034 
PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 
Here, once more, traditional theory has taken up only a limited 
case to study. It has always assumed that individuals know 
their preferences perfectly and behave rationally. There is of 
course a justification for such an approach in a static environ- 
ment, but no longer in a dynamic world. We do positively 
know that human beings are not omniscient, and that the way 
in which they come to know new situations is through expe- 
rience. They may know reasonably well the problems faced 
already in the past; for they have had the opportunity of 
trying and experimenting with different solutions. But if a 
new situation arises, they have first to learn how to deal with 
it, and the decisions they make the first time may not be the 
best ones — they are tentative decisions in order to learn. 
Now, if real per-capita income is continually rising, each con- 
sumer enjoys an extra amount of income to spend in each 
successive period, which indeed puts him in a new situation. 
Especially when incomes become high, to pretend the con- 
sumer makes the best decision — according to his preferences — 
about the extra income he has just obtained is unreasonable. 
He does not know his preferences at that high level of income, 
because he never experienced them before — he has to learn 
them. This is not all. As time goes on, the quality of old 
goods may change, and the price structure may also change; 
while old needs may be satisfied with better (superior) goods. 
This means that the consumers’ learning activity is a process 
required over the whole range of his preferences. As a con- 
clusion, I should like to propose here to enlarge our views of 
consumers’ behaviour and to complete the traditional postulate 
« the consumer is a rational being » with the more general one 
« the consumer is a learning being ». The latter is more ge- 
neral because it can be regarded as including the former as a 
particular case: the case of a stationary economic system. (In 
such a system technology and income have, by hypothesis, 
always been constant through time, which means that all learn- 
ing activity has been completed already in the past. Since 
T10] Pasinetti - pag. 64