I think it's useful to think if it in terms of how an idea propagates and persists - from person to person, and through the ages. For instance, does it propagate and persist primarily by word of mouth, or by many individuals' separate lived experiences?

Consider the following claim: A dry leaf placed directly in the flames of a wood fire will eventually burn.

That's a claim that pretty much anybody can test. Many people throughout history have been able to put a dry leaf into a fire and see what happens. When I talk about evidence that's widely accessible and democratic, that's what I'm talking about.

To be sure, not everybody has tested this claim for themselves, and so would have to place their faith in other people's memories.

But generally speaking, the reason why most people believe that a leaf will burn in a fire is not because it's a story that's been passed on between generations, but simply because many of us have tested it for ourselves.

That is, the claim propagates and persists by personal experience - widely, democratically accessible and repeatable evidence - rather than through stories and collective memories of bygone events.