1. we should not accept a belief as true if there is a preponderance of evidence against it, or if it is found to be rationally inconsistent with other well-founded beliefs, or both. To cling to beliefs for which there are abundant evidence and reasons to the contrary is irrational. Another application of this rule is reasonable, that is,
"The naturalistic outlook is first and foremost a commitment to a distinctive method of inquiry. The term inquiry refers to the evaluation of belief claims, many of which are largely unexamined in contemporary society-particularly basic beliefs. Many modern thinkers have argued that we should examine our beliefs and theories carefully and assent only to those for which there are adequate grounds. Wherever possible, inquiry should provide rational guidelines for thought and conduct.
Skepticism is an essential aspect in this process of inquiry, and it contributed to the development of reliable knowledge. It is used effectively within the sciences. The basic premise is that we need to question our beliefs, particularly those that are central to life, to see if they are well grounded by reason and evidence. We do so in order to advance human knowledge and enhance life. Bertrand Russell held "that it is undesirable to believe a proposition when there is no ground whatever for supposing it true." He thought that this doctrtine appears to many people to be "widely paradoxical and subversive," for if consistently applied it would overturn some of the most cherished beliefs and sacred cows of society. At the very least, one might agree with Russell's recommendations:
2. that we ought not to accept a belief as true if there is inadequate evidence and insufficient reasons to do so, and conversely,
3. we should accept a belief claim only if it is based on adequately justifying reasons and sufficient evidence. A corollary of this is that
4. where we do not have adequate grounds for believing that something is the case, then we should, wherever possible, adopt the stance of the skeptic and suspend judgment. Reason also dictates that
5. we should always leave the doors open to further inquiry; we should not censor or block the objective examination of truth claims, and any belief claim that is accepted on adequate reasons and evidence should not be insulated from further inquiry."
....more, at cfi