I'm not sure what separates the possible from the impossible. The line of possibility is infinitely slim, and it moves constantly. It is the line that separates sanity from insanity, joy from sorrow, or life from death.
What is impossible today, may be possible tomorrow. Humans are amazingly adaptable and inventive, and given a task they will push forward through innumerable challenges and suffer great hardships to reach their goal. In the face of a dream, the impossible crumbles like a sand castle before a wave. Or the dreamer crumbles.
This is the only wisdom that I have: each day, one must wake up and accomplish the tasks of that day. Each task may be small, or large, but one must try to push through to a conclusion. Then one can sleep, and dream again.
This seems to me the only way to live. To make each day a microcosm of life, to live it completely and then rest. Any other way, and suddenly life becomes too overwhelming. Dreams become impossible to attain.
I believe that anyone can climb a mountain, one step at a time.