What is the function of philosophy?

Philosophy seems to thrive the most during periods of upheaval and seems to have extensive implications for the populace at large. I am thinking about the ancient Greeks and ancient Chinese, both of which flourished during times of war and conflict, and both of which had a great impact on the development of their respective nations. I'd like to highlight ancient China as a good example, as many of the major Chinese philosophies were developed by philosophers who were involved in popular movements and revolutions and who also advised (or attempted to advise) rulers on questions of policy. This was also true for the ancient Greeks as well, as demonstrated in Plato's republic.<br><br>The same movement can be seen in the modern world. The rise of philosophers like Rousseau, Voltaire, and Kant precipitated the enlightenment and the French Revolution, while the rise of philosophers like Marx, Nietzsche, and Freud precipitated the modernist movement. Rousseau's theory of the social contract, Kant's categorical imperative, Nietzsche's will to power, and Marx's dialectical materialism all have had an impact on the way society is structured today.<br><br>In the face of the current political situation, I am asking: what is the function of philosophy? And what role should philosophers play in shaping the world? Philosophers should not be advisors to leaders, nor should they be merely hobbyists. <br><br>The real question is, how do philosophers affect the actions of the common man? How do they do so in a way that is progressive and helps to overthrow the current system?