The problem isn’t in the act of modeling, but that his model has been wrong for the past few centuries.
http://en.wikipedia.org/wiki/Malthusian_catastrophe

Steve, in regards to that same point, what point of Malthus were you specifically referring to? When connecting Malthus and population, I immediately think of the problems of population vs. carrying capacity (i.e. the population that can be supported on a particular area of land up to and including the world as a whole), on which I would suggest that he was not so much wrong as he couldn’t know all the factors that would influence carrying capacity. But I’m not sure that’s what you’re referring to.

Investment bankers, and the entire financial management class were acting in their long term interests in the last few years. As a class, that is. These interests being served by creating the illusion of profit and skimming, risk free, a guaranteed percentage from that illusion. They did not care at all about the firms and stockholders they worked for. Rather they worked in a different time frame (time being another factor that becomes increasingly malleable in production and profit activities after Smith’s era) with different horizons than that of the firms which they were “managing”. When the crash came, they scooted out the back door with their “long term interests” well served and provided for, leaving everyone else holding the proverbial bag.

But anyway, thanks Steve for doing this. It’s quite a treat.

Probably not so much in the era of birth control and border control, but I can imagine what he might have been thinkng of: high prosperity can mean more food production, which means more people, or goods which import more food, ditto, or high wages which attract immigrants.

Nowadays, on a global scale population increase via births doesn’t correspond with prosperity — though it might with prosperity, in some senses, in the history of a region — but economic prosperity sure corresponds well with attractiveness to immigrants.

re: arguments for slavery (in the context of the US) – you are absolutely correct that it was argued that slave owners had to keep slaves in a certain level of comfort. However, it was argued expressly in contrast to the sort of industrial/wage labor that Smith is discussing here. IE, slave apologists contended that, since an industrial laborer could always be easily and cheaply replaced, slaves were actually better cared for. Moreover, since slaves were highly limited in their ability to protest their conditions (not that they would want to), Southern society was more stable than Northern society, where the mistreated laborers could vote. These arguments – that slavery was a better – that is, more humane – way of extracting labor from laborers, and that it also precluded protest by the laborers, were often made concurrently.