Reality

[Pondera]

Kasina means “totality”. https://www.philosophy-science-humaniti ... t=Totality

There are exactly ten of them. They exist independently of your observation. Before Buddhaghosa turned the word kasina into a “roundish kind of mixture of brown clay that you stare at until the image of it is burned into your retina - now run to your dorm and make it reappear … etc.” Totality was an unbounded “reality” of which the world was composed (if you care what the Buddha had to say about it).

It is the perception from what the sign appears with the development by apprehending mentally the sign what is apprehended by the eye. (being aware of the eye seeing an object)
And the sign is an appearance, meaning that it is without individual essence albeit exact same with the object, and you know it is mental.

About the "running to your dorm.." thing. The sign here is learning sign and what matters here is that you can make it appear. As the 'making it appear' becomes avail it is called learning sign.
Other words it is not about the object nor its image, it is not retina burn nor mental representation of an object, it is about using the function of the sign appears, it is much more difficult to do without the physical support in a sense it requires fundamental knowhow.

I get every time smarter about Vissudhimagga by reading it, i think it takes time to get used to with the Visuddhimagga terms and it is yet another alchemy book for me.

Path of Purity is great. Don’t get me wrong. I’ve read it cover to cover maybe five times.

I’m just not convinced about the concentration section. And there are easier ways to enter samadhi.

[auto]

There are exactly ten of them. They exist independently of your observation. Before Buddhaghosa turned the word kasina into a “roundish kind of mixture of brown clay that you stare at until the image of it is burned into your retina - now run to your dorm and make it reappear … etc.” Totality was an unbounded “reality” of which the world was composed (if you care what the Buddha had to say about it).

after-image based on vimuttimagga,

THE AFTER-IMAGE
Through the following of that (the grasping sign) again and again the
after-image arises. The after-image means this: what when a man contem-
plates appears together with mind. Here the mind does not gain collectedness
through viewing the mandala, but it (the after-image) can be seen with closed
eyes as before (while looking at the mandala) only in thought. If he wills to
see it far, he sees it afar. As regards seeing it near, to the left, to the right,
before, behind, within, without, above and below, it is the same. It appears
together with mind. This is called the after-image.

if to read the above quote, at least the instruction is easy

I’m just not convinced about the concentration section. And there are easier ways to enter samadhi.

[mjaviem]

What is reality?...

The truth and reality the Buddha awakened to and broke through to is specific conditionality of what is dependently originated.

... Is every experience a mere concept, or not?...

No! Vedanas can be discerned as present and unable to endure.

... Is there a reality behind some concepts and not others, or not?...

No! In every sankhara this inability to last can be discerned.

[samsarayoga]

The mahakalpa is divided into 4 parts. The creation kalpa, the existence kalpa, the destruction kalpa (fire), and the emptiness kalpa. If you read buddhavamsa, it takes Prince Gautama 100k earths to become Buddha.

Also see the 5 skandas:
• 4 elements (it's basically how people in the past view the material world; in solid, liquid, gas and plasma form)
• 5 senses
• instinct
• sentient mind
• consciousness (the soul)

[lostitude]

What is reality? Is every experience a mere concept, or not? Is there a reality behind some concepts and not others, or not? I have my own view, but I’m interested in hearing the position of other members?

Since no one seems to have mentioned the evolutionary perspective: reality is whatever organisms are faced with, and that includes humans. In that sense, wondering if the tree over there is real or not makes no sense, because if you suppose it’s some algorithm fed to you by the Matrix (or some such), well you will never have access to that kind of scenario, it will never manifest itself to you, it will never be... real, so it makes no sense to even entertain it.
As for concepts, they are ways to describe/analyze/categorise reality, they are stuff that you add onto reality, but they are not reality itself.