Ingersoll was not interested in genealogy. But his wife's family was known and renowned for their unorthodox religious views. Eva Parker Ingersoll was a rationalist and a strong influence on her husband's freethought evolvement. Eva Parker Ingersoll was also an excellent cook, and when Ingersoll travelled from Peoria to small communities to argue cases in the early years of their marriage, he missed the comforts of home. Although Ingersoll's lectures were long, two or more hours, and flowery, in the fashion of the day, his letters contain some oneliners and trenchant comment.
All religions are inconsistent with mental freedom.
Shakespeare is my bible, Burns my hymn-book. I do not borrow ideas. I have a factory of my own. I do not believe in putting out the sun to keep weeds from growing. There is a great difference between fear and prudence.