I think we need to examine what we mean by ‘fail’.
A plan does not fail simply because the actual outcome is different from the outcome judged most likely; a plan fails when a contingency not prepared for occurs which prevents the intended outcome from being realized, or when an explicit failure state of the plan is reached.
If I plan to go on a vacation and prepare for a major illness by deciding that I will cancel the vacation, then experiencing a major illness might cause the plan to fail- because I have identified that as a failure state. The more important the object of the plan, the harder I will work in the planning stage to minimize the likelihood of ending up in a failure state. (When sending a probe to Mars, for example, I want to be prepared such that everything I can think of that might go wrong along the way still yields a success condition.)
I think we need to examine what we mean by ‘fail’.
A plan does not fail simply because the actual outcome is different from the outcome judged most likely; a plan fails when a contingency not prepared for occurs which prevents the intended outcome from being realized, or when an explicit failure state of the plan is reached.
If I plan to go on a vacation and prepare for a major illness by deciding that I will cancel the vacation, then experiencing a major illness might cause the plan to fail- because I have identified that as a failure state. The more important the object of the plan, the harder I will work in the planning stage to minimize the likelihood of ending up in a failure state. (When sending a probe to Mars, for example, I want to be prepared such that everything I can think of that might go wrong along the way still yields a success condition.)