Mr. Lincoln was a peculiar man, having a peculiar mind; he was gifted with a peculiarity, namely, a new look-out on nature. Everything had to be newly created for him – – facts newly gathered, newly arranged, and newly classed. He had no faith, as already expressed. In order to believe he must see and feel, and thrust his hand into the place. He must taste, smell and handle before he had faith, i.e., belief. Such a mind as this must act slowly, must have its time. His forte and power lay in his love of digging out for himself and hunting up for his own mind its own food, to be assimilated unto itself; and then in time he could and would form opinions and conclusions that no human power could overthrow. They were as irresistible as iron thunder, as powerful as logic embodied in mathematics.
– – William Herndon as quoted in Abraham Lincoln and the Structure of Reason by David Hirsch and Dan Van Haften, p. 235.