What did Robert Ingersoll believe in?

Will you give me some fact known only to you and Mrs Ingersoll by which she may know that you still live?

Dear Sir & Friend

Report my visits to my wife. I entertained privately the opinion during my earth life, most strange to many I presume, that a certain deception, harmless in its result, was justifiable. 

For instance, the subject of immortality of the soul and truths of modern spiritualism. 

Privately, I held the hope of their truth―the line separating them was difficult to determine. My deception if it may so be termed was committed in the unspoken realm of thought I entertained. 

Mrs Ingersoll knew well my mental attitude while the world did not. I refer to this as subtle evidence to her that I am writing. I am, of course, living, were it not, I could not write this.

—Spirit R. G. Ingersoll