I recently started reading the book "Fooled by Randomness" by Nassim Taleb. So far it is not a book I would recommend to most people (the person who suggested I read it said he usually recommends people start with his most recent book, Antifragile). The author covers very interesting content, but not in a way that is easy to follow or digest. This is the first of probably (hopefully?) a series of posts trying to translate the subject of Taleb's book to an easier to digest format.
While I lived in Ann Arbor during graduate school there was a turn I had to drive about once a month. The unfortunate thing about this turn was that it was a left turn immediately after taking a left at a light. It was so close that I had to make a decision: either move into the middle lane of the road, which was a left turn lane for traffic coming the opposite direction, or remain in the line of traffic, and wait for any oncoming traffic to be clear.
After a few times of taking the turn, I wondered which of the two not-great options I should choose going forward. It seemed to me that I could either risk a low likelihood of a head-on-collision, or a relatively higher likelihood of being rear-ended in the other lane. I settled on staying in my lane and risking being rear-ended because of how much more destructive head-on collisions are.
A few years after making the decision, I made the left turn, and waited for the oncoming traffic to clear as usual. The person who was driving behind me saw the brake lights and stopped. Unfortunately, the person behind them didn't and bumped the middle car into mine. It was fairly minor damage all around, but it is easy to wonder given what happened if I actually made the right choice.
One of the messages from Taleb is that there is complexity in judging the quality of a decision based on random outcomes. For the person who bought a lottery ticket and won, it was a good decision. However, we should advise each person not to buy lottery tickets because in most versions of the universe, the individual you are talking to does not win.
This notion of "most versions of the universe" is a useful one when talking about randomness since it lets you still give weight to things that didn't happen. And while it can be a good idea to update your estimates of probabilities as you get new information, the fundamentals before an event are the same as they are after. As an example, after being rear-ended I did conclude that maybe I should be a bit more aggressive in taking my turn between oncoming traffic. But the fundamentals of my decision didn't change because of it.