The problem with this scenario, as presented, is that it assumes that "sabotage" is a binary variable. If that were the case, the pool of possibilities would consist of: (1) Fifth Column exists & sabotage occurs, (2) Fifth Column exists & sabotage does not occur, and (3) Fifth Column does not exist & sabotage does not occur (presuming that sabotage, as defined in the scenario, could only be accomplished by Fifth Column). In that case, necessarily, lack of sabotage could only reduce the probability of (1), and therefore could only redu... (read more)
The problem with this scenario, as presented, is that it assumes that "sabotage" is a binary variable. If that were the case, the pool of possibilities would consist of: (1) Fifth Column exists & sabotage occurs, (2) Fifth Column exists & sabotage does not occur, and (3) Fifth Column does not exist & sabotage does not occur (presuming that sabotage, as defined in the scenario, could only be accomplished by Fifth Column). In that case, necessarily, lack of sabotage could only reduce the probability of (1), and therefore could only redu... (read more)