How do we know attaining complete liberation from dukkha is possible?

By reaching stream-enter, all doubts vanish for him (not us/we!), good householder, after one has really left home, at least for some while.

And let Atma ask: what is this the ongoing brain-masturbating (stimulating useless, just for 'joy', actually not having a current relation) good for? Investigating the reason might give a lot of answers for release directly.

Ehipassiko!

And Faith In Awakening might be of help for those serious about it, facing the first Noble truth, not just bored playing around after some "sex".

...The Buddha never placed unconditional demands on anyone's faith. And for anyone from a culture where the dominant religions do place such demands on one's faith [science for example], this is one of Buddhism's most attractive features. We read his famous instructions to the Kalamas, in which he advises testing things for oneself, and we see it as an invitation to believe, or not, whatever we like. Some people go so far as to say that faith has no place in the Buddhist tradition, that the proper Buddhist attitude is one of skepticism.

But even though the Buddha recommends tolerance and a healthy skepticism toward matters of faith, he also makes a conditional request about faith: If you sincerely want to put an end to suffering — that's the condition — you should take certain things on faith, as working hypotheses, and then test them through following his path of practice....

Faith, Saddha, has Dukkha as it's cause, and Awakening goes back to Saddha. One not seeing the suffering in stimulating, how could Saddha and letting go of unskilfull, the path, ever arise? He wouldn't let go, even if actually knowing and only suffering would an informed lead out.

And no, like some stated here, it's not required to reach Paranibbana, or Arahatshipp first to be sure that complete ending of suffering is possible. What one drives further after having seen for oneself the first time by enter the stream, is knowing and one is actually already pound, just a matter of time and effort, the fire still burning and hurting lesser or stronger behind. Not easy to abound the fetter of doubt for the most, blind on one or both eyes, since it needs both, perceiving suffering and the way out.

[Note that this isn't given for stacks, exchange, households our other world-bindind trades, but for release]

You know it because you know there is Dukkha. Also you know there is remedy. Question springs from the Answer you already had.

Remedy is painful, like a bullet shot in body persist a wound. A remedy to pull out the bullet is painful process. So, one let physician do nothing. He says, let bullet be there. It's a painful to pull out.

It's the same case here. You know by ending of sorrow, 'you' comes to end. 'You' finish, you die. Who want to come to an end? Only those who accept Pain. Hope, this answers what you looking for.

For most individuals, liberation is not possible. Why dwell on what is not possible? Let it go.

174. Blind is the world; here only a few possess insight. Only a few, like birds escaping from the net, go to realms of bliss.

175. Upon a heap of rubbish in the road-side ditch blooms a lotus, fragrant and pleasing.

176. Even so, on the rubbish heap of blinded mortals the disciple of the Supremely Enlightened One shines resplendent in wisdom.

Dhammapada

I surveyed the world with the eye of an Awakened One. As I did so, I saw beings with little dust in their eyes and those with much, those with keen faculties and those with dull, those with good attributes and those with bad, those easy to teach and those hard, some of them seeing disgrace & danger in the other world.

MN 26

Below, Ven. Ananda answers your question in SN 51.15, but I'm not sure if that's what you're looking for. He answers the question of whether the path to end desire using desire, is a finite one or an endless one.

If you ask, is it possible to know that one has attained Arahatship, I would say yes, because all mental suffering, unsatisfactoriness and discontent would cease without remainder. Even the slightest mental discontent would reveal the fact that one is not an Arahat.

If you ask, is it at all possible to attain complete liberation from suffering, I would say this. The theoretical background of Buddhism is sound and complete, and this is partially explained in Andrei's answer. Has somebody attained enlightenment based on this? Yes. The Buddha and his direct disciples did.

But can you know for sure that it's possible to attain complete liberation from suffering without faith and/or direct experience of it? I would say, "NO". After all, many ascetics in the Buddha's time wandered aimlessly without finding liberation. Worse still, some of them experienced temporary jhana states and may have mistaken it for complete enlightenment.

Is it important to know that complete liberation from suffering is possible? I would say "NO". Even a lay person practising the Five Precepts, Right Action, Right Speech and Right Livelihood, should already experience a significant reduction in suffering, compared to one who does not practise these. The benefits even for a beginner are self-evident to justify the whole path.

From SN 51.15:

“This being the case, Master Ānanda, the path is endless, not finite. For it’s not possible to give up desire by means of desire.”

“Well then, brahmin, I’ll ask you about this in return, and you can answer as you like. What do you think, brahmin? Have you ever had a desire to walk to the park, but when you arrived at the park, the corresponding desire faded away?”

“Yes, sir.”

“Have you ever had the energy to walk to the park, but when you arrived at the park, the corresponding energy faded away?”

“Yes, sir.”

“Have you ever had the idea to walk to the park, but when you arrived at the park, the corresponding idea faded away?”

“Yes, sir.”

“Have you ever inquired regarding a walk to the park, but when you arrived at the park, the corresponding inquiry faded away?”

“Yes, sir.”

“In the same way, take a mendicant who is perfected—with defilements ended, who has completed the spiritual journey, done what had to be done, laid down the burden, achieved their own true goal, utterly ended the fetters of rebirth, and is rightly freed through enlightenment. They formerly had the desire to attain perfection, but when they attained perfection the corresponding desire faded away. They formerly had the energy to attain perfection, but when they attained perfection the corresponding energy faded away. They formerly had the idea to attain perfection, but when they attained perfection the corresponding idea faded away. They formerly inquired regarding attaining perfection, but when they attained perfection the corresponding inquiry faded away. What do you think, brahmin? This being the case, is the path endless or finite?”

“Clearly, Master Ānanda, this being the case, the path is finite, not endless. Excellent, Master Ānanda! Excellent!

Nirvana (lit. "blowing out"), Satori (悟り, "awakening") or Kenshō (見性, "seeing the true nature") does not equate "the eradication of dukkha". It is seeing the true nature of the arising duality of concepts like dukkha and sukkha.

In some aspects, this is very much like the scientific method: science created theories that predicted the existence of atoms, quarks & gluons making out these atoms long before we developed technologies to detect them. Our human sensory range is ill-equipped to "see" this level of reality, but experiments have demonstrated it exists. These theories and experiments undergo peer review before they are accepted or rejected, and any scientist is free to criticize any hypothesis or theory. This principle is similar to these words in the Kalama Sutra:

• Do not believe anything on mere hearsay.
• Do not believe in traditions merely because they are old and have been handed down for many generations and in many places.
• Do not believe anything on account of rumors or because people talk a a great deal about it.
• Do not believe anything because you are shown the written testimony of some ancient sage.
• Do not believe in what you have fancied, thinking that, because it is extraordinary, it must have been inspired by a god or other wonderful being.
• Do not believe anything merely because presumption is in its favor, or because the custom of many years inclines you to take it as true.
• Do not believe anything merely on the authority of your teachers and priests.
• But, whatever, after thorough investigation and reflection, you find to agree with reason and experience, as conducive to the good and benefit of one and all and of the world at large, accept only that as true, and shape your life in accordance with it.

Buddhism is called an upāya ("expedient means"), like a boat to take you to the other side of the river. The goal is not to carry the boat on your back further inland. There is no reason or scripture that prevents modern science to be an upāya as well, although it would mean "letting go" of some of the preconceptions that Buddhist scripture has via-a-vis, for example, neuroscience.

Buddhism states that some forms of consciousness are not dependent on the physical body. Neuroscience has proven beyond any doubt that this is impossible. This is why Buddhism is and will always be experiential: you cannot just be told the true nature of self, as this needs to be conveyed in language (be it human or mathematical), and this is totally different to a human being from experiencing the true nature of self.

Conflicts such as these between Buddhist doctrine and science pale in comparison to what Buddhism and Neuroscience have discovered independently and agree on: the illusion of self, the constant flux of brain and body, and that cognitive faculties are not fixed, but can be enhanced.

Science has the exact same challenge as Buddhism in conveying these findings: anything that relates to the psyche has to be experienced on an individual level to truly understand this, even if we can formulate theories and equations for the process. It's like the difference between looking at a map and walking a road depicted on that map.

Q: How do we know attaining an internal state is possible?

A: By attaining the internal state.

The ultimate Truth is beyond words.

The Way is wordless.

→ The Zen Teachings Of Bodhidharma - Translated by Red Pine

https://webcomicname.com/post/183722270609

When the eightfold path arise together in one moment, there is no doubt like that anymore.

You can say you are doing the best every time, but it isn't real. You just can't see the better which you can do, so you decide you are doing the best.

As you have known from the scientist that you need to analysis every thing as the smallest elements, eg. molecule, atom, particle, to understand their relations and get the reality.

That is same in Sutta and Abhidhamma.

So, if you can't see and abandon even only one wrong view of trillion minds arising in a second, you are not Sotapanna.

First, something to contemplate: Modern Science, as a human endeavor, is based upon the idea known as Verificationism. This states that only facts verified through empirical evidence—based ultimately on our senses and their modern technological adjuncts—can be considered to be true. Everything else, including ideas coming from metaphysics and religion, are just beliefs found to be emotionally appealing.

And because Verificationism implies that the empirical evidence must be ‘objective’ (so that it can be verified by others) many ideas, especially those coming from metaphysics and religion, which Science holds cannot be empirically evidenced, as well as those related to interior personal experiences, such as those found in meditative practices, can never be verified to be true.

So if you are hoping for “scientific” evidence that liberation is possible you will be frustrated. Modern Science doesn’t operate there—by choice.

But here is one interesting truth: no scientist has ever verified verificationism. That means no one has ever proven that the central idea underlying the scientific method is valid. This idea that only something that is verified by empirical evidence can be true is just a belief that has emotional appeal to scientists.

And if you truly contemplate the logical structure of this belief, you will find that the aspects, processes, and rules of ‘reality’ must be true whether or not a human being has verified them to be true. That is, Truth must be primordially present for a thing to be verifiable. And thus, we find a universe of otherwise unverifiable truth opening up for us, because there is more Truth in reality than Science can verify, even if scientists wanted to do so.

Another aspect of the answer to your question is that there is an irreconcilable divide between Modern Science and Buddhism in their understanding of what mind is. For scientists in general, the mind is just a word for the biochemical operations of the brain. For Buddhists, the brain, body, and all perceptions are activity that together are called mind, and this includes all the biochemical operations of the brain. Thus two totally different and opposing understandings of what mind is.

And so you ask how we know that complete liberation from dukkha is possible. The first part of the answer is that because suffering arises due to causes and conditions related to mind, and we are specifically training ‘our mind’ to remove the causes and conditions of suffering, it would be illogical and incoherent to assert that our practices—if conscientiously applied—did not end our suffering.

The second part of the answer is because we have the testimony of a myriad of enlightened beings who have all attested to having gone through this process of mind-training and the liberation from suffering that it brings, we would be insincere if we complained that there is no proof of such liberation. And of course, anyone who doubts the words of these enlightened beings are invited—as a fundamental aspect of their teachings—to see for themselves if they are not true, by applying the methods to their own mind.

Third, we have detailed training documents that have been honed over the course of millennia, which all describe the same ultimate accomplishments, even though they describe the stages of the process in different terms, and different degrees of ‘granularity’ of the stages. It would be disingenuous of us to argue that they do not—together—verify the resulting accomplishment.

And fourth, unlike Science, which operates on phenomena at scales beyond our capability to directly experience ourselves, the liberation from suffering (and the causes of it) is entirely accessible to each and every one of us, without any technological augmentation or equipment needed.

This is how any sincere individual would know the truth of liberation. Thus, it is not a belief, nor is it just an emotionally attractive idea without proof. It is True before we examine it, it is true because of all the testimony and documentation supporting it, and it is provable by each and every one of us, if we so desire.

How do we know attaining complete liberation from dukkha is possible?

That's a good and important question.

I think when starting out on the Buddhist path and one doesn't yet have much wisdom from insight meditation practice, it's more of a leap of faith.

One can read in books, listen to Dhamma talks or be taught by teachers and practitioners, that there's a Dhamma called Nibbana, an existing reality that doesn't arise or cease, that one can experience by following and cultivating the Noble Eightfold Path to its full maturity.

Sounds too good to be true, right?

The thing is, we can't really know before experiencing it by ourselves, by gaining sufficient wisdom from meditation practice. Nibbana cannot be understood intellectually due to it's depth and profundity. So it's a leap of faith until one can become a first hand witness and gain insights into how reality works. At some point on the path, when the mind has been cultivated to a certain point, it will begin experiencing cessation, i.e. the mind goes to Nibbana. In beginning only for short amounts of time, later it can stay in cessation for hours or days.

Please don't be satisfied with my words. If you really want to know the answer to your question, go practice the Noble Eightfold Path and see what happens. I think that's the best answer I can give.

When we practice by sitting in meditation, we will (in a fairly short time) reach a state where tanhā and dukkha 'spontaneously' disappear, if only for a moment or two. I'm not even talking about a true satori experience. I just mean a moment where the waters of the mind grow calm and still — where we are not doing or thinking anything, because there's nothing particular to do or think — a lacuna after the mind-waves have ebbed away, and before they come rolling back in.

By that we know that tanhā and dukkha can cease. What more epistemic justification do we need?

Of course, there's the practice... We have to broaden and deepen that lacuna within our meditation; we have to learn to extend it beyond out meditations into our convention al lives. There's an element of faith that it can be done, obviously, but it isn't faith in some externality. It is faith in ourselves, and our ability to work with that spaciousness.

the diminishing of the presence of tanha leads to the diminishing of the presence of dukkha... the extension of this principle... via inductive reasoning... applied all the way until complete eradication of dukkha...

Let's reason logically:

We know that everything in life of a sentient being can be subsumed under subjective experience. For a sentient being subjective experience is life, subjective experience is what matters.

All subjective experience can be broadly categorized as either "rather good" ("nice", "right", "satisfying", "positive", "pleasant", or at least acceptable/neutral) or "rather bad" ("nasty", "wrong", "annoying", "negative", "painful" etc). Therefore, for sentient beings, the character of their subjective experience is the essence of the difference between the Good and the Bad.

Now, subjective experience is made of the mind, it is a state of mind. There's no subjective experience outside of mind. And the nature of mind is representation, it is made of information that stands for something. Therefore subjective experience is a flow of interpretation generating a stream of representations. How can it be good, right, pleasant or bad, wrong, painful?

The nature of interpretation is such that it allows no contradictions. Contradicting evidence interferes with interpretation. Contradicting conclusions are a failure of interpretation. Therefore any such interpretative contradictions are harmful to the very process of interpretation which is the nature of the subjective experience.

Therefore it is the interpretative contradictions that make the difference between the good, right, pleasant, harmonious experience and the bad, wrong, painful, discordant experience.

Now, the interpretative contradictions come from a clash of two or more incompatible representations pertaining to the same subject. The way we give rise to interpretative contradictions is twofold. The coarse ones are created by getting into a circumstance of life with inherent contradiction between the elements of the situation. The subtle ones are generated directly in the mind.

According to the Buddha, the coarse ones are eradicated through the consistent practice of social and behavioral ethics - choosing one's actions such as to not create causes for discordant circumstances - while the remaining subtle ones are eradicated in meditation, by mastering one's attention and interpretation mechanisms as to prevent all kinds of inner discord.

If this were all there was to Buddhism, your doubt would be justified. Indeed, how can we know with absolute certainty that it is possible for an individual sentient being to reach a state where their mind, their process of interpretation, will no longer give rise to any and all interpretative contradictions caused by incompatible representations? Isn't the very nature of mind being a product of representations - simplified and partial by their very nature - inevitably leads to arising of conflicts? Isn't representation inherently conflict-prone?

To answer this question we need to get very clear about the mechanism behind the process of interpretation. Interpretation is an act of translating one or more signs into a category of experience this sign (or signs) signify (or represent). These links between signs and the categories, as well as the signs and the categories themselves, is something we learn from experience and absorb from our parents and other people as well as from various media.

As a sentient being accumulates these signs, categories, and interpretations - it connects them together into one semiconsistent structure called "everything I know about the world". The same totality of one sentient being's representations, with all its opinions and interpretations is what makes up its personality. Personality is the other side of the coin of "the world as we know it". The root of personality is Ego, the inferred notion that "I am the subject and my experience is consistent". In other words, Ego is this assumption that our interpretation and therefore our experience is done from a certain point of view, a certain perspective. 'I am' - thinks the ego - 'therefore my opinions and my actions have an inner logic to them'. The job of ego is endless self-rationalization in order to prove its own existence.

Because ego is all about self-rationalization, it must maintain a semblance of consistency at all cost. Guess what, this dependency on consistency is exactly what makes ego vulnerable to contradicting interpretations! So whenever we have a case of incompatible representations, it is the ego that suffers! It is the ego that is hurt by the conflict! In and off themselves the contradicting interpretations are just that, a logical contradiction. It is hurtful only because we identify with our process of interpretation, we declare ourselves to be the interpreter.

And herein lies the answer to your question. We know the complete liberation from dukkha is possible because we know it is not to be achieved by the process of asymptotic approximation of the conflictless harmonious state. (Although as shown by the Buddha, reducing the outer and inner conflict goes a long way towards achieving the clarity of mind required for the final realization.) Instead, it is achieved by removing the very foundation of conflict - the grasping at a point of view called "I". When this is done, resulting in the sentient being having no point of view, no position - the representations of the world continue clashing as before, but for the one like this there's no more conflict.

In summary, we don't need mathematical induction too see that complete liberation from dukkha is possible. What's necessary and sufficient is to understand the second noble truth: the arising of dukkha happens due to grasping, the root of grasping is the ego's demand for continuous consistency, therefore letting go of that demand, i.e. letting go of identification with one's knowledge, view, position, perspective, in short, letting go of self-identification - is the final liberation.

the Buddha: Well said, well said! That's right. You have understood it perfectly. You have understood the nature of mind. You are ready to become the next Buddha of this world.

I: Suuuure, and the elephants are actually pink!

the Buddha: That's right. Elephants are actually pink. Everything is pink when you understand the nature of mind.