The Dotted Line

The dotted line is the step in a chain of reasoning where the inputs stop having sources, the assumptions stop being listable and the error can no longer be estimated. Before it, sources and models constrain the result. After it, neither does.

The term is this site's own. Each chain overview switches to a dashed line from that step onward, and the text says it outright: “From here on, we are guessing.”

On the Fermi paradox page, the travel-time sums come before the line. Whether anyone would set out, and keep launching ships for that long, comes after it, because no measurement feeds those steps.

Limits of the term

Crossing the line does not sink a page, and guessing is allowed. The line marks where it begins, so you can stop trusting the arithmetic at the right moment.

Steps after the line are rated Seeing: overcast. The reverse does not hold, because two estimates more than 3 times apart are also overcast and may lie before any dotted line. See How We Rate a Reading.