In one word: selflessness. Acts of a truly enlightened or awakened being will be selfless. He has already realized the futility of doing actions for sense gratification. Please note the word realized. Intellectual understanding is different from realization. With the former your subconscious mind continues to propell you to strive for fulfilling selfish desires while realization will clean the slate. When we study the lives and sayings of great people, we find in them the quality of selflessness, no matter what their religious or cultural background might be.
There are also physical signs. There are no unnecessary bodily movements. The speech also becomes pleasing. Gestures are graceful. Such a person seems to emit a unearthly glow. People experience unconditional love and calmness in his presence. However physical signs aren't the definitive teller as most of these can be imitated for a limited public appearance. Hence the most important factor is the conduct.
That’s still not answering my question. How do I tell the difference between myself achieving enlightenment and merely having an opinion that I have achieved it?
Things you describe are perceived subjectively, so they can also be victims to my brain deluding myself.
> How do I tell the difference between myself achieving enlightenment and merely having an opinion that I have achieved it?
How would you describe a state of mind in which you remain thoughtless as long as you want? Thoughts will only arrive in your conscious mind when you summon them and you can hold a thought as long as you want. You remain perfectly peaceful, tranquil without blabbering and urges of the mind without exerting as in meditation. Meditation is no longer an act but a state of your mind.
When your mind is perfectly under control without effort, you have become awakened (or enlightened), because now you truly possess a free will in the truest sense of the word. Earlier when your mind was in control, your innate tendencies were driving your actions, based on external stimuli. Anger, greed, lust, envy, fear and other negative emotions thrive in such a state of mind naturally and one has to exert to check them.
I'd urge you to try concentrative meditation, wherein one tries to hold a thought (could be visualizing a form, or listening to a sound ETC) and see the power of conditioned mind. Observe how long you can hold it. For instance, if you're visualizing a form, you may discover that within matter of few seconds it starts fading, dancing or completely gone. Similarly If you are meditating on sound, you will find that within few seconds your mind has distracted and you have to exert to retain your focus. The mind is not in your control and such a conditioned mind can form opinions and dilute you. But an enlightened mind, perfectly in control cannot have delusion and ever lives in present moment. Opinions and judgement are tools of a conditioned mind, ever fearful and constantly striving to ensure survival of the body.
That said, I'm not yet an enlightened being; I'm striving for it by walking path of meditation, kindness and chanting [0]. I do have experiences and glimses confirming most of what I've written, but I have not attained the final state yet. If you're truly curious and want to read, learn and practice more about this, I'd encourage you to read Om Swami's books. The one on meditation [1] takes you through the journey of a meditator with states and stages of mind and awareness that you'll find intriguing and hopefully interesting to pursue. Simple yet precise methods and practices have been given along with a method to measure one's progress.
First of all, how do you know that all these people claiming enlightenment - exactly as you describe it - aren't all full of shit?
Secondly, let's say it's all true. Why is that so desirable?
> But an enlightened mind, perfectly in control cannot have delusion and ever lives in present moment
It's perfectly possible to live in the present moment and disregard the future even without meditation. That's not generally considered a good thing, though.
> Opinions and judgement are tools of a conditioned mind, ever fearful and constantly striving to ensure survival of the body.
Yes, your body has adapted to survival. What's wrong with that, why do you want to turn that off? You'll die anyway, are you really that impatient?
I guess if you're somehow in constant terror about the plight of existence, that might be a useful skill to have. Otherwise, I'd rather learn something else.
> First of all, how do you know that all these people claiming enlightenment - exactly as you describe it - aren't all full of shit?
Exactly as in any other field of expertise. Through your practice, knowledge/experiences you gain from that practice. Mere reading the books doesn't take one far in any field.
> Secondly, let's say it's all true. Why is that so desirable?
Who says it's desirable to everyone? It's individual's choice. If you get pleasure in learning something else, feel free to do that.
But someone might also want to go to the source of pleasure so he can maintain state of pleasure at all times regardless of circumstances outside, meditation is one sure way to that. Just like a hard core engineer may want to know how the whole thing works down to transistor, some people eventually get this desire to experience their whole being down to one's soul and even the super soul. Such people aren't satisfied being mere servant to the needs of body or mind for whole of their lives. They want to experience the eternity if there's such a thing. It's an arduous but a rewarding journey, with wonderful experiences at every little milestone on the path. But this thread isn't an appropriate place to write details about them.
Btw if you are thinking meditation or enlightenment means withdrawal from the world, or becoming something inert or passive, or stop enjoyment/learning, then you've not understood it correctly.
> Exactly as in any other field of expertise. Through your practice, knowledge/experiences you gain from that practice.
But as you said, you're not quite there yet. How do you know that what you described is really achievable? What else can you do but take other people by their word? Some people claim that through meditation, they could literally levitate. What's to stop anyone from just claiming something that's impossible to prove wrong?
It's not that I doubt meditation can have profound effects on one's psyche and well-being, but at some point I just don't don't buy it, like when you speak of a "constant state of pleasure". I don't think that's physically possible, at some point the receptors in your brain will need time to recover.
There are also physical signs. There are no unnecessary bodily movements. The speech also becomes pleasing. Gestures are graceful. Such a person seems to emit a unearthly glow. People experience unconditional love and calmness in his presence. However physical signs aren't the definitive teller as most of these can be imitated for a limited public appearance. Hence the most important factor is the conduct.