Final answer:
We know little about ancient music because hardly any written notations have survived, though ethnomusicology provides some insights.
Step-by-step explanation:
We know little about the music of very ancient civilizations primarily because hardly any notated music has survived from these cultures. Prehistoric peoples used music to communicate, tell stories, and express cultural elements, but the lack of written documentation means that much of the music's specific forms and practices have been lost to time. The study of ancient musical instruments and ethnomusicology offers some insights into the musical artifacts of these societies, suggesting a richness in culture and technology that was akin to modern advancements in music creation and performance. However, without surviving notated examples of their music, it's difficult to fully understand the artistic nuances and theoretical foundations that defined their musical heritage.