A brief reflection about our world (1/2)

Philosophers from all times tried to solve the big universal philosophical problems; i.e. the universe and the nature, mathematics and science, perceptions and beings, and all the other moral questions such as the good, the evil or the justice.
But in the same way they dealt with all those crucial themes, they also always commented the contexts of their eras and their lands. On different levels, they stood up against the systems they knew; some of them paid it even with their lives.