The actual problem is its not possible to assign a percentage probability - or even a vague 'highly likely'- to a once-off event. As long as the prediction is

The actual problem is its not possible to assign a percentage probability - or even a vague 'highly likely'- to a once-off event. As long as the prediction is not 0% or 100%, its impossible to be wrong. So, without hesitation, I predict with 99,999999% certainty that an asteroid will hit the Eiffel tower before the hour.