alt Hacker News> much of it several dozen or thousands of layers of indirection deep
Assuming we're just talking about information on the internet: What are you reading if the original source is several dozen layers deep? In my experience, it's usually one or two layers deep. If it's more, that's a huge red flag.
Let's take a simple claim:
On Earth's surface, acceleration due to gravity is ~9.8m/s^2
I haven't tested this, but here you are reading it.
Did the person who I learned this from test it? I suspect not.
Did the person who they learned it from test it? I suspect not.
Did the person who they learned it from test it? I suspect not.
Did the person who they learned it from test it? I suspect not.
Did the person who they learned it from test it? I suspect not.
...
Did the person who they learned it from test it? I suspect not.
Could anyone test it? Sure! But we don't because we don't have the time to test everything we want to know.