MICHIGAN ACADEMY OP SCIENCE. 
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Rockefellers difficulty arises from the fact that any other method 
of distribution than that which has been contributory to his own suc- 
cesses is inconceivable. But economists ought to be able to see produc- 
tion and distribution at the same time, and in their totality. 
The law of diminishing returns is intimately related to another famous 
and equally archaic economic law, viz.: Malthus’ law of population. 
The substance of this law is that population tends to increase faster 
than the means of subsistence. There is something in this. It works 
in determining the number of wolves, but the last census report does 
not show human population in America confirming it. It is always a 
great satisfaction to find a single principle which will explain a condi- 
tion ; but we are becoming more and more convinced that social phe- 
nomena are the product of numerous forces and are not reducible 
to a single law. Malthus’ law does not care whether a single family 
has many or few children, but whether population is increasing or 
decreasing. So the law of diminishing returns ought not to be limited 
to individual production but extended to production as a whole. It is 
quite true that the surface of the earth is limited in extent, and that 
the population of the earth is multiplying; but it is likewise true that 
the sun is losing its heat, and that sometime the earth will be unin- 
habitable. Any physicist might logically teach his classes the desir- 
ability that the human race accustom itself to the idea of being frozen 
out. But whatever the logic of the question it would and should make 
very little impression on the average healthy-minded individual. Our 
problem presents a very similar situation in which we may justly ques- 
tion whether a healthy-minded person should have any fear about the 
exhaustion of the proper number of food units that may be required, 
even if he is as far sighted as a Conservation Congress. 
Soon after Malthus had written his book, his theory fell into disre- 
pute because of the opening of the great interior plain of the United 
States. But thinkers soon saw that the principle was just as true as 
before, though the pressure of conditions was temporarily postponed. 
But now that we have come practically to the end of free land we seem 
to be nearer than ever to the threshold of the catastrophy. Even such 
a good thinker as Joseph L. Lee the Boston philanthropist feels it for 
in speaking about immigration he says “America is not infinitely large. 
It will in any case— -in what, compared with the long future, must be 
regarded as a verv short time — become so crowded that anv further in- 
crease of the population — except at a comparatively slow rate can be 
made only at the cost of lowering the general standard of prosperity.” 
Land, however, is only one of the three factors in production. The 
incalculable additions to labor and capital in the last generation are 
so much greater contributions than more land could be that we are 
getting farther and farther away from, rather than nearer to the cat- 
astrophy. To return to the analogy of the sun’s heat: it is of course 
true that the sun cannot continue to give off heat forever and remain 
as hot as before. But we have an interesting condition arising from 
the fact that though the sun is radiating its heat and thus diminish- 
ing its potential energy, yet the process of contraction which is taking 
place within the sun causes it to generate heat as rapidly as it is losing 
it, and while this is not a perpetual motion machine, for the purposes 
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