Full Idea
One rule for the justification of knowledge might be: Do not raise the level of scrutiny in the absence of a particular reason that triggers it.
Gist of Idea
A rule of justification might be: don't raise the level of scrutiny without a good reason
Source
Robert Fogelin (Walking the Tightrope of Reason [2003], Ch.4)
Book Reference
Fogelin,Robert: 'Walking the Tightrope of Reason' [OUP 2004], p.124
A Reaction
That won't decide the appropriate level of scrutiny from which to start. One of my maxims is 'don't set the bar too high', but it seems tough that one should have to justify moving it. The early scientists tried raising it, and were amazed by the results.