what is real?
Mystics claim, whatever we experience as our reality, is depending very much on the experiencer. And indeed, if we take the mystical approach and look, who is experiencing, we cannot come to an unambiguous conclusion. It's impossible to define clearly with words, who we are. What we can do, however, is to exclude, what we are not, for example by stating
"You are never, what you think you are, and reality is never, what you think it is."
Why? Because any thought that appears on our inner screen is a representation of a phenomenon or a group of phenomena of your sensual impressions and not the phenomenon or the group of phenomena itself. The mind never deals with the world out there directly, it is identifying and naming objects and thus creating internal symbols, words and sentences from the impressions it receives through the senses. The objectivity of our world is imaginary as we are only dealing with interrelating symbols within ourselves, which are forming thoughts and emotions, which are transformed into chains of thought in our brains. These processes are happening so fast, that we usually don't realize their complexity and consequently we also fail to notice that each perceiver has his own unique version of an object.
The ancient yogis and rishis of the East understood the deceptive illusionary character of the world of phenomena through self observation and created the terms maya or samsara for the fleeting world of material and virtual objects.
In natural sciences on the other hand, we took the world as fairly static, solid and objectively real for many centuries . But since Einstein, Heisenberg, Bohr and the development of quantum physics the scientists and mystics have been coming very close to each other. Here are a few examples from the world of science, to make it clear, that there is also no absolute truth in science:

Anybody will agree that 1+1=2, right? If you, however, allow infinite as a value, you can make an equation ∞+1=∞, because infinite is always infinite, whether you add something or take something away. Then you take ∞ on both sides away and you're left with 1=0 and the whole system comes crumbling down! That's why the mathematicians have to exclude infinite and zero for certain operations, because math will not work otherwise. Which means, however, that mathematics is only true within a certain defined range and not absolutely, universally and indefinitely. When we look into realms beyond the mind the defined range is not valid any longer. Even Stephen Hawking, a famous contemporary genius of physics, admits in one of his books, that all of our scientific statements are not THE truth, but only auxiliary devices, as long as they give us a reasonable explanation and allow certain predictions about a phenomenon. Therefor there cannot be a guarantee that a formula, which works today, will also work tomorrow.


(excerpts from Wikipedia, full article see here: the coastline paradox)
If we are given the task of measuring such an object, we have to decide, which method is appropriate for our purpose. In case we want to make a bicycle trip along the coast of the main British island, we will probably not measure each stone on the shore, but rather we will measure the length of the roads in the vicinity of the coastline. The difficulty of multiple solutions arises not only in regard to the coastline of an island, but to many objects and processes in our world. In order to preselect from the infinite options, which we are facing in every moment of our lives, we are developing certain structures, routines and beliefs, which in turn influence our perception of reality.
Modern science confirms the view of the mystics, that we create our reality through our means of perception individually and subjectively. There might be a big overlap between your reality and your friends reality, and all societal groups have certain reality overlaps within their members, but ultimately your reality is unique. Each sentient being, each reflector of existence operates within their own reality and their own universe. If you take in account additionally that each being creates a new universe every moment (again with large overlaps from the universe of the moment before, but still fresh and new), it is not surprising that there is big chaos everywhere. In fact it is truly amazing that anything works at all! Yet, for reasons unknown, extremely unlikely and complex phenomena are continuously appearing (and disappearing) on our planet. And we actually have no chance to find out, why it's all happening, as in the process of observation reality is already changing and being recreated. All we can say, is, that there is a something, a vague potentiality, an energy flow, which becomes a temporary actuality through being observed.
Let's look at our planet, where we walk around every day. Picture 1 is Makena beach on Maui with wonderful golden sand. Picture 2 is a little bit of this sand in a close up. There are about 2500 grains of sand in picture 2:


With the image of this huge pile of sand in mind, let's take a look into the sky. The picture shows just a small portion of the night sky with the constellation Orion, a part of Taurus and a lot more celestial bodies from our galaxy:
(Picture by Mahendra Myshkin)
There are a lot of little white dots, the stars, visible with the naked eye. But many, many more, when looking through a telescope. 100 to 400 billion stars in our galaxy are the present estimate. Scientists have calculated that the number of stars in the known universe, which consists of approximately 2 trillion galaxies, is even bigger than the number of grains in our huge pile of sand. Even though the total amount of stars can be only a rough estimate, certainly a few more zeros must be added to our above number of sand grains.
Our earth is very, very tiny in comparison with the vastness of the universe and humans are even tinier.
But before you are overcome by depression and emotions of complete smallness, take a look at our pile of sand again and single out one grain only. Imagine taking a tiny chisel and hammer and splitting it up into it's atoms, you will be getting an even larger number of atoms within one tiny grain than the number of stars in the universe.
(Picture retrieved from enigmatics)
Our bodies are more than a million times bigger than a grain of sand. So we are incredibly big in relation to atoms and particles.
The picture shows a model of silicon dioxide molecules (SiO2), which are the main components of a grain of sand. We have no means of taking pictures of these structures, they are way beyond the range of electronic microscopes. But from experiments we know, that the infinitesimal structure should look somehow like this. The light green balls represent the silicon atoms, each one being connected with two of the smaller dark green oxygen atoms.
You may see now, how easy it is to feel superior or inferior just by choosing to compare the size of your body-mind-system to atoms or to stars.
But in our day to day life we don't need to deal with galaxies or atoms (unless you are an astronaut or a nuclear physicist), instead we only have to deal with a range of medium sized phenomena ranging in most cases from a grain of sand to our sun, the area in which our practical lives are taking place. If it wouldn't be so, life would be impossible. We can't be simultaneously aware of whole the macrocosm, where a black hole might be gobbling up a whole galaxy millions of light years away, and of the microcosm in our body, where zillions of particles are madly dancing around almost unnoticed, while we are trying to get our jobs done here.
