1220 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 2% 
output models it is known that they can be stochasticized in accor- 
dance with this principle (see my report to the Tokyo session 1060 
of the International Statistical Institute). 
LEONTIEF 
In order to understand somewhat better the implications of Pro- 
fessor FrRiSCH’s practical proposals, I would like to ask whether there 
would be an objection against allowing people to trade goods and 
services among themselves at what one might call black market pri- 
ces. In principle at least, the difference between these and the 
official shadow prices would reflect the discrepancy between the 
actual shapes of preference function of consumers and their official 
estimates prepared by the planning authority. 
FRISCH 
I have about ten pages of notes that I have taken during the 
discussion. I will try my best to do justice to everybody, but you 
will understand that this is a very difficult task in view of the long 
discussion and the complicated points at issue. 
One of the Prof. Arrais points was that we are discussing the 
econometrics of the future and in this connection he said that econo- 
metrics should be neutral. Everything, of course, hinges upon what 
is meant by neutral. You know that for centuries there has been a 
tendency to define neutrality in economics by saying that any ana- 
lysis which takes the free market system as an axiom, is « neutral », 
but any analysis that has the audacity of questioning the free market 
system is not « neutral », but « political » and should therefore not be 
allowed to enter into the ivory tower of the scientist. This has been 
the situation in economics for a couple of hundred years but this is 
not the situation any more. Today we have to recognise the fact that 
there are also other economic system that are « in the air » and must 
be discussed by us as social engineers. I must add that not only 
17] Frisch - pag. 24