Carved stone balls are a curious type of artifact found at a number of locations in Scotland. They date from the late Neolithic period, around 4,000 years ago. They are round in shape; they were carved from several types of stone; most are about 70 mm in diameter; and many are ornamented to some degree. Archaeologists do not agree about their purpose and meaning, but there are several theories.
One theory is that the carved stone balls were weapons used in hunting or fighting. Some of the stone balls have been found with holes in them, and many have grooves on the surface. It is possible that a cord was strung through the holes or laid in the grooves around the ball. Holding the stone ball at the end of the cord would have allowed a person to swing it around or throw it.
A second theory is that the carved stone balls were used as part of a primitive system of weights and measures. The fact that they are so nearly uniform in size—at 70 mm in diameter—suggests that the balls were interchangeable and represented some standard unit of measure. They could have been used as standard weights to measure quantities of grain or other food, or anything that needed to be measured by weight on a balance or scale for the purpose of trade.
A third theory is that the carved stone balls served a social purpose as opposed to a practical or utilitarian one. This view is supported by the fact that many stone balls have elaborate designs. The elaborate carving suggests that the stones may have marked the important social status of their owners.
Summarize the points made in the lecture, being sure to explain how they challenge the specific theories presented in the reading passage.