Two hundred years ago, on February 12, 1809, a pair of cosmic twins entered the universe. Abraham Lincoln was born in a log cabin in Kentucky. Across the Atlantic, Charles Darwin was born on an English estate. When they left this earth they made an everlasting mark on the principles of democracy and human evolution. Writer Adam Gopnik gives meaning and significance to this enduring convergence in his new book Angels and Ages: A Short Book About Darwin, Lincoln, and Modern Life. He joins us now for a celebration of the 200th birthday of two amazing men.