DISCLAIMER: The purpose of this post is to clarify why the Goenka meditation tradition scan the body. The purpose is NOT to undermine other techniques or schools of thought.
Came a cross some posts where people have asked why the body is scanned in the Goenka tradition. I hope the following satisfies the curiosity of people who do not follow this tradition.
In the Goenka technique, bodily sensations (vedana) play a major role in the psychological programming of human beings. Every action, mental state has a corresponding sensation (vedana). For good or worse, these psychological habit patterns, colour an individuals personality and interactions with itself, others and its environment. How?
Here is analogy with a flicker book ( analogies are a risky affair, take it with a pinch of salt ). Imagine the steps below in the 'Chain of Conditioned Arising ' ( Paticca Samuppada Sutta, Sumyutta Nikaya XII ) as an INFINITE flicker book:-
a) Each page represents a step on the flicker book ( see 'Chain of Conditioned Arising' below ).
b) The text on each page represents all the pertinent details related to that specific step.
c). The pages can only transition sequentially to the next page if the previous page exists. Otherwise, the next page begins at step 1.
Now imagine this flicker book simulates you and that each grouping of steps 1 - 10 represents a single instance of you (mind and body phenomena ) for an imperceptibly small fraction of a second. Because of your psychologically conditioned state (due to ignorance ), these steps keep repeating. The flicker book (you), keeps flickering. On each instance your falling in and out of existence (the death of your mind-body phenomena ). So basically, your a flickering stream of birth - death, birth - death, birth - death, birth - death, birth - death, etc. These transitions happen at such an imperceptibly rapid speed that they give you the false impression that you are a solid constant entity with a permanent self.
What is a vedana (sensation)?
With regards to this technique, a vedana, is any tactile physiological or biochemical reaction that you are able to feel. If you can physically feel it, it's a sensation. There is a whole spectrum of sensations from the gross (easily felt) to extremely subtle ones (that need further training and progress to feel ). Whenever you interact with any external sensory object (a vision, a sound, a smell, a taste or tactile thing), whether its an inanimate or living thing (another person / animal ), you generate a corresponding vedana (sensation). Note here, you're never directly interacting with the external object itself, only to the sensory datum that you receive from your senses or mind (thoughts, imagination, emotions). You don't like the look of a particular person. It's not the person that you hate but the sensation that this visual representation of this person that you recognise and so on for all the other various situations you come across. An alcoholic is not addicted to alcohol but to the sensations that results from consuming the alcohol. You dislike a particular trail of thought that has arisen. Its the actual sensations that correspond to these thoughts that you dislike, that you are reacting to.
Chain of Conditioned Arising
Forward Order:
1. With the base of ignorance, reaction arises;
2. with the base of reaction, consciousness arises;
3. with the base of consciousness, mind and body arise;
4. with the base of mind and body, the six senses arise;
5. with the base of the six senses, contact arises;
6. with the base of contact, sensation arises;
7. with the base of sensation, craving and aversion arise;
8. with the base of craving and aversion,attachment arises;
9. with the base of attachment, the processoff becoming arises;
10. with the base of the process of becoming, birth arises;
11. with the base of birth, ageing and death arise, together with sorrow,
lamentation, physical and mental sufferingsandd tribulations.
Thus arises this entire mass of suffering
The important question is how do you break this cycle? At what point in the cycle is it most effective?
Look at steps 7 to 9: ( 7 ) with the base of sensation, craving and aversion arise, ( 8 ) with the base of craving and aversion, attachment arises; ( 9 ) with the base of attachment, the process of becoming arises.
If you can train yourself to observe these sensations without reacting to them you break the chain for that particular group of conditioned states (back to analogy: those pages that proceed step 7. Imagine you rip out pages corresponding to steps 7 to 10). Then the process continues with another psychological habit pattern that gives rise to another set of conditioned steps 1 to 10 ( generating new pages in the flicker book analogy). You have stored up trillions upon trillions of these conditioned states that will keep multiplying every time you react to their corresponding sensation. Remember, as well as having a huge storage of these conditioned states you are also creating new ones every time you react to their corresponding sensation.
You cannot choose which sensations arise. When they arise and where on the body they arise. This is why you have to scan the entire body. If you don't scan the entire body, you will fail to observe that particular sensation and allow it to multiply and add to the existing store of psychological habits / reactions, etc.
This is not to be blindly accepted but to be experienced. It must be result orientated. If through your daily meditation and daily life you've noticed the benefits of observing your sensations then the results speak for themselves. No ones perfect. You'll make many mistakes. Persistence is the key. Gradually, you'll notice small steps to an improved life (your more chilled and happier until you react to something inappropriately ).
Also, Anapana ( breath observation) and metta bhavana (loving kindness meditation) have a huge influence on your ability to handle difficult situations (with it's corresponding sensation).
There's a lot more to say but I'll leave it here (e.g. emotions also have corresponding tactile sensations that indirectly allow you to observe emotional states / mental dispositions ).