4 ideas
He then lived modestly, supported by grinding optical lenses. He turned down a professorship at Heidelberg to protect his freedom of thought, and died at 44 of lung disease likely worsened by glass dust, with his Ethics published only after his death.
In Durant's paraphrase of Aristotle, virtue is not a single choice or an inborn trait. It is a disposition built up by repeating actions until they become second nature: we become just by doing just acts. As Durant puts it, 'we are what we repeatedly do,' so character is the accumulated result of routine behavior rather than of intentions or occasional heroics.
Philosophy works on questions that cannot yet be answered by measurement, such as values, ends, meaning, and the whole picture. Science is the captured territory, where methods for exact answers already exist. Once a question becomes answerable by experiment it leaves philosophy, which explains why philosophy seems never to 'progress': its successes are handed off and renamed.
Plato divides the soul into appetite, spirit, and reason, and gives the ideal state three matching classes: producers, auxiliaries (soldiers), and philosopher-guardians. Justice, in both the person and the state, means each part doing its own work, with reason governing. Guardians are chosen by merit through education and testing, and they live without private property or family so that self-interest cannot corrupt their rule.