It is not sufficient to observe the fact, it needs to be assessed against its cause.

Frédéric Bastiat
Complete Works, Volume 7, pages 103 to 108 (in French)
Mémorial bordelais, May 19th, 1846

In this article, Frédéric Bastiat delves into the projected railway from Bordeaux to Bayonne. It is possible to spot between the lines one of the issues raised later in the 20th century by the public choice school that will expose the government decision process, which does not necessarily takes profits into account to make economic choices. The question here is to take a decision about the coming route for the railway and Frédéric Bastiat rises up against the reasons that are asserted in favour of one against the other (without judging the decision itself).

What today’s quote is highlighting is that the analysis of a situation cannot be based on a simplistic reasoning. We are not really facing a confusion between correlation and causation (which is a typical mistake that will be exposed in the pamphlet Post Hoc, Ergo Propter Hoc) but he reminds us here that it is not sufficient to observe a fact to conclude on something (a fact allows to validate – or even better, invalidate – a hypothesis but it has no value in itself). In the present case, the undeniable fact of diminishing population, which is being used as a reason for not building a longer railway route, is not sufficient because it has been created by the protectionnist economic policy of government and Frédéric Bastiat hopes indeed that it will be reverted one day. To accept such a fact as ineluctable is to refuse to understand its cause, which, being artificial and unjust, should not be used as an argument.