520

PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28

troduced in the form of a « rate of technical progress », which
has been treated exactly like, and svmmetricallv to. the rate
of population growth (?).
Unfortunately, this approach has been accepted rather uncritically
 so far. It is my purpose to criticize and abandon it.
But before doing so, I must invite the reader to take a closer
look at all the implications that this approach entails. Our
disaggregated formulations will turn out to be very useful in
this task.
As said above, any macro-economic analysis implies that
all variables considered are measured in terms of a composite
commodity or « basket of goods » of fixed and invariable composition
 through time. Therefore, unless the macro-economic
framework is given up altogether, the introduction of a rate
of technical progress in such an analysis necessarily implies
two further and much more specific assumptions: 1) that technical
 progress is going on at the same rate in all sectors of the
economy; and 2) that demand for each product is expanding
at the same rate.
Let us carefully consider a hypothetical case of economic
growth in which these two assumptions are satisfied.

theory. The first type of models is perhaps best represented by: J. Ro-BINSON,
 The Accumulation of Capital, London, 1956, and N. KALDOR,
A Model of Economic Growth in « The Economic Journal », 1957. The
most representative examples of the neo-classical models are perhaps:
R.M. SoLow, À Contribution to the Theory of Economic Growth in « The
Quarterly Journal of Economics », February, 1956; and J. Meape, 4 Neo-Classical
 Theory of Economic Growth, London, 1961.
(*) In the present and following chapters, we shall normally consider
percentage, i.e. relative rates of change. However, for brevity’s sake, and
following what has by now become a custom, in economic literature, the
words percentage or relative will normally be omitted, except in those
cases where their omission may generate misunderstanding.

10} Pasinetti - pag. 50