Abraham Lincoln remains alive to us these days, in part because of the extraordinary performance by Daniel Day Lewis in the film Lincoln. In one thoughtful scene, Lincoln sits in a teletype office and wrestles with the question of human and racial equality and the awful institution of slavery. He harkens back to one of the great foundational texts of western civilization, Euclid's Elements, a beautiful book of elementary geometry written over 2,000 years ago.
In the film, Lincoln cites Euclid's first common notion: "Things which are equal to the same thing are equal to each other." He calls it true "because it works, always has done and always will do." And then he reminds us that Euclid called it "a self-evident truth", putting us in mind of another great work of civilization, America's own Declaration of Independence: "We hold these truths to be self-evident: that all men are created equal, that they are endowed by their creator with certain unalienable rights, and that among these are life, liberty, and the pursuit of happiness."
Lincoln, self-educated, a versatile and critical thinker, questioned prevailing assumptions of his day, and, in his search for truth, drew upon mathematical axioms as a storehouse of principles he might apply to his political philosophy. This is what liberally educated people do, people who are broadly and deeply educated in the great movements of history, in the foundational texts and fundamental insights of physics and philosophy, literature and biology, music and theology, sociology and yes, mathematics -- people who have acquired a kind of worldly wisdom that allows them to rise above and see behind the barriers to understanding and action, and take the imaginative leap that is often necessary to solve a problem or find a solution. These are also the people who have developed the skills of listening attentively, speaking persuasively, arguing logically and working collaboratively to bring an idea to fruition.