Is mankind strong or fragile? What determines this?

Is mankind strong or fragile? What determines this?

In my life, I have experienced times of both extreme strength and hopeless weakness. I have had to deal with a lot of loss in my life and it seems to me that even though when I feel sadness I am typically weak, I tend to grow from that weakness because of it. I like this idea because I am curious about whether people are inherently strong and just suffer weakness from time to time or if it is the reverse. I don't have an answer for this question as of now, so I am excited to explore my life and literature to develop a firm stance.

In The Sun Also Rises by Ernest Hemingway, the majority of the characters seem strong outwardly, but inside they are crumbling. By living lifestyles consisting of partying and feeble attempts at love, they denying their emotions in attempts to be completely happy. Instead, they end up doing more harm to their emotions than good. Since they deny their emotions instead of confronting them, they never learn to deal with them and therefore are unable to get stronger through that success. The people in this novel are fragile. They are unwilling to be strong because they know that would require suffering hardships. Maybe people are only strong if they choose to be. Maybe people are fragile but based on their environment and nurturing they can develop strength that can overcome any weakness, a light in a dark room. Even when the characters rarely face their emotions (usually in a drunken state) they almost always resort back to the way of life they were living previously. At the end of the novel, a woman named Brett tells a man named Jake that they could have had a good life together and Jake says something to the extent of, "isn't it pretty to think so?". Although Brett is acknowledging that she has feelings for Jake that she should have acted on, she will never be with him because he was injured in the war and can no longer have sexual relations. But does this reveal strength or fragilty? In a sense, she is strong because she knows that she shouldn't be with someone that she can't completely commit to, but she is ultimately weak because she cannot rise above the obstacle that has befallen her relationship with Jake. What defines strength? Weakness? How are we able to tell the difference? Strength is trying to overcome obstacles, but weakness is looking at an obstacle and turning back.

In every book that I can remember reading, I see this paradox of strength versus weakness in the characters. For one example, I'm thinking of Holden Caulfield from The Catcher in the Rye by J.D. Salinger. Throughout the book, Holden's character keeps you guessing whether or not he is strong or fragile. He seems to be fairly strong since he can be so independent, but his deep seeded mental struggles prove otherwise. Is he weak because of this? Or is he strong because he is trying to overcome it? Maybe a person is deemed weak when they are unwilling to overcome their weaknesses but they are strong if they make an attempt. And going back to the bigger question, does that mean they are inherently strong or fragile?!? I've definitely got some exploring to do... Another thing I was thinking about is how in history, we often read about the fall of kingdoms at the hand of a "strong" leader. What is the relationship between strength and power? Just because a leader has power clearly doesn't mean he is strong. Or does it take strength to hold a kingdom together? I think it takes strength in unity, strength as one being and strength among individuals. One strong man cannot compensate for a fragile world. Or can he?

I was thinking about a song called Breakable by Ingrid Michaelson. I'll post a link to the lyrics:
http://www.lyricsmania.com/breakable_lyrics_ingrid_michaelson.html
This song really makes me think about mankind in general. We ARE so fragile. We are skin and bones, a couple muscles here and there, and we try to face the terrors in the world despite our vulnerability. This is why I question whether we really are so fragile. Practically every day we hear stories about men surviving freak accidents and putting themselves in life threatening situations simply because it's the right thing to do. Men must be strong. But on the other hand, we hear how many deaths occur in freak accidents and are constantly reminded that we aren't yet advanced enough to fight every disease and probably never will be.

I am officially torn.
More research to come.....