 If the earth must lose that great portion of its pleasantness which it owes to things that the unlimited increase of wealth and population would extirpate from it, for the mere purpose of enabling it to support a larger, but not a better or a happier population, I sincerely hope, for the sake of posterity, that they will be content to be stationary, long before necessity compel them to it.According to Mill, the ultimate tendency in an economy is for the rate of profit to decline due to diminishing returns in agriculture and increase in population at a Malthusian rate.What is meant by 'a Malthusian rate' of anything?