The case against those who see Objectivism as a closed system has been mounted within the ranks of Objectivists. Indeed, the very terms “open” and “closed” systems were coined in a published exchange I had with Leonard Peikoff in 1990, and the battle has been raging for years between the orthodox and the independent wings of the Objectivist movement. Fortunately, there are now many of us in the latter wing. Readers following this thread may be interested in my account of the issues, The Contested Legacy of Ayn Rand: Truth and Toleration in the Objectivist Movement (http://www.atlassociety.org/David%20Kelley%20-%20Truth%20and%20Toleration.pdf). Chapter 5 in particular points out the many ways in which the “closed-system” model contradicts the Objectivist epistemology (pp. 73-85 in the PDF file).
David Kelley, founder & senior fellow, The Atlas Society