Recently, I was thinking about;
“certainty” viewtopic.php?f=1&t=171217,
“reality” viewtopic.php?f=1&t=171190,
“disillusionment” viewtopic.php?f=5&t=171242,
and the “illusions” created by religions and ideologies (among others) viewtopic.php?f=5&t=171149.
While thinking about different types of “certainty”, and especially about the sense of certainty, as well as different types of “reality” and the sense and feeling of reality, I was glad to notice that the presence or the lack of certainty (and/or the sense, the feeling of reality/certainty) is directly related to the attachment/detachment and taking something (too) serious, sure, an/or important and thus pulled and tied down by particular perspective.
In short, the sense of reality/certainty is the key, the door for attachment/detachment or illusion/disillusionment.
I’m saying this because I had some experiences in loosing the certainty and the sense of reality of basic concepts like the concept of “separation/division” and the concept of “counting and numbers”, among others.
When these happened, things/ideas that was once sure and normal became just a perspective I could adopt for a while if I wanted, and thus something not very “certain” nor “real” to me, any more.
In retrospect, I think my life has been marked by big and small loss of “certainty”, like these.
And I now probably know the mechanism of this, more than before.
It has to do with the nature of the awareness and especially the nature of the focus of our awareness or the nature of our perspective. viewtopic.php?f=1&t=168136
It’s dividing nature, its nature to create virtual world when/while the perspective is maintained, these are the basic building block of our “reality”, which is made of layers of perspectives maintained by the sticky/gluey pull and grip enforced by the fear and desire.
Also, the perspectives are maintained by being placed into the back ground (in our subconscious) by other perspectives, in turn. And this makes accessing and digging of perspective layers extremely difficult because we have to go through things we hate, dislike, dear and get annoyed to face things placed in the negatively recognized back ground.
So, even though we may know that our sense and feeling of reality and certainty is telling the key and pass way to the detachment/disillusionment, it won’t happen for most people.
It would take highly motivated person with exceptionally strong attachment to stick on the sense of reality and keep facing it no matter what.
It also takes absolute honesty as far as one’s desire, feeling, and logic are concerned.
But most people aren’t very honest about own desire nor feeling. And only very few people are logical enough to be honest to one’s own logic.
In other words, what I just wrote was pretty damn interesting for me and it’s a very practical kind of information to me, but it may not so for most readers.
But who knows? Someone may find it and use it in practice, too. 
Recap:
The sense of reality, certainty indicates the sticky/gluey quality of the given perspective (with which and/or in which one is feeling the reality, certainty).
By facing and staying with the sense of reality/certainty, the composition of sticky/gluey quality will become clear and then they will loose the grip when its nature )the temporary and limited, conditional nature of any perspective) is evident.
The sticky/gluey quality comes from our fear/desire that make us escape from or run after the matter, and thus create the distance or angle between our awareness and the matter (although always in our illusion).
And the degree of stickiness is often strengthened by things like artificial beliefs (or a sort of hypnotism), music (enhancing emotional perspectives), and thought and words that express certainty and affirmation (with words like “absolute”, “truth”, “fact”, “reality”, and any other concepts/words of overrating, magnifying, and/or glorifying nature).