There are many "walls" in athletics. Physical and mental challenges that have to be faced and dealt with to accomplish a particular task. 5.12 represents where climbing gets really hard. There is in fact a book How to Climb 5.12 by Eric Horst and it describes how to break through to the next level. I have not read the book but I know several people that have and they say it focuses on training methods to get stronger, both mentally as well as physically. They said the key is: climb a whole lot. I'll get back to that.
So I've been climbing at Movement in Boulder several times this summer on the recommendation of the best climber I know. I saw a guy lead climb a 5.13d a few days ago. That's really hard. In comparison 5.12a is easy. In the past year I've seen a few climbing videos of guys climbing 5.14s and even 5.15s and those are even harder. When I see or hear of someone doing something harder than what I do it makes it easier to do what I do. It is a huge mental breakthrough.
When I look at a particular goal of mine I consider than many people have done harder things and I tell myself that I have the experience to do it. The goal becomes much easier. Breaking a world record or being the first to do something is always harder than being the second or the 1274th person. There is no one to ask for advice. The challenge might not be possible.
I dealt with this concept in my running through high school and college, and I still deal with it. What is fast running? In rock climbing what is hard? As far as mountain altitude, what constitutes high altitude versus moderate altitude? In education what constitutes a difficult concept to learn?
I believe that everyone has something positive to offer. Some gift or some area he or she excels. That is to say for Tommy Caldwell 5.12 is easy. For Chris Solinsky running a five minute mile is not very fast. For many scientists and engineers, physics is not hard, it's fun. Bringing the mentality of "only" a known and conquerable difficulty to a problem makes it possible and even probable that it will be finished well.
As an engineer we were taught to think a certain way. Engineers break up a problem into smaller steps that have to happen in a particular order. Many of my classes involved using several different equations in a certain order to find the answer. Using that mentality climbing a 5.12 becomes only a matter of answering the questions: Where do I put my feet? How do I place my feet (at what angles)? Where do I put my hands? What is the most energy efficient use of my hands? Is my weight on my feet instead of my hands? Am I in balance?
Finally, there is one last component to climbing hard, the physical strength. Can I actually grab a half centimeter thick ledge with three fingers with enough force to keep myself from falling off? Can I keep my feet on that same size ledge? There is a certain amount of strength that is needed to do this kind of climbing. However, having the confidence that you can do it makes a greater difference.
I like throwing new pupils at a task beyond anything they have ever done. Wether that is taking a teenager four pitches up a very steep mountain face for his or her first traditional rock climb, running with a runner farther than he or she has ever run before, or teaching someone how to use a complex computer program. I am thrilled by the expressions on their faces during the event as they wonder if they can do it. I am more thrilled after the event by the way they walk and talk as their confidence goes through the roof. Many people complete a new challenge and think, 'Wow, I just did that!... What else can I do?' I am thrilled when people question the bounds of what is possible. I like answering the question "We can do that?" with the answer "Of course we can!"
The moral of the story is: it's only 5.12, of course you can do it, if that's what you decide to work towards.