When someone says you are being illogical, that generally is not a compliment. Acting, speaking, and writing logically are essential to having order in and structure to our lives. If we repeatedly cannot discern the logic of words and deeds, our lives take on the appearance of irrational chaos.
There is, however, a widely recognized exception to these general propositions: humor. In particular, many jokes are funny because they violate one or more logical canons. In Chapters 7 and 9 of Reading, we saw how some jokes turn on the fallacy of equivocation (ambiguity). Here, we will focus on how some jokes employ necessary and/or sufficient conditions to work. Necessary and sufficient conditions often present the most difficulty to students first encountering the study of logic. Looking at their operation in jokes helps to make these concepts clearer.
There is a genre of jokes which we may loosely refer to as “Conversations with God” jokes. Typically, they work because the main character makes a logical mistake as to what is a sufficient or necessary condition for some desired outcome. He finds out his mistake when he finally has a conversation with God. Here are three jokes in this genre, all variations on the same structure, but with some logical twists.
Joke #1.
One night a man gets down on his knees and says this prayer: “Dear God, I try to be a good person. I’m as generous as my conditions allows. I pray and go to church regularly. You know I am poor. Please, please, please let me win the lottery.”
The next day the lottery numbers are drawn and he doesn’t win. So he repeats his prayer that night.
He doesn’t win the lottery the next day, so he repeats his prayer again that night. And on and on for many months.
Finally, one night in the middle of his prayer, there is rumbling in the skies, a bright light shines down upon him, and he hears this loud, booming voice: “Hey, buddy, do me a favor. Buy a ticket.”
In the punch line, God effectively points out to the man that he is making a logical mistake. The man (apparently) believes that being a good person, being generous, praying, and going to church regularly are as a group (jointly) a sufficient condition for him to win the lottery, even if he does not buy a ticket. God’s reply tells him that this is not the case. God’s reply in effect tells the man that buying a ticket is a necessary condition of winning the lottery (God can’t make the man a winner if he doesn’t buy a ticket). God is also telling the man that buying a ticket may be either a sufficient condition or part of a set of jointly sufficient conditions for the man to win (i.e., buy a ticket and you may win, but God doesn’t guarantee that outcome in his reply).
Joke #2
One year, the flooding got particularly bad in the town of Floodville. As the waters rose one early morning, the local minister was standing in his first floor living room up to his ankles in water. The police knocked on his door and asked him to get in the rescue boat waiting outside. He refused, saying, “No thanks. I’ve led a holy life. I’m sure God will save me.”
As the waters continued to rise, the fire department found him that afternoon in waist-deep water on the second floor of his house. Once again, he refused to get in the rescue boat the department had brought. He said again, “No thanks. I’ve led a holy life. I’m sure God will save me.”
Finally, the next day he climbed to the top of his roof to get above the raging waters. The National Guard came by with a third rescue boat and again the minister refused to get in. He told the Guard, “No thanks. I’ve led a holy life. I’m sure God will save me.”
The flood waters kept rising, swept him away, and he drowned. When he got to heaven, he asked God, “Why didn’t you save me from the flood? I was sure you would save me. You know that I lived a holy life, followed your commandments, helped the poor, and was kind.” To which God replied, “Hey, Reverend, I sent you three rescue boats.”
God’s reply in effect tells the minister that (a) the minister was mistaken in believing that living a holy life, following the commandments, helping the poor, and being kind were sufficient conditions, jointly or separately, of being saved from the flood, and (b) getting into one of the rescue boats was a necessary condition (and presumably also a sufficient condition) of being saved. God’s reply is ambiguous as to whether the minister’s living a holy life, following the commandments, helping the poor, and being kind were a necessary condition for him (God) to have sent the three rescue boats to the minister; we don’t know from the joke whether God sent rescue boats to saints and sinners alike.
Joke #3.
When the Covid pandemic began in 2020, a very devout, religious man prayed every night, “Dear God, I go to church every week, I pray to you every day, and I do good works for the poor. Please don’t let me die from Covid.”
After the Pfizer vaccine was made available, the man’s friends urged him to get vaccinated, but he always told them, “No need. I pray to God every night; I’m religious and go to church every Sunday. I do good works for the poor. God will protect me from dying from Covid.” So he continued his same prayer every night, “Dear God, I go to church every week, I pray to you every day, and I do good works for the poor. Please don’t let me die from Covid.”
When the Moderna vaccine was made available, his friends urged him to get vaccinated, but he always told them the same thing: “No need. I pray to God every night; I’m religious and go to church every Sunday…. God will protect me from dying from Covid.” So he continued his same prayer every night, “Dear God, …” and so on.
When the Johnson & Johnson vaccine was made available, his friends urged him to get vaccinated, but he always told them, “No need. I pray to God every night; I’m religious and go to church every Sunday. God will protect me from dying from Covid.” So he continued his prayer every night, “Dear God, …”
Well, as things played out, the man did not get vaccinated, got Covid, and died. When he got to heaven, he went to God’s throne and asked him, “God, I went to church every week, I prayed to you every day, I did good works for the poor. I thought you were going to protect me. Why didn’t you save me from Covid?”
God replied, “I did. I sent you three vaccines.”
The analysis is largely the same as with Joke #2. Note this twist, however, which arises because Joke #2 does not depend on the minister praying to God, whereas the man’s prayers to God (to save him from Covid) are essential to Joke #3. In the punchline in Joke #3, God is effectively telling the man that recognizing when he (God) answers your prayers (the three vaccines) is a necessary condition of that answer having the effect prayed for (saving the man’s life). In other words, a vaccine plus the man’s recognizing that the vaccine was how his prayers were answered are jointly necessary conditions for his being saved from death by Covid. Further, note that the availability of the vaccine by itself was not a sufficient condition of being the man’s saved (of his prayers being answered), but that the availability, plus recognizing that taking the vaccine would prevent his death, plus actually taking the vaccine were jointly sufficient conditions of not dying from Covid (the answer to the man’s prayers).
Sometimes analyzing a joke kills its humor; analyze it and it’s no longer funny. But just as often, analyzing a joke and seeing a violation of a logical rule gives it greater meaning. You gain a deeper appreciation of how and why it is funny. There are many other jokes that turn on errors in recognizing necessary and sufficient conditions. The internet is full of them. Check it out.
Reading Argumentative Texts 