Recently I was told a story by my Japanese girlfriend about when she was learning English as a kid. She once asked a teacher "Why is 'a' shaped like that?" When they couldn't answer she got fed up and to a certain extent lost interest. When she brought that up I didn't know either. I looked it up later and in doing so I got more fragments but nothing that entirely satisfied my sparked curiousity. I started wondering about things like different fonts, or hand writing styles. The various interpretations of the alphabet in a still recognizable form.
Which, in a way, is like martial arts. There are many different styles and practitioners, but what is it that really distinguishes one style from another, in there being so many different interpretations of the same idea? Also is there really a clear line between separate styles?
This was my response:
When it comes to most things we believe that we have a definitive understanding of what makes anything apply to a specific word or symbol and the word or symbol apply to a specific thing. This is quite misleading. We say that A is A because it is. That's terribly arbitrary! It is giving us the pen of God to write our dictionary because only we will use it.
It is actually quite the opposite which gives us our definitions. In Zen, there is a postulate that says:
A≠A∴A which translates as "A is not A therefore A."
This seems terribly counter intuitive but it should. Logic prevailing, then A which is not can not be at all. This seems as much of a paradox as "This sentence is false." However there is a way, beyond the logic that we can understand this but you've got to do exactly as said.
Look at your hand.
I say, "Your hand is like a bird."
You wait for my explanation or see the bird in your hand.
I say, "Your hand is like my hand," and you notice the 4 fingers, the thumb and the palm.
I say, "Your hand is like your hand," and you realize that this makes no sense.
It can't be like your hand because it is indeed your hand! It would be a stupid sentence and have the feeling of incorrectness.
Think for a moment. What is your hand actually like?
Is it like a fish, a tiger and the universe more than your own hand? No.
Then how is this wrong?
Well, let's simplify.
Your hand is like anything that is not your hand and as such it is your hand.
That can be simplified to "Your hand is like not-your-hand and as such it is not your hand"
We use a simile but we could simply switch it to a metaphor by removing the "like"
Your hand is not-your-hand, therefore it is your hand.
A is not A, therefore A.
Hope that explains how we must step out of our basic definitions and understand our reality beyond the numbers and measures we usually attribute to all of what we call "reliable information."
In an effort to reply to the martial arts aspect of the question, I would like to draw attention to two specific situations. First, a comparison between Aikido and Muay Thai. These styles are so far from each other in most ways that the dividing line is easily seen. Aikido usually involves grabbing an opponent and very few strikes at all. It is about moving with the opponent at the appropriate time to throw them. Muay Thai involves a large amount of striking and with wrapped hands, the grabbing is next to nothing so long as it is understood that a clinch is a body position and not a grab. Thus Muay Thai and Aikido are opposites in many ways and as such they define each other pretty clearly.
Second, a comparison between Karate and Crane Kung Fu. This is where things get hazy. For evidence:
This is a showing of how the concept of the "three-battles" traveled from China to Okinawa and it changed over years of evolution into another but similar practice. There is no real line between the two styles. However we can look at them and say, "That's Crane and that's Karate." This is our own perspectives. Simply understand that as a true and clean witness of your reality, you must be more willing to bend the definitions and as such it will change your perspective on what is truly important in the style you study.
To sum it all up:
Once you know something is, the why or why-not is a matter of perspective and an understanding beyond the self.