if I look like a duck, it's a pretty fast one

[keannu]

Did he say "if I look like a duck, it's a pretty fast one" just to contradict he is like a slow duck?

3-8)Our children need faith in themselves and how they see things in order to take action. If they don't trust their own decisions or have confidence in themselves, it's very difficult for them to be self-assertive....Ten-year-old Andrew calls home from camp with a story about one of his cabin mates. "He asked me to be his canoeing partner, but when I got down to the late, he'd buddied up with someone else." Andrew complains. "Then he borrowed my army...And he told me I look like a duck when I run."

Dad is listening intently to his son 150 miles away. He wants to get in the car...Instead, he takes a deep breath and asks his son, "How are you going to handle this?" Andrew answers, "Well, I went canoeing with another guy. And if I look like a duck, it's a pretty fast one, because I came in third in the race." "Way to go," Dad says "And I'm just going to tell him I want my knife back" Andrew continues, "I need it for the hike. If that doesn't work, I'll talk to my counselor"...

Andrew had confidence in his decision that his cabin mate's behavior was unacceptable as well as faith in himself to handle the situation. This seems natural and most people may take it for granted. However, there are children who would choose to ignore the problem because they lack the inner security to tackle it....

[philo2009]

Not at all. This is a non-predictive conditional, in which the protasis denotes an assumption, rather than simply a hypothetical possibility.

It means effectively: "Let us for the moment accept the proposition that I look like a duck. Then the kind of duck that I resemble is a fast one."

[keannu]

What does "security" in the last sentence mean? "Certainty" or "something to reassuran you"?

...they lack the inner security to tackle it...

[5jj]

security, definition #2