Prior to contemplating "Population," Darwin believed that populations grew until they were aligned with existing resources, and then stabilized.
Thomas Malthus' work helped inspire Darwin to refine natural selection by stating a reason for meaningful competition between members of the same species.
They are the precursors in the great army of destruction, and often finish the dreadful work themselves.
But should they fail in this war of extermination, sickly seasons, epidemics, pestilence, and plague advance in terrific array, and sweep off their thousands and tens of thousands.
We'd rediscovered science and reason and in the 1700s, we saw that come about with even more progress of society.
As we exit the 1700s and enter into the 1800s, we start having the Industrial Revolution.Darwin had many other sources from which he developed his theory.Yet, if evolution was the machine, and natural selection was the engine, then Malthus' perpetual struggle for resources was the fuel.Should success still be incomplete, gigantic, inevitable famine stalks in the rear, and with one mighty blow levels the population with the food of the world." So not so uplifting of a little quote right over here. He lived in a time where people were being very optimistic that progress, the march of progress, would go on forever until we got to some utopian civilization.But from Thomas Malthus' point of view, he felt that if people could reproduce and increase the population, they will, that there's no way of stopping them.Darwin considered that some of the competitors in Malthus' perpetual struggle would be better equipped to survive.Those that were less able would die out, leaving only those with the more desirable traits.So from his point of view, the way he saw it-- so let me on that axis-- let's say that that is the population, and that this axis right over here, let's say that that is time.So by his thinking-- and everything that he'd seen in reality up to that point would back this up-- that if people had enough food and time, they would reproduce, and they would reproduce in numbers that would grow the population.And people saw the steady march of human reason, of human progress.And because of this, a lot of people were saying, hey, humanity will continue to improve.