Short answers, pulled from the story.
Plato declared that changing the musical modes of a state would cause a wide-scale social revolution. He viewed this change as a political imperative rather than an aesthetic preference. Plato believed specific scales could harden the character of soldiers or soften them into submission.
Plato argued that music in the Dorian or Phrygian harmoniai should be encouraged to build courage. He believed these scales could instill a sense of seriousness and stability in listeners. The ancient Greeks viewed these scales as living entities that dictated the ethical state of the listener.
Plato banned the Lydian Mixolydian and Ionian harmoniai for their perceived ability to induce weakness and moral decay. He believed these scales could soften people into submission rather than hardening their character. This decision was rooted in the belief that specific scales dictated the moral fabric of society.
The ancient Greeks did not view these scales simply as collections of notes but as living entities that dictated the ethical state of the listener. This concept known as ethos linked the mathematical ratios of intervals directly to the moral fabric of society. A melody in the Dorian mode was thought to instill seriousness while the Phrygian mode was believed to incite anger and passion.
Plato argued that the choice of a scale was a choice of character within the state. The concept of ethos linked the mathematical ratios of intervals directly to the moral fabric of society. Specific scales could harden the character of soldiers or soften them into submission depending on their type.