British economist Thomas Malthus (1766-1834) developed theories of population growth which held that if unchecked, human population will rapidly outstrip the resources capable of sustaining it. This way of thinking relies heavily on statistical projections of past trends, disallowing the propensity of human groups to rapidly change.
Malthus was wrong. Over and over again he was wrong. No other prophet has ever been proved wrong so many times. In fact he had it backward. More mean more necessity, more challenge, more creativity, more opportunity for resource development.
The idea that we might grow too big can be disproved only for the moment – never for good. We might always be on the threshold of a special time, when the mechanisms that have kicked in so far stop working. It is true that Malthus was wrong when the population doubled from 750 million to 1.5 billion. It is true that Malthus was wrong when the population doubled from 1.5 billion to three billion. It is true that Malthus was wrong when the population doubled from three billion to six billion. Will Malthus still be wrong fifty years from now?