When people are learning how to read and write modern languages using Roman Alphabet, one begins with recognizing and pronouncing the letters of A, B, C, and so on. And then one learns about the utilization of the vowels a, e, i, o, u, and some combinations of different vowels, and so on. Then one will be learning how to pronounce and recognize simple words made out of the combination of letters and vowels. Then, one will advance further by pronouncing and recognizing more complicated and challenging words as well as learning about grammars and tenses while making sentences with combination of words utilizing appropriate grammars and tenses, and so on.
People would think and believe that basic or beginner yoga practice means learning and doing some simple and basic physical yoga poses or exercises (Asana), observing some code of conducts of do's and don't do's (Yama and Niyama), as well as doing some basic cleansing and breathing exercises (Kriya and Pranayama) to purify, balance and charge the energy centres and channels, to purify the mind on the gross level as well as rendering the mind calm and quiet, preparing the mind for the practice of withdrawal of the senses, concentration and meditation (Pratyahara, Dharana and Dhyana) that would purify the mind on subtler level.
As the body developed certain degrees of physical strength, flexibility and skill, the yoga practitioners will advance in their yoga asana practice by doing some more complicated and challenging physical yoga poses or exercises that require certain degrees of physical strength, flexibility and skill, as well as doing some advance cleansing and breathing exercises.
While many yoga enthusiasts would think and believe that 'practicing yoga' means doing some form of basic, intermediate and advance yoga poses and exercises, cleansing and breathing exercises, step by step, level by level, as the basic yoga practice that needs to be done for many years before one shall be introduced with the teachings of yoga about the modification of the mind and mind conquest about the annihilation of the mind, after the mind is rendered calm, pure and quiet.
There's nothing wrong with that understanding and procedure.
However, somehow, even after years and years of performing all kinds of 'basic/intermediate/advance' yoga practice regularly, and the body and mind has been gaining some physical and mental benefits as part of the side-effects of performing those yoga practice regularly, but the mind might still be functioning under the influence of ignorance and egoism, where it still has intense attachment and identification towards a personal and group identity that built on a particular worldly passionate social, cultural, spiritual, religious, regional, national or political thinking, belief, values, practice, actions and the fruit of actions, and hence, it's not free from the restlessness and suffering deriving from ignorance and egoism.
This is due to the practitioner is performing all kinds of physical and mental yoga exercises regularly getting all kinds of benefits, but without the basic foundation of dispassion, renunciation, desirelessness of non-craving and non-aversion, non-attachment and non-identification, to stop generating 'rubbish' from within the mind itself.
Maybe many yoga enthusiasts might not be aware of, actually in the traditional lineage of yoga, the new students are just living closely to the teacher and doing some daily chores for many years (some are up to 12 years), which is about developing the basic foundation of dispassion, renunciation, desirelessness of non-craving and non-aversion, non-attachment and non-identification, in order to be equipped with the 'mental fitness' before the students are being introduced to the yoga practice of Yama, Niyama, Asana, Pranayama, Kriya, Pratyahara, Dharana, Dhyana, Samadhi, and so on.
This 'mental fitness' or 'prerequisite' before the start of many different types of yoga practice is like the foundation of a house. If the foundation is not good enough, or is completely absent, then there will be many 'problems' with the house, risking those who live in the house and those who are in the surrounding environment as well, no matter how much effort and money has been spent onto decorating the inside and outside of the house with many precious and beautiful things.
This foundation in yoga, is about eliminating egoism and all kinds of worldly passionate egoistic influences in the mind. It's about performing actions and renouncing the fruit of actions.
The practice of dispassion and renunciation (disinterest towards worldly passionate objects and affairs, and moving away from worldly relationships, connections, interactions and activities), the practice of desirelessness of non-craving and non-aversion, and the practice of non-attachment and non-identification towards the qualities of names and forms, particularly towards the selfless impermanent physical body and modification of the mind, which will lead towards detachment and dis-identification towards all the existing 'worldly identities with qualities of names and forms' based on particular thinking, belief, values, practice, actions and the fruit of actions, is indeed the basic yoga practice that would be efficiently reducing or cutting off 'worldly passionate egoistic influences or inputs' in the mind, that would allow the mind to perceive everything as it is, and see things as they are, without being contaminated by any worldly thinking, belief, values and practice deriving from ignorance and egoism to analyze and judge everything, to act and react.
This well-trained mind stops generating 'rubbish' from within the mind. It stops hurting itself and/or others.
There's nothing wrong when the mind is practicing dispassion, renunciation, desirelessness, non-attachment and non-identification, but due to certain reasons and limitations, this mind might not be doing any particular form of yoga practice under particular names and forms.
It would be good also, if the mind is practicing many different types of yoga practice along with the foundation practice of dispassion, renunciation, desirelessness, non-attachment and non-identification.
Meanwhile, just by doing many different types of yoga practice under many different names and forms, but without the practice of dispassion, renunciation, desirelessness, non-attachment and non-identification, it could be something else, and most probably, the mind is still swaying between satisfaction and dissatisfaction, happiness and unhappiness, meaningfulness and meaninglessness, joyfulness and painful sorrow, and so on, due to the momentary side-effects of performing the different types of yoga practice. Such as, after a yoga and/or meditation session, the mind says, "Wow! I feel so good." And then, if due to some reasons, there are certain days void of yoga and/or meditation practice, the mind says, "Mmm... I don't feel good."
Just like the knowledge and action of using the letters and vowels to create words and sentences, and expressing many ideas through writing while learning about many things through reading, is neither good nor bad. However, depending on the reasoning power to reason everything that we read, as well as depending on the intention of creating certain words and sentences, we can turn the knowledge and action of reading and writing into something beneficial or harmful. Just like a lawyer or a doctor can be utilizing their particular knowledge, skill and opportunity to be doing something beneficial or harmful to oneself and/or others depending on their reasoning power and intention.
What is determining the reasoning power and intention that influencing whether the minds utilize the knowledge, skill and opportunity to be doing something beneficial or harmful for oneself and/or others, is similar to the presence and absence of the basic foundation of dispassion, renunciation, desirelessness, non-attachment and non-identification that is influencing whether the minds utilize the knowledge, skill and opportunity in yoga to be doing something beneficial or harmful for oneself and/or others. There have been quite some corruptions existing in the world of yoga, even among those who have been practicing and teaching yoga for many years, this is due to these minds were/are functioning under the influence of ignorance and egoism. It's not the fault of the teachings or practices.
Some corrupted minds might even use the teachings of selflessness, oneness, non-separateness, non-duality of neither right nor wrong/neither good nor bad, as well as the practice of performing selfless community service of serve, love and give, desirelessness, non-attachment and non-identification to justify their own impure egoistic lustful misconducts of taking advantage, exploiting and hurting other people for satisfying their own lustful desires. Again, there is nothing wrong with the teachings and practice of yoga, but it's coming from these corrupted minds themselves, generating such misconducts out of their own ignorance, egoism and impurities. Even the 'victims' of these corrupted minds, themselves are not free from the influence of ignorance and egoism, because the corrupted minds wouldn't have any opportunity to be taking advantage, exploiting or hurting the minds that are free from ignorance and egoism.
Inquire the truth of everything.