A reply in a conversation with Dan about something else entirely
When I was 19 or so (i.e. anywhere between 17-20 I can't recall) I went on a Ninjitsu (shuddup,it was a recognised martial art) Mind Camp.
We did this exercise over the weekend (or 3 days) where at the start we had to find a stick and carry it with us at all times. We then had to pick a task to achieve. Mine was good marks or something. Then the whole weekend we did these exercises while focussing on the stick where for example, we wondered around and grabbed a random person, and for 40 mins they kept asking us "why" we wanted to achieve that or "how" we were going to do this etc etc. These exercises (loads of different ones but related to achieving this task) were done intermittently with other eastern mind philosophy and martial arts training.
At the end of the weekend we had a big bonfire and all tossed our sticks into it. We were told that our task was achieved. That the burning of the stick illustrated how the task was done, it was gone, it was complete. All we had to go do now was "actually physically go do it" which was considered pretty minor since in REALITY the task was ACTUALLY DONE.
The point I'm trying to make, is that if you have done it in your head, if something is done, the physical merely is a minor actually to get out of the way, because the task is actually done.
Analogy: On the ski slopes, you could jump ridiculous jumps because in your head it was actually done. Actually doing the jump was a minor inconvenience. The same was true for me when I did the jump on the last day (although landing was a major inconvenience because I hadn't done that bit in my head). When I got stuck on the slopes two days earlier, the problem was in my head I couldn't do it. So physically it becomes impossible.
A task is done when you achieve it in your head. Physically performing the action is merely confirms this, and is not the actual achievement itself.