Today, Benjamin Franklin and Cotton Mather. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Benjamin Franklin was Colonial America's famous liberal rebel. Cotton Mather was the archetypical conservative Puritan leader. Like Mather, Franklin started out in Boston. They made unlikely bedfellows, yet when Franklin was eleven, he read Mather's book, Essays to Do Good. It had a lasting impact on him, and through his vast influence it has, ultimately, touched us as well.

Ben Franklin's older brother James was a printer and the publisher of the New England Courant. James went after Mather on many issues -- most stridently during a 1721 smallpox epidemic. Mather was promoting the unheard-of practice of inoculation, which he'd learned from his African servant. (The idea of averting disease by subjecting yourself to it was a very hard sell.)

Ben had served as James' apprentice during those times. Then, at seventeen, he found work as a journeyman printer in Philadelphia. He's been associated with that city ever since. After a year he returned to Boston for a visit, and the first thing he did was a surprise. He went to visit Cotton Mather.

Mather made no mention of the earlier attacks by James, and he received Ben graciously. Historian I.B. Cohen tells how, as Franklin was leaving, Mather shouted at him, "Stoop, stoop!"

Too late! Franklin struck his head on the low doorjamb, and Mather intoned: "You are young, and have the world before you; stoop as you go through it, and you will miss many hard thumps." Franklin did not miss the point. Later he said, "I often think of [Mather's words] when I see pride mortified, and misfortunes brought upon people by their carrying their heads too high."

The clergyman Mather also influenced Franklin the scientist. He wrote about spontaneous hybridization in plants. He wrote a treatise on medicine. Mather was an empiricist who called "the incomparable Sir Isaac Newton" his guide in science.

And so young Ben Franklin worked out his ethics by turning Mather's advice into the more compact and secular language of Poor Richard's Almanac. In an exhortation on service to the kingdom of God, Mather said that it means redressing "the miseries under which mankind is languishing." Poor Richard summarized that one in the words: "Serving God is doing good to man, but praying is thought an easier service, and therefore more generally chosen."

But Franklin didn't just preach. He followed Mather's advice and acted as well. In 1751, a Dr. Thomas Bond said that Philadelphia needed a hospital. That was radical. The Colonies had never seen a hospital. Franklin combined his skill as a printer, his passion as a social activist, and the guile of a superb fundraiser. He gave America its first hospital.

There's a wonderful lesson here. Franklin and Mather were stereotypical opposites, yet the best of each is woven into America. They are a wonderful reminder that we all need to keep weighing, sifting, and reassessing our own indignations. I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work. (Theme music)

Cohen, I. B., Benjamin Franklin's Science. Cambridge, MA: Harvard University Press, 1990. Chapter 10.