When we were children we used to believe anything was possible, but as we grow older we start to believe more along the lines of 'within reason' which is really another way of saying 'that is beyond me so there isn't even really a point in trying.'
Training, in my life, takes place every day, there is no 'try' about it, it happens, if this frame of mind were to be applied to training would anyone ever really get beyond where they are now? Would they be better than they were yesterday or even the day before that?
Others also like to say the words 'can't' or 'never' or 'impossible' yet fail to realize that with each breath they utter these words, with full conviction, they become reality.
Whatever you put your heart, mind, and spirit into is what you become, what you actualize for yourself in each moment you put yourself into that thing... So 'anything is possible' is the direct gateway to 'within reason' or 'impossible' and there lay the paradox.
Sensei was always fond of pointing these things out without pointing them out, unless he did not actually know he was pointing them out, but just pointing to something deeper each time.
I remember the first board I broke in the Dojo... We were practicing for a demonstration we were going to give at an Elementary School for kids that were right around the same age I was.
The first board did nothing but leave a nasty sting in my hand as I attempted the first hammerfist with as loud a Kiai as I could muster, not knowing a thing about Kiai at the time, it really was nothing more than a loud shout, useless for much else but noise.
Noel Mendoza, my senior at the time, came up to me after I broke the board and was convinced that I had 'scared it' because he swore it 'broke before I even touched it.'
Mind you these were actual boards and not rebreakable boards and it was likely a trick of his eyes because I definitely felt the thing, although it was a different feel than the first time, not as painful.
What was different? The first one I simply TRIED to break the board, I did not break the board, nor did I believe I could break the board, but breaking the board was a possibility, within reason, right? After the first attempt I doubted whether or not it was even possible.
'Think through the board' was sound advice received on the first go, but advice that did not really sink in until I managed to step up for the second go on the same board.
Now it is easy to sit in seiza with a board propped between two bricks, barely lift my flat unclenched hand by maybe an inch and simply drop it through the board, what makes it possible? Anything is possible and the board is already broken.
Is there some sort of mystical thing happening? Is there a metaphysical link between the physical world and my focus? That leads us back to 'within reason' and towards 'impossible' if we try to explain it, apply theories to it, or otherwise quantify it rather than just do it.
Perhaps there are some who need that sort of thing, but it is a double-edged sword, work it into too much theorizing and you end up creating your own limitations, unfortunately said limitations become so hard to break once they are ingrained.
This is the type of focus that should be in each and every motion, each and every breath, each and every second of every single day.