Kant

He believed that being a mature adult meant using your own reason rather than blindly following the dictates of the church, the state, or tradition. This emphasis on (self-governance) transformed political theory and individual identity. 4. Perpetual Peace

rather than consequences. He believed a "good will"—acting out of duty—is the only thing that is truly good in itself. He believed that being a mature adult meant

offers several formulations of this supreme principle of morality. The most famous are two: Perpetual Peace rather than consequences

For , there is only one thing good without qualification: a good will . Intelligence, courage, wealth—these can be used for evil. A good will is the will that acts for the sake of duty , not merely in accordance with duty . The most famous are two: For , there

For decades, locals set their watches by afternoon walks. He left his house at exactly 3:30 PM, walked the same route along the "Philosopher’s Walk," and returned precisely one hour later. The only time this routine broke was when he received Jean-Jacques Rousseau’s Emile —he stayed indoors for three straight days to read it.

This is jewel. You can use a taxi driver to get to the airport (that's a means), but you cannot treat them merely as a tool. You must respect their rational autonomy. Similarly, you cannot use yourself (by committing suicide out of despair) because your own humanity has dignity, not a price.