A hoard of coins recently unearthed at an ancient Carthagian site bear an image of a face in profile with what appears to be a large mole on the cheek. Pointing out that an artist would be unlikely to include such a specific detail in a generalized portrayal of a face, some archaeologists have concluded that these coins portray an actual individual rather than an idealized type. However, this conclusion is unwarranted, since ________.