When people hear of buddhism and 'emptiness,' typically they will thing of a state of mind which is void of thought, void of emotion, void of, practically everything.
However, that's not the case at all. Emptiness is void of the *I*. It is emptying the I to the point where it is no longer a singular entity. A separate self, from everything, or anything that exists.
Like the flower analogy given above, here's the flower. It cannot possibly exist independently from the sun. It needs the sun to survive. It also needs water. It needs ground to be planted in. It isnt a matter of 'flower' and 'ground' and 'sun' and 'water.' We do separate these with mind, of course, sum of part things. The difficulty is bringing about the blurry line, wholeness of all things. But it can be done. "Earth" cannot exist without the sun, most would agree. But could the sun exist without the earth? Actually, probably not. Because if there was no earth, then its quite possible it could throw the entire solar system out of whack. Which would then, throw all the planets out of whack, and harmony. Our solar system would cease to be what it is. It wouldnt flow the way it would. Other planets could be thrown off their course, mercury might get thrown into the sun in a dramatic collision. The solar system could look like a pool table, with the cue ball shooting at it, and then it would be something else. The point is, each and every thing is dependent on something else. Thus, therefore, there is no 'independence.' Even the sun, the bold star of our solar system, needs all the planets to do their dance, in synchronicity. And if we broke it down even smaller, the sun needs us. For whatever reason, life is on the third rock. It exists, and does its whole flow. And even one tiny ant is part of it all and significant, because nothing in life is insigifnicant. An atom, is very small, but has value. However, it is not an independent thing. It still relies on other things for its existence.
Therefore, to achieve emptiness, is to dump the self, as an independent entity which is separate from anything. Our bodies are primarily made of water. If yous separated 'water' from 'self' you would fall to the ground a bag of bones, from dehydration. In essence you are water. You cannot exist independently from water. Water, isnt just a lake to sit by and gaze at. The same compounds of water that exist, flowing in that lake, exist and flow in you. Same thing, H2O. In the river, and you. Therefore, you are that. If you separated from that water, which flows in and out as you drink, which is retained so you may live, you'd die.
So if we eat an animal, eat meat, the meat is broken down into compounds, distributed into our bodies as we digest it. Now the animal, has undeniably become a part of us. If we thought back to how many animals we have eaten, what, thousands upon thousands, now we also have animals, who kept us alive. But they additionally, have become a part of us, per the distribution of proteins and vitamins and so forth. Course, this is physical. But the *I* is physical, as well. And Im very attached, my *I*, to my body, my 'self.' But where we are hindered, in letting 'go' in meditation, in getting empty, is the I clings, because it doesnt wish to realize, its not independent, from its environment. It is its environment. And just like creatures have no choice but to adapt to their environments for survival, we do this as well.
So as mind takes its journey, and the lines begin to blur more and more, its independence becomes shaken. So then it blurs, and it grabs onto it and clings. So what we do in meditation, basically is try to keep the focus, pry the fingers off the clinging one so it will let go.
Truth is the only way to really pry the fingers of the clinging one. Thats all that can be done. But wait, what is the buddha nature then? Buddhism, of course, teaches anatta, as no-self, even no-soul. But wait, there's an immortality though, a buddha nature. Whatever that is, thats the only 'ticket' to the freedom. That essence, is the only real thing we've got.
So emptiness is achieved but maybe getting the 'essence' is not. Because a paradox is, what on earth was the part that I was able to get empty? There is a cup, I emptied after all? And certainly mind can do it again and again. Get full, get empty. Its a valuable technique. Its a requirement. So we eliminate the self, and find the essence, there exists something which has no beginning, no end, which is deathless. It must be there, because if there is death, there's life. And all existence is a mere reflection of that. "Little us" is a reflection - of a bigger picture. We're the moon reflected in water. We're the cloud fleeting by, vapor, as buddha meditates - he's that.
So thats emptiness. Its not that there is 'no-thing' but its that the I doesn't exist, independently. It isn't a separate 'thing,' but its not a puppet on a set of strings either. Its the puppet, the strings, the puppeteer, the stage, the audience, the laughter, the applause, the seats in the auditorium, the curtain. And everything bleeds into each other.