28 Dec 2021

Post hoc ergo propter hoc, or after this, therefore because of this, is a well known logical fallacy. A sequence of events does not guarantee that there is a causal relationship between those that precede and those that follow.  Wise investors know to beware of confusing correlation with causation. A famous and surely harmless example is the Super Bowl indicator that claims that the stock market has a good year when a team from the NFL triumphs but falls if an AFC team is victorious.  Nevertheless, retrospective explanation for the movement of asset prices is a serious industry that seeks to establish an understanding of the past and, by implication, of the future, available only to a select few. I have written about this before. To an investor it doesn’t or shouldn’t matter why an asset rose or fell in price. All that matters is being aligned with the outcome. Occasionally a company that has been performing badly gets taken over at an agreeable price. Shareholders who had invested because they thought that the managers of the business were competent discover that this was not the case but ultimately are rewarded for being wrong. They give thanks and move on, as unelected leaders of their own portfolios, to their next idea without embarrassment. (Or maybe that’s just me). The so-called nonpharmaceutical interventions (NPIs) to deal with Covid-19 have elevated “post hoc ergo propter hoc” from a fallacy to the foundation of policy. Imposing lockdowns, shutting schools and destroying businesses are all actions that I consider cowardly as well as destructive, though it seems that the majority were willing to go along with them as long as the government would drive itself to the edge of insolvency to compensate them. What is, I think, beyond dispute is that the advocates of these NPIs must appear to be supported by convincing evidence that they made a positive difference. Issues of liberty, free speech, mental health and the treacherous Swedes can be relegated to background noise as long as the narrative holds.  Karl Popper proposed the Falsification Principle. It states that for a theory to be considered scientific it must be able to be tested and conceivably...