The reading passage states three plausible theories account for the purpose and meaning of carved stone balls which found in Scotland, whereas the professor points out that these explanations are not convincing.
Firstly, the author insists that the balls were used as weapons for hunting and fighting. The speaker, however, argues that the weapons dating from Neolithic period show signs of wear, and if these stone balls were weapons, they should also show those signs. In addition, the balls should be crack and pieces like other weapons found in that period, nevertheless, those balls are well preserved with no significant damage.
Secondly, the reading says that the balls are so uniform in size that they could be used as standard weights to measure quantities. In contrast, the lecture reckons that they cannot be used to measure since they were made of different stone with various weights. Although two balls seem like the same size, they virtually possess varied weights, in this way, they must have other functions.
Lastly, the author states that these balls might possess a social purpose due to their elaborate design. On the contrary, the professor deems that it is not reasonable for them to serve such a purpose, because some balls have intricate patterns while other balls' motif are too simple to present social status. For instance, individual possessing a high-ranking would be buried with his possession, and these balls were not found in any graves. Therefore, they cannot be used to present social status.