"In the absence of perfect certainty, the futures prices needed for making the requisite wealth-like comparisons are simply unavailable. So it would be difficult to make operational the theorist’s desired measures. But operational practicality aside, if the theorist specifies in detail the dynamic technology of his model, he will meet none of the pitfalls that come from an attempt to summarize his model by various crude aggregations. The contradictions that result from over-crude aggregation should never be confused with the technical relations that hold at the firm and family level or with the market capitalizations which hold in competitive security and asset markets."