alu 
DORFMA} 
{ feel very strongly moved to express my admiration ‘mn 
Prof. KCOPMANS’ paper. As Dr. JoHNSON might have said, its pic 
fundity is equalled only by its ingenuity. And it reaches some re 
markable and exceedingly significant conclusions. 
[t is important to point to two quite strong assumptions on 
which the conclusions rest. One of them is that Prof. KooPMANS has 
replaced the three factors of classical economics — land, labour and 
capital — by a two factor model. He omits land. The technical 
effect of introducing land into Prof. KooPMANS’ model would be to 
change one of the essential mathematical functions. Since land is 
in virtually fixed supply, it would no longer be permissible to think 
of constant returns to scale to the two variable factors. I can only 
conjecture the consequences of that change, but perhaps it would 
strengthen the moral case for saving on the part of the present ge- 
neration because they will be better endowed per capita with the 
third factor than future generations if population continues to grow. 
The other strong assumption made by Prof. KooPMANS is that 
capital does not depreciate. I think it was RICARDO who originally 
defined land to be the original and indestructible powers of the 
soil. We have since generalized this concept to mean the original and 
indestructible power of anything that we inherit. The findings 
of capital theory indicate that if either of those two adjectives is 
4+] Koopmans - pag. 65