… It requires a Judge of first instance, before he finds that a particular
event occurred, to be satisfied on the evidence that it is more likely to have
occurred than not. If such a Judge concludes, on a whole series of cogent
grounds, that the occurrence of an event is extremely improbable, a finding by
him that it is nevertheless more likely to have occurred than not, does not
accord with common sense. This is especially so when it is open to the Judge to
say simply that the evidence leaves him in doubt whether the event occurred or
not, and that the party on whom the burden of proving that the event occurred
lies has therefore failed to discharge such burden.”