The problem with imagining Oswald not killing Kennedy is that we have to figure why he didn’t do so. He did it for a reason. Was that reason absent? Was Oswald different in some way?
There is a chain of events before the one that we imagine changed, just as there is a chain of events after. And when we snip out that one event, it would have implications backwards in time as well as forwards. I guess this is where this Pearl model is supposed to tell us how to think about snipping out that event, with minimal backwards-in-time changes—but I can’t help wondering if that isn’t an arbitrary measure. Why not snip out the event with minimal forwards-in-time changes? Or why not minimize the sum of forwards and backwards changes? That last metric would surely lead to Kennedy being killed in much the same way by another person, since Kennedy living would likely have led to enormous future changes.
In more detail, suppose there was in fact no conspiracy and Oswald was a lone, self-motivated individual. It might still turn out that the simplest way to imagine what would have happened if Oswald had not killed Kennedy, would be to imagine that there was in fact a conspiracy, and they found someone else, who did the job in the same way. That would arguably be the change which would minimize total forward and backward alterations to the timeline.
The problem with imagining Oswald not killing Kennedy is that we have to figure why he didn’t do so. He did it for a reason. Was that reason absent? Was Oswald different in some way?
There is a chain of events before the one that we imagine changed, just as there is a chain of events after. And when we snip out that one event, it would have implications backwards in time as well as forwards. I guess this is where this Pearl model is supposed to tell us how to think about snipping out that event, with minimal backwards-in-time changes—but I can’t help wondering if that isn’t an arbitrary measure. Why not snip out the event with minimal forwards-in-time changes? Or why not minimize the sum of forwards and backwards changes? That last metric would surely lead to Kennedy being killed in much the same way by another person, since Kennedy living would likely have led to enormous future changes.
In more detail, suppose there was in fact no conspiracy and Oswald was a lone, self-motivated individual. It might still turn out that the simplest way to imagine what would have happened if Oswald had not killed Kennedy, would be to imagine that there was in fact a conspiracy, and they found someone else, who did the job in the same way. That would arguably be the change which would minimize total forward and backward alterations to the timeline.