Samuelson's random-walk analogy for stock prices was mathematical showing-off dressed up as a claim about the real world.

Drawn from what Andrew Gelman said, then moved away from

What this subject means

stock market Equities as a whole: what returns have been, whether prices carry information, and what attention does to them.

What Andrew Gelman actually said

Holders over time

Do you hold this korrent?Do you also believe this?

Shared subject first, then similar wording. They may agree or disagree.