Final answer:
The central theme of the story is the importance of relying on one's knowledge and training rather than allowing fear to rule.
Step-by-step explanation:
The central theme of the story 'By Degree and Dilatory Time' is the importance of relying on one's knowledge and training rather than allowing fear to rule. In the story, Mark Twain's character second-guesses himself when faced with challenges, but ultimately learns the lesson that confidence and trust in one's abilities are crucial.