Sharpening Occam’s Razor
There is a philosophical concept called “Occam’s Razor.” You can google it to learn all the details, but the concept is this:
When there is more than one explanation for an occurrence, the simplest of the explanations is the most likely.
Put another way, if I come home and find a box of cereal on the floor of the kitchen with the box and bag all torn apart and the cereal gone; it is possible that a wild fox broke into my house and consumed the cereal. Occam’s Razor says it is far more likely my dog went into the pantry, pulled the box from a low shelf and did the damage herself.
While the idea of Occam’s Razor is straightforward, I’ve found a flaw. Not with the concept, but rather with how we humans interpret “simple.” On more than one occasion (three in fact as you will soon see) I have witnessed confusion between the “simplest” explanation with the “most obvious” one. They are not always the same.
Circuit Broken
As many of you know, I ran a handyman business out of my garage for about a year. One day, one of my clients asked me to perform what should have been a very simple job.
In the crawl space under his house he had one of those light fixtures that holds a single bare bulb and is turned on and off by a pull string. This one also had a 3-pronged receptacle on the side.
As is often the case with these fixtures, the pull string had pulled out rendering the light either permanently on or off. I this case it was the latter, making it very hard for him to see in the dark crawl space.
In handyman parlance, is was a direct “replace” job, where I would remove the broken fixture and replace it with an identical part.
Whenever you are working on electrical bits in a house, you must turn off the power to the affected area at the circuit breaker box. Even if you’re working on a ceiling light and you have it turned off at the switch, there may still be current present in the ceiling box, so… always shut off the power at the breaker.
Luckily, the breaker box was only a few feet away from the broken fixture, so I plugged my meter into the receptacle and kept flipping switches until the display went from 120v to 0v. After just a few flips I found the circuit and got to work.
This type of replacement involves only three wires, a white a black and ground (green). All three wires were easily accessible and the old, broken fixture came off with just a few twists of a screwdriver.
The new unit was set up exactly the same way, so within a couple minutes it was in and ready to be tested.
Over the years I have learned the electrical gods do not like cocky electricians, so it is always best to test your work before stuffing everything back into the box.
I flipped the breaker, pulled the string and the bulb came on. Success!
I then went and turned the breaker off again, so as not to be working on live wires as I put it all back together. Once the wires were stuffed back into the box and the screws tightened, I went back to the circuit box to flip the breaker back on for the last time. However, when I flipped it on it popped back off. I tried again and it tripped again.
Ugh, I must have caused a short when I put it all back together.
I went back into the crawl space and took the whole thing apart. Looking at my connections and everything else in the electrical box, I could not see anything out of place. Leaving it all hanging, I went back and tried again… no luck, pop.
Thinking the new part was bad, I removed it completely, leaving the three wires exposed and connected to nothing. Once again… pop.
To me, the simplest cause must have been some mistake I made doing the work. After all, everything was fine before I touched it, right? However, after exhaustive testing, checking and re-checking… it was a bad breaker.
The test I did that worked was the last flip the breaker had in it. $3.79 later, the problem was solved.
Differential Calculus
I drive a 2003 Chevrolet Suburban with 170,000 miles on it. Despite its age and mileage, it is a very reliable vehicle. So reliable in fact, that I often think to myself while driving “Man, I’m really surprised this thing doesn’t break more often.”
A couple weeks ago my daughter took the car to visit her cousin in Georgia for the weekend. Before she left, I gave the car a good “once over” to make sure it wouldn’t give her any trouble along the way. The car was, as expected, just fine. She returned on Sunday afternoon, on time and with no gas in the tank. Teenagers!
An hour later, we headed off to church. I was driving, and as we turned into the parking lot, I did what I have cautioned all my teen drivers not to do… I took the turn a little too wide, hopping the right rear wheel on the curb.
As I was being roundly mocked by everyone in the car, I turned again towards an open parking space and heard an ugly noise.
It sounded like someone was dragging the car sideways across the pavement. I turned again into the open spot and I heard the noise again. Not good. It sounded like the inner rear wheel was binding, and badly.
As I sat in church I began to believe my car was finally broken… and in a bad way. I can fix lots of things on cars, but a new differential? Where would I even get one, how much would it cost, how hard would it be to put in, how many days would I have to ride my bike to work? Suffice it to say, I didn’t get as much out of the mass as I should have. When we got out of church we waked across the street to Chipotle for dinner. I grabbed my phone to do some research before driving the car one foot.
Quick car lesson… a full-size truck like my Suburban has two differentials, one in front and one in the rear. The differential is the part of the car that allows the outer wheel to spin faster when you go around a corner. Big beefy trucks have the ability to “lock” differentials to deal with deep snow, mud, pull friends out of ditches and tree stumps out of the ground. My Suburban has four modes:
- 4-Wheel Auto
- 2-Wheel Drive
- 4-Wheel High
- 4-Wheel Low
Most of the time I keep it in 2-Wheel Drive mode, but the week before it was raining hard one day so I put it in 4-Wheel Auto. I guess I forgot to take it out because when came back to the car after church it was in 4-Wheel Auto mode.
The good news is, my assumption that the 15-year-old car was finally broken… was wrong. What happened was this: When the wheel came off the curb it spun and the car thought I was in the situation where one wheel spins in the mud and the other one does nothing. In an attempt to fix the situation, the car (in Auto mode) locked the rear differential and as soon as I tried to turn, the inner wheel was in fact binding.
I spent the whole hour in church fretting over my broken car. In the end, all I had to do was drive it in a straight line for ? of a mile and… it fixed itself.
Fandango
Another handyman client had me install a new ceiling fan remote control a few months back. This is one of those remotes that controls both the speed of the fan and the light.
I installed the unit and it worked fine.
Last week I returned to this client to do some other work and he informed me that the light was working, but the fan had stopped responding to the remote.
Being human, I assumed something had gone wrong with my installation, or the new unit was somehow defective. I got up on a ladder and reviewed my work. Everything looked fine. I hooked up my meter to the leads going to the fan, hit the remote and the numbers immediately dialed right up to where they should be. There was nothing wrong with the new controller.
Since the fan itself had stopped working, I decided to open it up and have a look inside. Back in the 1990s I worked for an electronics manufacturer and we used to talk about opening up a broken unit and looking for the “untied shoelace.” This would be a disconnected wire or an obviously burned out component. Most of the time you see nothing.
I removed the cap on the underside of the fan, exposing all the wires and there it was… the elusive untied shoelace.
As you can see from the picture below, the capacitor that controls the speed was seriously damaged. I can’t say exactly what caused the gray thing to spooge out the side, but as you can see from the new part, it’s not supposed to be there.
I ordered a new part from Amazon for $7 and three days later the fan was working again.
I recognize in stories one and three, my assumption that I must have messed up, distracted me from the truth of the matter, but any good worker would fall for the same thing. When doing work, most people want to take responsibility rather than looking for something to blame.
The next time you find yourself facing a puzzle of any kind, take a few minutes to look beyond what you think is obvious and maybe, just maybe, you’ll see the simple answer for what it is.