Scientists at Bath University (U.K.) speculate that a universal constructor could increase in numbers exponentially, evolve by Darwinian natural selection, and be reasonable in cost. Such a machine could physically grow by assembling multiple-unit components into something larger. For example, an entire house or building could be built up from many identical components clamped together.
Universal constructors could produce an unlimited variety of consumer and industrial products. It has been suggested that the devices could allow anyone to become a small-scale manufacturer, thus increasing general wealth and reducing the need for massive industrial plants. Self-replicating machines could be a boon to society in general in similarly limitless ways, for example by turning garbage into useful hardware.
Although universal constructors offer the potential of far-reaching benefits, some people fear potential risks, such as unforeseen economic disruption and misuse by people with nefarious intent.