Sunk costs in Kabul

The "sunk cost fallacy" is an important concept in business investment. Here's a definition from The Skeptic's Dictionary:

When one makes a hopeless investment, one sometimes reasons: I can’t stop now, otherwise what I’ve invested so far will be lost. This is true, of course, but irrelevant to whether one should continue to invest in the project. Everything one has invested is lost regardless. If there is no hope for success in the future from the investment, then the fact that one has already lost a bundle should lead one to the conclusion that the rational thing to do is to withdraw from the project.

It's a concept that has applications outside the business world. The UK's new Defence Secretary is guilty of a sunk cost fallacy in his approach to the Afghanistan conflict. According to The Guardian, Fox says Britain would be betraying the sacrifices of its fallen soldiers if it left "before the job is finished".

There are plenty of precedents. Let's go back to The Skeptic's Dictionary:

To continue to invest in a hopeless project is irrational. Such behavior may be a pathetic attempt to delay having to face the consequences of one's poor judgment. The irrationality is a way to save face, to appear to be knowledgeable, when in fact one is acting like an idiot. For example, it is now known that Lyndon Johnson kept committing thousands and thousands of U.S. soldiers to Vietnam after he had determined that the cause was hopeless and that the U.S. would not win the war (McMaster 1998: 309).

Read it and weep, Liam. "Pathetic attempt"? "Acting like an idiot"? Not the kind of feedback you want, is it, but it's what you'll get if you persist in sacrificing the future in a doomed attempt to expiate the errors of the past.