Fate has already established someone's future, even if their minds decide to change it. All those small changes that they may have brought with their decisions are already dictated by Fate.
Ezra Pound personifies Fate by using a capital letter, indicating it is a divine stronger force who is out of man's grasp. However, even if Fate, or God, has already decided and written someone's future, a person can forget about living at its expense, and follow what his/her heart and soul demands.
