulation of feeling with feeling itself.

None of this means that the legal concept of a person is useless here, because lawyers use the word in a narrower sense. A company is a legal person: it can own property, sign contracts and be sued, although it has no feelings at all. Giving a machine a limited legal personality, restricted to particular transactions such as holding an insurance policy or registering with an authority, is therefore not absurd. It is a technical device for organising who pays when things go wrong. The danger is that such a device is exactly what manufacturers would like, since it can limit the money available to an injured person.

The more serious ethical questions, in my view, run in the opposite direction. They concern not what we owe to robots but what robots do to us. People form attachments quickly to machines that seem to respond to them, and manufacturers know it. A robot that a child treats as a friend is also a device that records what the child says; a companion for a lonely pensioner is a listening post in the living room. Research on how these attachments develop is in its infancy, and there is a reasonable case for regulating the design of machines that are intended to be treated as though they had feelings.

There is also a risk that the language of robot rights distracts attention from harms that are already here. Algorithms now help to decide who is offered a mortgage, which applications reach a human reader and how long a prisoner stays in jail, and the people affected are not machines. Debates about electronic personhood have little to say about any of this. Worse, they supply a vocabulary in which responsibility can be quietly dissolved: if a system made the decision, then nobody did.

So where does that leave the question in the title? My answer is that robots should not be given moral rights, and that the case for treating them as full legal persons is unconvincing. A narrow and revocable legal status, tied to compulsory insurance, registration and an identified human being who remains accountable, is a different proposition, and may be worth having. That is not a matter of kindness to machines. It is a way of keeping our obligations to one another in clear view.

A comparison sometimes drawn with the granting of legal personhood to a river in New Zealand is instructive but does not help the robots. The river was given a status so that the community that depended on it could be represented and could take action against those who polluted it. The rights served people. A machine that is given rights only so that its makers can escape them serves nobody but its makers.