As the dust of the Second World War began to settle, that which began life in the U.S. as an experimental space in early twentieth century firms became a knowable object of intervention for economics and accountancy alike. Jumpstarted by the war, research and development, or RandD, was pulled into the experimental forays of a new generation of experts, including macroeconomic growth theorists. By explaining growth outputs in terms of RandD inputs, postwar macroeconomists failed to learn the lesson that was so hard won by accountants, namely: that it is the very uncertainty of outcomes which makes experimental inquiry so valuable to society and yet so untenable as capital.