About the authencity of modern meditation methods

You're absolutely right.

Here, I quote from a Dhamma talk by Ajahn Chah entitled "Unshakeable Peace".

Concerning this issue of samatha and vipassanā, the important thing is to develop these states in our own hearts. Only when we genuinely cultivate them ourselves will we know what they actually are.

He describes samatha and vipassana as states above, and not methods.

Meditation is like a single stick of wood. Insight (vipassanā) is one end of the stick and serenity (samatha) the other. If we pick it up, does only one end come up or do both? When anyone picks up a stick both ends rise together. Which part then is vipassanā, and which is samatha? Where does one end and the other begin? They are both the mind.

He says above that it does not make sense to separate vipassana and samatha.

As the mind becomes peaceful, initially the peace will arise from the serenity of samatha. We focus and unify the mind in states of meditative peace (samādhi). However, if the peace and stillness of samādhi fades away, suffering arises in its place. Why is that? Because the peace afforded by samatha meditation alone is still based on attachment. This attachment can then be a cause of suffering. Serenity is not the end of the path. The Buddha saw from his own experience that such peace of mind was not the ultimate. The causes underlying the process of existence (bhava) had not yet been brought to cessation (nirodha). The conditions for rebirth still existed. His spiritual work had not yet attained perfection. Why? Because there was still suffering. So based on that serenity of samatha he proceeded to contemplate, investigate, and analyze the conditioned nature of reality until he was free of all attachments, even the attachment to serenity. Serenity is still part of the world of conditioned existence and conventional reality. Clinging to this type of peace is clinging to conventional reality, and as long as we cling, we will be mired in existence and rebirth. Delighting in the peace of samatha still leads to further existence and rebirth. Once the mind's restlessness and agitation calms down, one clings to the resultant peace.

See above: The natural way is to start by calming the mind to experience meditative peace (samadhi) arising from the state or quality of serenity (samatha). But then this does not free one from suffering. There is still clinging.

Then the Buddha's investigation proceeded to examining the working of the mind and how it relates to suffering. This then leads to the state or quality of vipassana.

So the Buddha examined the causes and conditions underlying existence and rebirth. As long as he had not yet fully penetrated the matter and understood the truth, he continued to probe deeper and deeper with a peaceful mind, reflecting on how all things, peaceful or not, come into existence. His investigation forged ahead until it was clear to him that everything that comes into existence is like a lump of red-hot iron. The five categories of a being's experience (khandhas) are all a lump of red-hot iron. When a lump of iron is glowing red-hot, is there anywhere it can be touched without getting burnt? Is there anywhere at all that is cool? Try touching it on the top, the sides, or underneath. Is there a single spot that can be found that's cool? Impossible. This searing lump of iron is entirely red-hot. We can't even attach to serenity. If we identify with that peace, assuming that there is someone who is calm and serene, this reinforces the sense that there is an independent self or soul. This sense of self is part of conventional reality. Thinking, "I'm peaceful", "I'm agitated", "I'm good", "I'm bad", "I'm happy", or "I'm unhappy", we are caught in more existence and birth. It's more suffering. If our happiness vanishes, then we're unhappy instead. When our sorrow vanishes, then we're happy again. Caught in this endless cycle, we revolve repeatedly through heaven and hell.

Before his enlightenment, the Buddha recognized this pattern in his own heart. He knew that the conditions for existence and rebirth had not yet ceased. His work was not yet finished. Focusing on life's conditionality, he contemplated in accordance with nature: ''Due to this cause there is birth, due to birth there is death, and all this movement of coming and going.'' So the Buddha took up these themes for contemplation in order to understand the truth about the five khandhas. Everything mental and physical, everything conceived and thought about, without exception, is conditioned. Once he knew this, he taught us to set it down. Once he knew this, he taught to abandon it all. He encouraged others to understand in accordance with this truth. If we don't, we'll suffer. We won't be able to let go of these things. However, once we do see the truth of the matter, we'll recognize how these things delude us. As the Buddha taught, ''The mind has no substance, it's not any thing.''

The mind isn't born belonging to anyone. It doesn't die as anyone's. This mind is free, brilliantly radiant, and unentangled with any problems or issues. The reason problems arise is because the mind is deluded by conditioned things, deluded by this misperception of self. So the Buddha taught to observe this mind. In the beginning what is there? There is truly nothing there. It doesn't arise with conditioned things, and it doesn't die with them. When the mind encounters something good, it doesn't change to become good. When the mind encounters something bad, it doesn't become bad as well. That's how it is when there is clear insight into one's nature. There is understanding that this is essentially a substanceless state of affairs.

The Buddha's insight saw it all as impermanent, unsatisfactory and not-self. He wants us to fully comprehend in the same way. The knowing then knows in accordance with truth. When it knows happiness or sorrow, it remains unmoved. The emotion of happiness is a form of birth. The tendency to become sad is a form of death. When there's death there is birth, and what is born has to die. That which arises and passes away is caught in this unremitting cycle of becoming. Once the meditator's mind comes to this state of understanding, no doubt remains about whether there is further becoming and rebirth. There's no need to ask anyone else.

The Buddha comprehensively investigated conditioned phenomena and so was able to let it all go. The five khandhas were let go of, and the knowing carried on merely as an impartial observer of the process. If he experienced something positive, he didn't become positive along with it. He simply observed and remained aware. If he experienced something negative, he didn't become negative. And why was that? Because his mind had been cut free from such causes and conditions. He'd penetrated the Truth. The conditions leading to rebirth no longer existed. This is the knowing that is certain and reliable. This is a mind that is truly at peace. This is what is not born, doesn't age, doesn't get sick, and doesn't die. This is neither cause nor effect, nor dependent on cause and effect. It is independent of the process of causal conditioning. The causes then cease with no conditioning remaining. This mind is above and beyond birth and death, above and beyond happiness and sorrow, above and beyond both good and evil. What can you say? It's beyond the limitations of language to describe it. All supporting conditions have ceased and any attempt to describe it will merely lead to attachment. The words used then become the theory of the mind.

Theoretical descriptions of the mind and its workings are accurate, but the Buddha realized that this type of knowledge was relatively useless. We understand something intellectually and then believe it, but it's of no real benefit. It doesn't lead to peace of mind. The knowing of the Buddha leads to letting go. It results in abandoning and renunciation. Because it's precisely this mind that leads us to get involved with both what's right and what's wrong. If we're smart we get involved with those things that are right. If we're stupid we get involved with those things that are wrong. Such a mind is the world, and the Blessed One took the things of this world to examine this very world. Having come to know the world as it actually was, he was then known as the ''One who clearly comprehends the world''.

Furthermore, without attainment of serenity, the five hindrances would obstruct any attainment of insight. So below, he teaches to calm the mind first.

Allow the breathing to flow easily at just the right pace, neither too short nor too long. Don't try to make it into anything special. Let the body relax, comfortable and at ease. Then keep doing it. Your mind will ask you, ''How late are we going to meditate tonight? What time are we going to quit?'' It incessantly nags, so you have to bellow out a reprimand, ''Listen buddy, just leave me alone.'' This busybody questioner needs to be regularly subdued, because it's nothing other than defilement coming to annoy you. Don't pay it any mind whatsoever. You have to be tough with it. ''Whether I call it quits early or have a late night, it's none of your damn business! If I want to sit all night, it doesn't make any difference to anyone, so why do you come and stick your nose into my meditation?'' You have to cut the nosy fellow off like that. You can then carry on meditating for as long as you wish, according to what feels right.

As you allow the mind to relax and be at ease, it becomes peaceful. Experiencing this, you'll recognize and appreciate the power of clinging. When you can sit on and on, for a very long time, going past midnight, comfortable and relaxed, you'll know you're getting the hang of meditation. You'll understand how attachment and clinging really do defile the mind.

When some people sit down to meditate they light a stick of incense in front of them and vow, ''I won't get up until this stick of incense has burned down.'' Then they sit. After what seems like an hour they open their eyes and realize only five minutes have gone by. They stare at the incense, disappointed at how exceedingly long the stick still is. They close their eyes again and continue. Soon their eyes are open once more to check that stick of incense. These people don't get anywhere in meditation. Don't do it like that. Just sitting and dreaming about that stick of incense, ''I wonder if it's almost finished burning,'' the meditation gets nowhere. Don't give importance to such things. The mind doesn't have to do anything special.

If we are going to undertake the task of developing the mind in meditation, don't let the defilement of craving know the ground rules or the goal. ''How will you meditate, Venerable?'', it inquires. ''How much will you do? How late are you thinking of going?'' Craving keeps pestering until we submit to an agreement. Once we declare we're going to sit until midnight, it immediately begins to hassle us. Before even an hour has passed we're feeling so restless and impatient that we can't continue. Then more hindrances attack as we berate ourselves, ''Hopeless! What, is sitting going to kill you? You said you were going to make your mind unshakeable in samādhi, but it's still unreliable and all over the place. You made a vow and you didn't keep it.'' Thoughts of self-depreciation and dejection assail our minds, and we sink into self-hatred. There's no one else to blame or get angry at, and that makes it all the worse. Once we make a vow we have to keep it. We either fulfill it or die in the process. If we do vow to sit for a certain length of time, then we shouldn't break that vow and stop. In the meantime however, just gradually practise and develop. There's no need for making dramatic vows. Try to steadily and persistently train the mind. Occasionally, the meditation will be peaceful, and all the aches and discomfort in the body will vanish. The pain in the ankles and knees will cease by itself.