user760: All the answers to the question about the living enlightened people suggest that talking about one's enlightenment is taboo, so if somebody claims to be enlightened, he probably is not.
Why doesn't this reasoning apply to the Buddha? After all, he claimed himself to be englightened (for example, in Dhammacakkappavattana Sutta).

user295: Some people may believe so to warring degrees of confidence, but this confidence only becomes unshakable at stream entry. When practicing the Dhamma you start seeing the milestones in the journey your confidence in reinforced and at stream entry it becomes unshakable.
If Buddha has shown the path to Nirvana and when you follow it you get there then you can be sure that the person knows.

user1058: The overall idea seems to be that if a being is actually enlightened, then this fact will be apparent without ambiguity to all who interact with that being.
As far as the Buddha himself is concerned, according to the canon, those hostile to him never managed to best him in debates (thus never managed to dent his teaching) and those symphathetic to him always recognized his greatness and at many occasions decided to follow him (thus affirming his extraordinary nature). The canon tells us with this that the Buddha could, so to speak, "talk the talk" but also "walk the walk", and do this in any situation he could encounter. It is the profundity of his teachings that leads Buddhists to place their trust in the Buddha's Enlightened nature.
From this perspective making the claim was like a random person making a banal statement such as "I am a human being" for him.  
If there are disciples that attain Enlightenment during their current lives, why shouldn't they also make the same declaration? There might a very simple and pragmatic answer to this. The Buddha was in the process of diffusing the Dhamma to a world that had lost those teachings since a long, long time ago. Talking about his own Enlightenment, he was giving the explanation of why these teachings were worthwhile and why he should be the one listened to among the multitudes of other teachers of the era.
What necessity has there been for practitioners to talk about their own achievements since the Buddha's death? The Dhamma has been thaught to many and codified, and the sangha was structured in a democratic and pretty much egalitarian way. People claiming Enlightenment within reason or not could/can form magnetic poles and attract disciples to themselves and away from each other, effectively sowing completely unnecessary discord within the community. It's completely unnecessary and is something that only a non-Enlightened person seeking self-interest would do.
As for the matter of the Buddha's disciples talking about their own attainments, we must not forget that
a) the Buddha was still alive, which nullified chances of successful false claims and
b) the people they were talking with were familiar with the concepts talked about and the terms used. It was a time where spiritual pursuit was seen as something perfectly real and valid in the eyes of society, and they were familiar with what that pursuit entailed. It isn't so in our modern era and Western/Westernized societies, where spiritual pursuit is not seen as something "normal" and the elements of Buddhism are foreign to the people.

user16635: This is merely a matter of the delusory power of words. When the Buddha was teaching, he used the word 'enlightenment' to express an inner state — an attitude towards the world — that he was trying to convey to others. The word had no cachet: no prestige or significance beyond the effort to describe an ineffable experience in language. He and his followers merely used it to discuss progress on the path. 
As the philosophy extended and developed, however, the concept of 'enlightenment' shifted away from being a mere description of an attitude, and became more and more a label for a 'thing' that ought to be 'achieved.' Things and achievements have social value in the world. They are commodities to be bought, sold, or exchanged for other things of value; they are firm anchor points for identity and  attachments. Attaching oneself to such a concept runs against the intentions of the practice.
The word 'enlightened' changed over the centuries from being used as an adjective to being used as a noun. To the extent that we can still use it in the adjectival form — as a description of a way to be — it's still a fine word. But using it as label for an attainment, a matter of pride and value, will lead both the teacher and the students astray.

user179: The taboo of talking about or claiming ones own enlightenment is something which has been established by the monastic order. 
Talking about ones own attainments to lay-people or even non-buddhist is considered not done.
The only monastic rules I could find that resembles such a rule is these two:

A bhikkhu who pretends to have experienced jhāna attainments or the
  ariyā state without having experienced these, commits the pārājika 4.
  However, if the person whom the bhikkhu is addressing does not know
  the meaning of these words, he commits a thullaccaya.

source: http://en.dhammadana.org/sangha/vinaya/other_faults.htm
and:

Not to announce to a layman a realisation that has been achieved. If a
  bhikkhu announces to a layman or to a sāmaṇera, a realisation
  partaking with a jhāna nature or with a stage of ariyā, and this
  realisation has genuinely been achieved, he commits a pācittiya.
On the other hand, a bhikkhu who makes such a declaration, while
  knowing it to be false, commits the pārājika 4. A bhikkhu must avoid
  making his attainments known, even to other bhikkhus. Apart from four
  exceptions when they can do so, ariyās never unveil their
  realisations:
Under a violent threat.
Undergoing an oppressive and virulent lack of respect.
A t the time of passing away.
To reveal it to his preceptor or to a fellow bhikkhu who does a similar practice.


source: http://en.dhammadana.org/sangha/vinaya/227/92pa.htm#ch-----8
The rule only applies if one lies about attaining such, or isn't aware about what he is in fact claiming.
The second rule only applies when spoken to lay people.
Also, in the Buddhist text and stories the disciples of the Buddha also speak freely about their attainments, powers and even if they have achieved enlightenment.
The other monks only seemed to protest if they didn't believe the claimant and asked the Buddha to verify, which in most cases he did.
So the rule that one must never speak of ones own attainments or claim enlightenment seems to be later added and unwritten.

user43: I said "bragging of one's achievements is bad tone" and you turned it into "talking about one's enlightenment is taboo" :) It is very easy to fall into extremes, isn't it?
"If somebody claims to be enlightened, he probably is not" -- here is a simple explanation. Among other things Enlightenment involves shedding the mistaken identification with the illusory "I". So once Enlightenment has been revealed, it seems rather silly to say "I am Enlightened" -- because this "I" is a fiction.
Plus, Enlightenment is self-existing, it does not depend on being attained or not. The metaphor for this is sun above the clouds. Once you remove the clouds, you can see the sun, but the sun is always there, before and after. This is another reason why saying "I have attained Enlightenment" is silly.
As Chogyam Trungpa Rinpoche said:

Buddhism says that confusion has to be dispelled and that there should
  be realization beyond confusion. It is based on the idea of
  transcending the highest ideals of the human mind completely, which is
  called enlightenment. Once you dissolve, once your particular
  expectations dissolve, that is liberation or enlightenment. Since
  enlightenment is based on dissolving the ego and its expectations, it
  has been said that you cannot watch your own burial, and you cannot
  congratulate yourself on becoming the first buddha of the age or the
  first buddha of New York.

Buddha claimed Enlightenment solely in order to help his students gain confidence in his teaching. He knew very well the extent to which the statement "I am Enlightened Buddha" can be true.
Then why don't modern teachers claim Enlightenment to help their students gain confidence? As I explained in Is Satori the same as Enlightenment? and Enlightenment vs nibbana/nirvana, most people achieve "sudden insight / gradual cultivation". With gradual cultivation, you can never claim 100% Enlightenment, because in this case Enlightenment is asymptotic. All we can definitely claim is the insight.

760: <p>All the answers to the question about the <a href="https://buddhism.stackexchange.com/questions/3058/are-there-any-living-enlightened-people/3352">living enlightened people</a> suggest that talking about one's enlightenment is taboo, so if somebody claims to be enlightened, he probably is not.</p>

<p>Why doesn't this reasoning apply to the Buddha? After all, he claimed himself to be englightened (for example, in <a href="http://www.accesstoinsight.org/tipitaka/sn/sn56/sn56.011.harv.html" rel="nofollow noreferrer">Dhammacakkappavattana Sutta</a>).</p>
 295: <p>Some people may believe so to warring degrees of confidence, but this confidence only becomes unshakable at stream entry. When practicing the Dhamma you start seeing the milestones in the journey your confidence in reinforced and at stream entry it becomes unshakable.</p>

<p>If Buddha has shown the path to Nirvana and when you follow it you get there then you can be sure that the person knows.</p>
 1058: <p>The overall idea seems to be that if a being is actually enlightened, then this fact will be apparent without ambiguity to all who interact with that being.<br>
As far as the Buddha himself is concerned, according to the canon, those hostile to him never managed to best him in debates (thus never managed to dent his teaching) and those symphathetic to him always recognized his greatness and at many occasions decided to follow him (thus affirming his extraordinary nature). The canon tells us with this that <strong>the Buddha could, so to speak, "talk the talk" but also "walk the walk"</strong>, and do this in any situation he could encounter. It is the profundity of his teachings that leads Buddhists to place their trust in the Buddha's Enlightened nature.<br>
From this perspective making the claim was like a random person making a banal statement such as "I am a human being" for him.  </p>

<p>If there are disciples that attain Enlightenment during their current lives, why shouldn't they also make the same declaration? There might a very simple and pragmatic answer to this. The Buddha was in the process of diffusing the Dhamma to a world that had lost those teachings since a long, long time ago. Talking about his own Enlightenment, he was giving the explanation of why these teachings were worthwhile and why he should be the one listened to among the multitudes of other teachers of the era.<br>
What necessity has there been for practitioners to talk about their own achievements since the Buddha's death? The Dhamma has been thaught to many and codified, and the sangha was structured in a democratic and pretty much egalitarian way. People claiming Enlightenment within reason or not could/can form magnetic poles and attract disciples to themselves and away from each other, effectively sowing completely unnecessary discord within the community. It's completely unnecessary and is something that only a non-Enlightened person seeking self-interest would do.<br>
As for the matter of the Buddha's disciples talking about their own attainments, we must not forget that<br>
<strong>a)</strong> <em>the Buddha was still alive, which nullified chances of successful false claims</em> and<br>
<strong>b)</strong> <em>the people they were talking with were familiar with the concepts talked about and the terms used</em>. It was a time where spiritual pursuit was seen as something perfectly real and valid in the eyes of society, and they were familiar with what that pursuit entailed. It isn't so in our modern era and Western/Westernized societies, where spiritual pursuit is not seen as something "normal" and the elements of Buddhism are foreign to the people.</p>
 16635: <p>This is merely a matter of the delusory power of words. When the Buddha was teaching, he used the word 'enlightenment' to express an inner state — an attitude towards the world — that he was trying to convey to others. The word had no <em>cachet</em>: no prestige or significance beyond the effort to describe an ineffable experience in language. He and his followers merely used it to discuss progress on the path. </p>

<p>As the philosophy extended and developed, however, the concept of 'enlightenment' shifted away from being a mere description of an attitude, and became more and more a label for a 'thing' that ought to be 'achieved.' <em>Things</em> and <em>achievements</em> have social value in the world. They are commodities to be bought, sold, or exchanged for other things of value; they are firm anchor points for identity and  attachments. Attaching oneself to such a concept runs against the intentions of the practice.</p>

<p>The word 'enlightened' changed over the centuries from being used as an adjective to being used as a noun. To the extent that we can still use it in the adjectival form — as a description of a way to be — it's still a fine word. But using it as label for an attainment, a matter of pride and value, will lead both the teacher and the students astray.</p>
 179: <p>The taboo of talking about or claiming ones own enlightenment is something which has been established by the monastic order. 
Talking about ones own attainments to lay-people or even non-buddhist is considered not done.</p>

<p>The only monastic rules I could find that resembles such a rule is these two:</p>

<blockquote>
  <p>A bhikkhu who pretends to have experienced jhāna attainments or the
  ariyā state without having experienced these, commits the pārājika 4.
  However, if the person whom the bhikkhu is addressing does not know
  the meaning of these words, he commits a thullaccaya.</p>
</blockquote>

<p>source: <a href="http://en.dhammadana.org/sangha/vinaya/other_faults.htm" rel="nofollow">http://en.dhammadana.org/sangha/vinaya/other_faults.htm</a></p>

<p>and:</p>

<blockquote>
  <p>Not to announce to a layman a realisation that has been achieved. If a
  bhikkhu announces to a layman or to a sāmaṇera, a realisation
  partaking with a jhāna nature or with a stage of ariyā, and this
  realisation has genuinely been achieved, he commits a pācittiya.</p>
  
  <p>On the other hand, a bhikkhu who makes such a declaration, while
  knowing it to be false, commits the pārājika 4. A bhikkhu must avoid
  making his attainments known, even to other bhikkhus. Apart from four
  exceptions when they can do so, ariyās never unveil their
  realisations:</p>

<pre><code>Under a violent threat.
Undergoing an oppressive and virulent lack of respect.
A t the time of passing away.
To reveal it to his preceptor or to a fellow bhikkhu who does a similar practice.
</code></pre>
</blockquote>

<p>source: <a href="http://en.dhammadana.org/sangha/vinaya/227/92pa.htm#ch-----8" rel="nofollow">http://en.dhammadana.org/sangha/vinaya/227/92pa.htm#ch-----8</a></p>

<p>The rule only applies if one lies about attaining such, or isn't aware about what he is in fact claiming.</p>

<p>The second rule only applies when spoken to lay people.</p>

<p>Also, in the Buddhist text and stories the disciples of the Buddha also speak freely about their attainments, powers and even if they have achieved enlightenment.
The other monks only seemed to protest if they didn't believe the claimant and asked the Buddha to verify, which in most cases he did.</p>

<p>So the rule that one must never speak of ones own attainments or claim enlightenment seems to be later added and unwritten.</p>
 43: <p>I said "bragging of one's achievements is bad tone" and you turned it into "talking about one's enlightenment is taboo" :) It is very easy to fall into extremes, isn't it?</p>

<p>"If somebody claims to be enlightened, he probably is not" -- here is a simple explanation. Among other things Enlightenment involves shedding the mistaken identification with the illusory "I". So once Enlightenment has been revealed, it seems rather silly to say "I am Enlightened" -- because this "I" is a fiction.</p>

<p>Plus, Enlightenment is self-existing, it does not depend on being attained or not. The metaphor for this is sun above the clouds. Once you remove the clouds, you can see the sun, but the sun is always there, before and after. This is another reason why saying "I have attained Enlightenment" is silly.</p>

<p>As Chogyam Trungpa Rinpoche said:</p>

<blockquote>
  <p>Buddhism says that confusion has to be dispelled and that there should
  be realization beyond confusion. It is based on the idea of
  transcending the highest ideals of the human mind completely, which is
  called enlightenment. Once you dissolve, once your particular
  expectations dissolve, that is liberation or enlightenment. Since
  enlightenment is based on dissolving the ego and its expectations, it
  has been said that you cannot watch your own burial, and you cannot
  congratulate yourself on becoming the first buddha of the age or the
  first buddha of New York.</p>
</blockquote>

<p>Buddha claimed Enlightenment solely in order to help his students gain confidence in his teaching. He knew very well the extent to which the statement "I am Enlightened Buddha" can be true.</p>

<p>Then why don't <em>modern</em> teachers claim Enlightenment to help <em>their</em> students gain confidence? As I explained in <a href="https://buddhism.stackexchange.com/a/2813/43">Is Satori the same as Enlightenment?</a> and <a href="https://buddhism.stackexchange.com/a/3074/43">Enlightenment vs nibbana/nirvana</a>, most people achieve "sudden insight / gradual cultivation". With gradual cultivation, you can never claim 100% Enlightenment, because in this case Enlightenment is asymptotic. All we can definitely claim is the insight.</p>
