The film stars James Stewart as George Bailey, a man who has given up his dreams in order to help others and whose imminent suicide on Christmas Eve brings about the intervention of his guardian angel, Clarence Odbody (Henry Travers). Clarence shows George all the lives he has touched and how different life in his community of Bedford Falls would be had he never been born.
So George, in his despair, contemplates suicide. His repeated failures and disappointments in life lead him to believe that things would have been better had he not been born at all. Clarence intervenes and demonstrates that this is not the case.
The story makes use of what are called "counterfactuals." Counterfactuals are kinds of statements. More specifically, they are types of conditionals. A conditional statement is a statement that commonly takes the form, "If x, then y." Here, x is what call the antecedent. y is called the consequent. Given what has actually happened in the past, a counterfactual starts with the antecedent being some event other than the event that occurred at a particular time in the past. The consequent is an event that would follow the event stated in the antecedent. Here's an example.
Thirty minutes ago there was a sugar cube on my kitchen counter. A counterfactual based on this past event might go, "If that sugar cube had been placed in a cup of hot coffee, it would have dissolved." The counterfactual is stating that if things were different in the past, that would have led to a different state of affairs.
One way to see the movie is as a series of counterfactuals that Clarence states and vividly illustrates. Here are a few.
"If George had not been born, then Bedford Falls would have become Pottersville."
"If George had not been born, then his brother Harry would have drowned."
"If George had not been born, then Mary would have become a lonely spinster."
Are these claims true? How do we assess the truth of these kinds of claims? In metaphysics and philosophy of language, a popular approach is to assess these sorts of claims by employing alternate scenarios. This is what philosophers call "possible worlds." So, a popular approach to evaluating counterfactuals is this: consider the alternate scenarios that are the most similar to our actual scenario, and where the antecedent is true. A counterfactual is true only when in all of these scenarios, the consequent is also true.
Let's use the sugar cube example. Here's the counterfactual again:
"If the sugar cube had been placed in a cup of hot coffee, then it would have dissolved."
First we consider all of the alternate scenarios that are the most similar to our actual scenario, and where the sugar cube is placed in a cup of hot coffee. These alternate scenarios won't be weird ones, where the laws of nature are radically different. That means sugar is made of the same thing, coffee is made of the same stuff, etc. So in all of these alternate scenarios where a sugar cube is placed in a cup of hot coffee, it seems plausible to think that the sugar cube will dissolve. So, we tend to think that this counterfactual is true.
Now, what about Clarence's counterfactuals? Are they true? In order to assess their truth, we consider the alternate scenarios most similar to ours where George has not been born. Given that the world of Bedford Falls would be very similar, excepting the fact that George is not around, can we confidently say that Harry would have drowned, Henry Potter would have taken over, and that Mary would have become a spinster? These subsequent events are so far ahead of the moment of George's non-birth (i.e. the date that he was born) that it is incredibly difficult to say what exactly would have happened. Compare this with the sugar cube example above. That claim is plausible because one event immediately follows another. The more time you place between antecedent and consequent, the more variables you introduce, and the harder it is to say what would follow in such cases. For instance, Henry Potter taking over Bedford Falls would have taken place at least 20-30 years after George's birth date. In that much time in between, there are an insane number of possible scenarios that could occur. Why believe that the scenario where Bedford Falls becomes Pottersville is that one that will play out?
The point is that if George had not been born, any number of things, good or bad, could have happened. Mary could have met another man and have ended up happily married. Harry could have decided not to go out to the frozen pond. Potter could have died in a freak accident. So, it seems clearly obvious that Clarence's point is a false one. What Clarence shows George is just one of many possibilities. There is no reason to think that the possibility Clarence envisages is any more likely to occur than any of the other myriad of possibilities.
This raises an interesting question about what it means for one's life to be meaningful. Many people measure the meaningfulness of life by the impact they have on others. But, how do we measure this impact? Understanding impact in terms of counterfactuals is problematic, as has been shown above. If I weren't around, would people's lives be worse? Maybe, but it seems just as likely that their lives might be better, or that there would be no qualitative change. If having a positive impact on people's lives require that in every similar alternate scenario where an individual doesn't exist, people's lives are qualitatively worse, then no one would have a positive impact on anyone else's lives.
So, two questions from here on out. First, does a meaningful life require that one have some kind of positive impact on others? If so, then how do we measure this impact?