SECTION F.—ECONOMIC SCIENCE AND STATISTICS. 
THE CHANGED OUTLOOK IN REGARD 
TO POPULATION, 1831-1931. | 
ADDRESS BY 
EMERITUS-PROFESSOR EDWIN CANNAN, M.A., Litt.D., LL.D. 
PRESIDENT OF THE SECTION. 
Times change, and economic theories change with them. We need no 
longer be ashamed of the fact, as we used to be inclined to be in the old 
days, when our colleagues in other Sections of the Association professed to 
despise us for disagreeing among ourselves and perpetually overthrowing 
conclusions arrived at by our predecessors. We hear less now of the 
certainty and finality of the other sciences, and can face their exponents 
unabashed, confident that theories may be useful for leading us on towards 
the truth without being immutable and exempt from revision. 
I think that the biggest change made in economic theory during the 
last hundred years is to be found in the treatment of the subject of 
Population. In 1831, Malthus was still alive, and quite unrepentant for 
the shock he had given the public thirty-three years earlier by his Hssay 
on the Principle of Population as it affects the future Improvement of Society. 
No one, it is true, any longer attached much importance to his doctrine of 
the inherent incompatibility of the ratios in which it was possible for 
population and food to increase, but the disfavour with which he regarded 
what he considered the natural tendency of population to increase was 
shared by most of the economists of the orthodox school, who had adopted 
the theory of diminishing returns to agriculture which was evolved in 
England from the local conditions of the very ‘short period’ of the 
Napoleonic war. 
That theory, not as now taught in a form which makes it innocuous, 
but as taught in the early years of the nineteenth century, purported to 
show that the natural limitation of fertile and well-situated land must 
necessarily mean that the more numerous the people, the more difficult it 
must be for them to feed themselves. It was admitted that there were 
counteracting circumstances, summed up as ‘ the progress of civilisation,’ 
which, in fact, had throughout history prevented the growing population 
of the civilised woxld from actually finding it more difficult to feed itself, 
but these circumstances were regarded as making only temporary headway 
against the general tendency, and not, like it, as being a law of nature. 
J. 8. Mill, in his Principles of Political Heonomy with some of their Applica- 
tvons to Social Philosophy, which, though not made into a book until 
seventeen years after, was really thought out before 1831, and represents 
the ideas of 1800 to 1830 better than any other work, even ventured to 
