> E.g. if consumer prices at time A and B are the same, but the value of GOOG is X at time A and 2X at time B, doesn't the dollar at time A has more buying powe

> E.g. if consumer prices at time A and B are the same, but the value of GOOG is X at time A and 2X at time B, doesn't the dollar at time A has more buying power than at time B? To me, this seems like a misleading framing. When you say "consumer prices at time A and B are the same", you can point at a basket of concrete goods which we can agree are the same (a dozen eggs, a gallon of gas, etc). But if the value of GOOG is 2X at time B ... are shares the same? How would you know? Does GOOG at time B have more revenue or a different revenue growth trajectory, or is the competitive landscape different at time B, or did they buy a bunch of other firms? Absolute vs relative is not quite the right distinction, but a share is a portion of a whole whose value can change, and so not a clear unit for evaluating purchasing power. Perhaps slightly more concrete, shares of a REIT are going to change over time, but that can be because the stuff being held changed (they bought more property) or because the value of the stuff they already held changed.