  Error, the antithesis of knowledge, is the only intellectual impediment to free, philosophical thought. From this principle, Rosmini concludes that assent to erroneous prejudices, not assent to prejudice as such, is the principal obstacle to be overcome by philosophers. Their work consists in examining preconceptions and determining their truth in order to provide grounds for rational persuasion about what they know. To maintain, as many do, that the possession of some unproven truth is inimical to philosophical thought is tantamount to requiring nil knowledge in the prospective philosopher. Rather, a person who knows something, but has not yet come to grips with the reasons leading to it, is like a person who knows the answer to a problem, but still has to consider the reason for the answer. In this case, freedom is not constrained. The point at issue, therefore, in the case of religion, is not that Christians, or Buddhists, or Muslims, or any other religious persons, are necessarily hampered by their beliefs, but whether these beliefs are true, and to what extent they are true. It is not sufficient to state simply that only persons who are devoid of any belief are capable of philosophising freely. Rather