New opinions often appear first as jokes and fancies, then as blasphemies and treason, then as questions open to discussion, and finally as established truths.
So with truth - there is a certain moment when one can say, this is the truth and here I put a dot, a stop, and I go to another thing. A judge has to put an end to a deliberation. But for a historian, theres never an end to the past. It can go on and on and on.
We are always hearing of people who are around seeking after the Truth. I have never seen a (permanent) specimen. I think he has never lived. But I have seen several entirely sincere people who thought they were (permanent) Seekers after the Truth. They sought diligently, persistently, carefully, cautiously, profoundly, with perfect honesty and nicely adjusted judgment- until they believed that without doubt or question they had found the Truth. That was the end of the search. The man spent the rest of his hunting up shingles wherewith to protect his Truth from the weather.
Experience has shown, and a true philosophy will always show, that a vast, perhaps the larger portion of the truth arises from the seemingly irrelevant.
Even as wisdom often comes from the mouths of babes, so does it often come from the mouths of old people. The golden rule is to test everything in the light of reason and experience, no matter from where it comes.