Just noticed you're having the same discussion I've seen elsewhere so I thought I'd post my comments here too.
A philosophy (aside being an academic/scholastic system of thoughts) is meant (also) as "a way of addressing fundamental questions distinguished by its critical, generally systematic approach and its reliance on reasoned argument".
...or, to call a spade a spade, a way of thinking.
Parkour is the practice of moving past obstacles, to help you get past all obstacles. It is a method, a training system, a practice, a discipline. Doing parkour is training. Using parkour is developing your abilities. It is possible to practise badly (if we don't understand or don't care), but that is different to not practising at all.
To practise you need to move, but you also need obstacles.
If a wall is small then it doesn't limit you and therefore isn't really an obstacle to you (it's not difficult or challenging). To practise parkour you need to find the parts of the environment that are obstacles to you. The parts people use will be as different as the people are different. Fortunately, the environment is varied.
To do anything difficult you need to believe that you can do it. Otherwise you don't even try.
To do anything difficult you need to want to do it. Otherwise you don't even try.
Those thoughts are the philosophy of parkour. I want to get past my obstacles, and I believe that it is possible. That's the way of thinking needed for parkour. You need to think you can get past the obstacles. It is important, it is actually impossible to practise parkour without that, but it's only a tiny fraction of a person's complete way of thinking.
Just for Rafe
, here's an ancient quote, "The philosophy is of always going forwards, never stopping. When I have a problem, when i can't progress, like in life, those problems, there is always a way.
Everyone can do parkour. Parkour exists at the times where there is an obstacle in front of you and you are obliged to use your limbs to pass." ~ David Belle