 Weekly Philo of Eco: David Hume's evidential strategy with limited data In the so-called moral (or social) sciences it is sometimes very difficult to measure the facts. In his essay, "The Populousness Of Ancient Nations," (hereafter Populousness) Hume points out that when facts are uncertain, it is appropriate to "intermingle the enquiry concerning the causes with that concerning facts" (000, see also 000). [We wannabe post-Malthusians forget that population-size/growth and political economy were once fully integrated sciences.] Hume admits that this is a second-best-scenario: such intermingling both "ought never to be admitted, where the facts can be ascertained with any tolerable assurance." Hume speaks of the problem of unreliability of data in his discussion "Of Miracles," to make clear how to rule out potentially unreliable testimony about uncertain ‘facts'. But his treatment does little to help one decide between competing data that are in no sense so implausible that, by themselves, they violate a known law of nature. In his political economy, Hume needs, thus, to offer a more subtle, methodological account. One must design theory in such a way that it enables principled constraints on accepting data. Hume is quite explicit that he is dealing with limited reliability of data: "the facts, delivered by ancient authors, are either so uncertain or so imperfect as to afford us nothing positive in the matter ... [And] the very facts, which we must oppose to them, in computing the populousness of modern states, are far from being either certain or complete" (Populousness, 000).