The Sunk Cost Fallacy

Progress Means Taking the Right Road, Whether It’s Less Traveled or Not

On a date with my wife the other day, I ordered fried chicken at a local restaurant. I was in shock when the server brought my order. There before me was half of a fried chicken. I believe the description on the menu said this, but I don’t think I realized just how much food that was. I decided to eat the entire plate of food, anyway. I figure if I’m paying for it, I’m eating it. Three-fourths of the way through, I regretted my decision. But I carried on. Big mistake. After the meal my wife wanted to go for a walk—in the heat. That was not fun.

A Sunk Cost Is a Lost Cost

When someone finishes a course of action because he started it, even if he knows finishing is a mistake, he commits the sunk cost fallacy. Rationally, the cost of the action that’s unrecoverable should not factor in when deciding whether to finish the course.

Consider another example. John is an accountant for a big firm. When he started out, he enjoyed the job. But now he realizes that it’s not for him. Rather, he wants to teach elementary school. What’s keeping him from pursuing a career in education and eventually quitting his job as an accountant? He thinks it would be a shame to change course after he’s put so much time and energy into accounting. John is unwilling to make a change because of an investment he cannot get back.

Counting the True Cost

The sunk cost fallacy can occur in any aspect of our decision-making, even at the level of worldview change. A person who lives most of his life according to a certain worldview—say, atheism or Buddhism—who then becomes convinced the worldview is false might feel reluctant to change because of how much of himself he’s given to it. Even though I believe Christianity is true, this could happen to someone who identifies as a Christian but comes to believe Christianity is false.

I recognize that there are other factors that complicate worldview change and that count as genuine costs. For example, there is the pain of admitting you were wrong, the potential loss of relationships, and the perception of wasted years. And becoming a Christian comes with its own costs, such as giving up everything to follow Christ. Even still, some high-profile people have recently decided Christianity is worth it. In his book and podcast of the same name, The Surprising Rebirth of Belief in God, Justin Brierley catalogues Christians who took this step. He is convinced that there is a turn towards Christianity among elites.

The Better Question

Such a change involves risk. But the important question is not, “What have I already lost?” but rather, “Where do I want to go?” C. S. Lewis writes:

We all want progress. But progress means getting nearer to the place where you want to be. And if you have taken a wrong turning, then to go forward does not get you any nearer. If you are on the wrong road, progress means doing an about-turn and walking back to the right road; and in that case the man who turns back soonest is the most progressive man.… There is nothing progressive about being pig-headed and refusing to admit a mistake.

If one is convinced that the change is right and good, being unwilling to take the step because of irrecoverable costs is irrational.