> 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?

I've read somewhere that it takes 10k hours to master anything. Let's consider example of a musical instrument, say Piano, that you're learning. It will take you 10k hours of sincere practice to reach to a state of mastery in which playing piano will be a subconscious, effortless act, you'd be able to listen to any song and start playing it. However, this effortless will be preceded by state of conscious competence in which you can play a song after listening it, but it takes some effort and even then, it's not perfect. You know you're progressing but you're not there yet. You can see the goal but you also know that it'll take good effort to reach there.

Another advantage you have at this stage is you can appreciate the expert player from a charlatan. It's not easy to fool you anymore.

So, you can consider me that 3k hours pianist re meditation. I started practicing meditation in 2014 inspired by this HN post https://news.ycombinator.com/item?id=6910041

>> The Really Unexpected My forehead caught on “fire”. No--really. This was the single strangest event of the entire challenge, and I have no explanation for it, but what took place was that after about 30 days, the centre of my forehead felt like it was emitting or radiating what I can only describe a kind of heatless, lightless flame.

I started in June2014 and my first experience happened in about a month. I've never stopped meditating daily ever since (apart from some not-so-frequent days of urgent work/function/illness) (I try to do it in three sessions in morning/evening/night)
The experiences continue to come. Then if you read books by expert meditator, you'll be able to relate their experiences with yours.

> 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?

Why do you believe such a claim? Let that person demonstrate it if he's so claiming. You don't have to believe anything or anyone. But at the same time, you shouldn't reject something without giving it a chance. Both of these are functions of a conditioned mind blinded by a sense of superiority that what it knows is the truth and that it cannot be wrong.

ON a related note, the problem for spirituality is that people get attracted to it by these stories of wonderful powers that they can gain, and lose the sight of true goal of Yoga: to reach to a state of union with one's eternal, imperishable atman (soul). That's actually a good test of expert: he will not sell meditation or other practices as a means to attained powers. He knows such powers (even if considered possible for a moment) are a hindrance in awakening and these are just another form of material entertainment for the conditioned mind while the goal is to rise above conditioning to experience state of oneness with the universe; with atman. Once you have become that, you can yourself verify if you really can get these powers, chances are, you will no longer be interested in them.

> 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.

Who says you won't need rest? As long as you're in this physical body, you'll need rest. But the source of your joy will be within rather than dependent on external factors like money, appreciation, fame, success ETC. which keep on changing. You'll be able to maintain your state of inner peace and bliss even in absence of these.