One of America's great minds, philosopher and scientist Charles Sanders Peirce (1839-1914) was born on this day in Cambridge, Massachusetts, the son of esteemed mathematician Benjamin Peirce, a founder of the Smithsonian Institute.

"The idea does not belong to the soul; it is the soul that belongs to the idea," young Peirce said.

Inspired by Immanuel Kant and a mentor to William James, Peirce had a passion for logic and exact sciences. A brilliant mathematician and astronomer, he also studied gravity and experimented with pendulums to determine the earth's shape and density.

In the 1870s, he developed the theory of pragmatism: Practical outcome determines the meaning and truth of any idea. Pragmatists celebrate application and process in the transformation of knowledge... And the discovery of truth.

Peirce further explored pragmatism in his well-known essay, Fixation of Belief (1877). To him, thought was a melody and sensations were the notes. The music continues to evolve with time and no symphony is final. "Who can be sure," he said, "of what we shall not know in a few hundred years."

A pioneer of semiotics, the study of signs and symbols, the great thinker left behind over 80,000 pages of unpublished manuscripts. He observed, "The pragmatist knows that doubt is an art which has to be acquired with difficulty."

"Do not block the road to inquiry."