user471: According to this comment:

"Form is like a lump of foam ... And consciousness like an illusion" (SN 22.95)
  means something more subtle and interesting, much more deep than just
  "empty of self". It means that these things are "virtual" (in the
  original sense of the word) - they emerge from interaction and only
  exist as interaction, they only seem solid "from inside" but in
  actuality they are like sleight of hand.

I guess this comes from one of the Mahayana schools' interpretation of Madhyamaka shunyata (emptiness).
What does this really mean?
Let's say I have a piece of apple in my hand. I see that it's an apple. I feel that it's an apple when I touch it. I can smell it as an apple. It also tastes like an apple when I bite into it.
How does the apple emerge only from interaction?
How does the apple exist only as interaction?
How is the apple like a sleight of hand that only appears solid, although it's virtual?
I originally thought this is related to physics, where things that we can experience are made of atoms which are mostly empty space. However, Buddhism is almost always related to the mind. So, how does this apply to the mind?
Does this interpretation come from Yogachara?

user7628: 
What does this really mean?

Before enlightenment, the world is seen through the illusion of duality. It is believed that you (a human being) exists and is interacting with a multitude of objects that exist separate from yourself. This belief system has been historically given the label materialism. In this belief system, what is real is the atoms and physical matter that exists in the material world, and your mind (5 senses and thought) are side effects, created by the complex system that exists as your physical body.
Based on your questions, it seems as if you still believe this is the case. Before I answer your questions, it is easier to understand what I am saying if you reflect on your own experience first.
It is important to first pause to consider if you have ever experienced anything "physical" in your entire life. Seeing, hearing, tasting, touching, smelling, and thinking are all immaterial sensations that can not be given to another nor placed in a box. Have you ever experienced anything other than these sensations? If no, what proof can you find that something physical does exist? Is it possible to find proof?
Now, on to your questions.

Let's say I have a piece of apple in my hand. I see that it's an apple. I feel that it's an apple when I touch it. I can smell it as an apple. It also tastes like an apple when I bite into it.

Look over these sentences again. You are describing sight, touch, smell, and taste. You are not describing an apple. What you call an apple, is simply a label you place on a subsection of your sight, touch, smell, and taste. You are saying "this sight I identify as an apple, this touch I identify as an apple, etc."
What is happening is you are breaking down and dividing these sensations into multiple different concepts. When you are observing sight, you are only ever seeing one thing, sight itself. But then, we take sight as a whole and break it down into multiple subsections and concepts. What once was sight is now your hand, the apple, and the room around you. This process of breaking apart a single thing and classifying it as multiple is one way the illusion around you persists. You see your hand and the apple as two different things, but that is not true. At first you may think both your hand and the apple exist within sight, but both are simply the same sight you have broken apart into different ideas. Sight is what is real and exists, and you have imagined your sight to be objects, instead of simply sight.

How does the apple emerge only from interaction?
How does the apple exist only as interaction?

Interaction is only possible to occur if duality exists. You believe you are one thing. You believe the apple is another, separate from you. Believing both of these things is what makes interaction seemingly possible.
If there is no you, and there is no apple, can interaction occur? If there is simply sight appearing, is any interaction taking place?
By holding the false belief that you are "this" and not "that", you instantaneously create the belief in both your and the apple's existence. If you did not believe you were separate from the apple, would the apple still exist? Or would it simply be a part of you?

How is the apple like a sleight of hand that only appears solid, although it's virtual?

Now that Virtual reality technology is accessible to the masses, lets have a VR example.
Image you put on a virtual reality headset and turn it on. Immediately you find yourself standing in front of a table. On the table sits an apple.
Imagine you bend down and inspect the apple from multiple angles. You see the light shimmering off, and it looks tasty. Imagine you are wearing gloves that allow you to pick up the apple. You reach down and grab the apple and lift it off the table and toss it across the room.
Does the apple you see in your headset physically exist? Is there physical matter there making up the apple you are holding? No. In VR, you are simply looking at a screen, and although you are seeing and interacting with many things that seem real, its really just images on a screen. Although the VR apple appears solid, it is not. Its virtual.
There is no difference between that example, and the sight you experience every day. Just because you see, taste, and smell an apple in your fridge, does not mean there is a physical entity that exists outside of the realm of your senses. The illusion of "physical" reality is brought about by our religious devotion to the idea that something exists other than the contents of our minds. Even though we never have, nor never will experience anything other than the 5 senses and thought, people are still trapped by the belief that there is something else out there.

I originally thought this is related to physics, where things that we can experience are made of atoms which are mostly empty space. However, Buddhism is almost always related to the mind. So, how does this apply to the mind?

Physics is a useful conceptual framework for accomplishing a task. Just because it is useful for something, does not mean it reflects the nature of reality or even exists. Many amazing things have come about due to an understanding of this very deep and amazing conceptual framework that has been developed. Although it is useful, does that mean it is accurate in describing our universe?
It can be a hard pill to swallow that all of physics may not describe anything real, so lets give a smaller example that is more manageable, but the concept still applies to all of physics. Think about the number two. Mathematics wouldn't be the same without two. Think of all the amazing uses we have for two. Although the number two is extremely useful, does two even exist in reality? Can you find a two and save it for later? Does it describe anything real? Or is it simply a concept we have constructed as a useful tool?
When exploring reality, it is important to be meticulous and question everything you believe to be true. Even something everyone in America is taught to be "true" like physics should be scrutinized. All you have ever experienced is the mind. On what basis do you believe something exists other than the mind? Beginning to follow this movement inward is paramount to understanding and experiencing the freedom that is enlightenment.
I hope what I wrote will be helpful to you in some way. I pray for nothing more than your liberation this lifetime.

user254: It's an axiom of Physics that you can "observe" something only by "interacting" with it -- for example, by bouncing a photon off of it, to see it.
Also what you observe depends on the type of interaction -- if you observe something using the "fire a bullet at it" method, then perhaps using that method you couldn't tell the difference between an apple and a potato.
Hominids (and other primates) can distinguish "red", incidentally -- that type of colour vision is rare among mammals, and perhaps it exists because primates uniquely evolved to climb trees and to recognise by sight which fruits are ripe -- a human might (literally as well as figuratively) see an apple as food in a way that e.g. a cat would not.
An apple appears to be "solid" until or unless you bite it. You have learned how to handle an apple carefully (so as not to damage it).
To me the comment about "interaction" implied:

It depends on "learning" -- you learn how to recognise an apple, how to use an apple, how to preserve an apple, how to name an apple, how to classify apples, how to compare current experiences with previous "apple-related" experiences
You learn a limited set of appropriate interactions with apples -- e.g. "hold it in your hand and feel it", "sniff it", etc. -- those interactions elicit the familiar apple-like properties
You learn to use your test apparatus -- i.e. your senses -- e.g. (perhaps as a child) you learn how different things feel when you pick them up and handle them
And of course you learned how to name as well as recognise apples (e.g. when you learned your "first language")

More literally than learning how "things" feel, you learn the "feelings" or sensations you experience -- e.g. learn to associate the "feeling of hefting 'an apple'" with the "sight of what 'an apple' looks like". It's the interaction of several senses (and memory) that leads to you declare that something should be named "an apple" -- not to be confused with e.g. "a picture of an apple", "apple juice", "a rotten apple", "a apple made of wax or plastic", "an apple seed", "a whole wagon-load of apples", "an apple tree", etc.
I'm not sure I understand what sankhara and nama-rupa mean in the context of the 12 nidanas, but perhaps this is related to that.

user43: It was said:

Form [is void, hollow, insubstantial] like a lump of foam,
  Feeling like a water bubble;
  Perception is like a mirage,
  Volitions like a plantain trunk,
  And consciousness like an illusion,
  So explained the Kinsman of the Sun  

And then it was said 

[the above] means something more subtle and interesting, much more deep than just "empty of self". It means that these things are "virtual" (in the original sense of the word) - they emerge from interaction and only exist as interaction, they only seem solid "from inside" but in actuality they are like sleight of hand.

This was said in reference to subjective phenomena like feeling, perception - up to and including the overall subjective experience (consciousness) itself. They are "virtual" (=seeming), in the sense that they only exist "inside the subjective space". If you look at a human being from the outside, you can measure its brain activities, the neurons firing etc. - and based on that you can guess what they experience, but the actual features of their subjective experience only exist virtually, as mind-phenomena. And there they are very solid. A pain from a cut finger is a very solid and concrete experience, even though from the outside it is only a tiny change in some neurons' firing rate.
Now, this makes sense about feeling etc. but what about form (rupa), how is that virtual. This piece is usually explained in Mahayana folklore on examples of various non-human beings, either real or imaginary.
For example, we could say, imagine subjective experience of a worm born from an egg attached to the skin of apple. Does their experience involve what we call apple? Clearly, experience of a worm is nothing like ours. For a newborn worm the apple is its entire universe, and as they grow up they may or may not reach a point where they realize that the apple has boundaries and is round. So for the worm the rupa (form) of apple is nowhere to be found. They deal with entirely different scale of things on which the rupas are different. So the form, just like other phenomena, emerges from interaction.
Now, this is not to say that the Buddhism of Mahayana subscribes to some kind of Subjective Idealism. This just means that (per Mahayana), our ideas of objects, entities, properties, qualities, events, boundaries, interactions etc. - are deeply rooted in incorrect (anthropocentric, egocentric, americentric etc) assumptions about these things (objects, entities, properties, qualities, events, interactions) being actually 
(ontologically) the same as what they appear to us in our subjective experience. 
When this particular realization is made and is practiced in daily life, our habits of seeing the world start changing - and slowly we go from naive materialistic superficial what Buddhists call "tainted" vision to what's called the enlightened vision, which is to say, a vision that involves seeing beyond the superficial appearances, and beyond our singlesided anthropocentric and egocentric perspectives.
The reason Mahayana says this entire line of thinking is connected with the Buddhist quest to end suffering, is because, according to Mahayana, suffering (and its causes of craving, aversion, and conflict) come from attachment to appearances that arise in our tainted vision, and from assuming that these appearances are solid.
So, to understand "emptiness" of phenomena emerging in tainted vision and to go beyond its limits in our own daily life, is a crucial step towards Enlightenment and Liberation, according to Mahayana.

user-1: Sorta.  Before we get into the meat of things here, remember that Yogacara (which is where that argument grows out of) is first and foremost concerned with liberation, karmic obstacles, and the like.  It doesn't seek to establish some ontological theory regarding the nature of "things out there".  It is a practice methodology, nothing more.    
But about your apple.  Seen from the the perspective of the Yogacara school, it starts to make a whole lot more sense (though it becomes way less mysterious).  Yogacara posits eight consciousnesses.  The first six are sense-based.  If you don't have your six senses engaging the world, you can't have those six consciousness.  No consciousness, no world.  In order for that apple ever to register, it has to impact something's consciousness.  If there is no subject, there can be no object.  
Unlike the schools that precede them, the Yogacara peeps weren't happy with a six sense based model.  Wouldn't, they surmised, the loss of consciousness ultimately lead to instantaneous enlightenment?  Why don't we awaken when someone hits us in the head with a baseball bat?  Wouldn't we become Buddha's if we stopped seeing apples?  More interestingly, how can there be enlightenment when consciousness is still conditioned by sense perception? To answer these questions (which are actually not insignificant) they posited the existence of two more consciousness.  The second, I think, everyone knows at least something about.  That would be the storehouse consciousness.  This is what contains all of our habitual patterning, reactions, memories, etc.  Storehouse consciousness is the reason you hate apples because the kids down the block used to pelt you with them your way home from school.  The other consciousness they identified was the consciousness of identity view; this is the consciousness that groups the other seven into a consistent sense of self.  
So, a concrete example.  You pick up an apple.  You feel it's weight, see its red color, smell the phenolic compounds from where the stem broke off.  You think you haven't had lunch, so you bite into it and taste it.  You immediately remember that you like apples and really should eat them more often.  Notice that every statement is from your perspective.  This whole picture is the Yogacara model of reality.  And it's that pesky you in there - how it ultimately binds together the whole interaction and makes it about some seemingly independent actor - that they were most concerned about.  The question of if that apple exists until you pick it up is only important if it's an obstacle to you overcoming that youview.  Whether that tree falling in the woods makes any sound with no one around to hear is only important if that falling tree is keeping you bound to you. 
(Side note, the falling tree is an example of how koans can work in the context of the alaya.  This koan could be used to "point at" some part of our storehouse consciousness that we might take to be automatic and inevitable but is really originating in our minds and is under our power to disrupt.)

user10767: You only really know of the apples existence by touching it, smelling it and tasting it.  That is, interacting with it. Even looking at it is an interaction.

471: <p>According to <a href="https://buddhism.stackexchange.com/q/33822/471#comment57270_33829">this comment</a>:</p>

<blockquote>
  <p>"Form is like a lump of foam ... And consciousness like an illusion" (<a href="https://suttacentral.net/sn22.95/en/bodhi" rel="nofollow noreferrer">SN 22.95</a>)
  means something more subtle and interesting, much more deep than just
  "empty of self". It means that these things are "virtual" (in the
  original sense of the word) - they emerge from interaction and only
  exist as interaction, they only seem solid "from inside" but in
  actuality they are like sleight of hand.</p>
</blockquote>

<p>I guess this comes from one of the Mahayana schools' interpretation of Madhyamaka shunyata (emptiness).</p>

<p>What does this really mean?</p>

<p>Let's say I have a piece of apple in my hand. I see that it's an apple. I feel that it's an apple when I touch it. I can smell it as an apple. It also tastes like an apple when I bite into it.</p>

<p>How does the apple emerge only from interaction?</p>

<p>How does the apple exist only as interaction?</p>

<p>How is the apple like a sleight of hand that only appears solid, although it's virtual?</p>

<p>I originally thought this is related to physics, where things that we can experience are made of atoms which are mostly empty space. However, Buddhism is almost always related to the mind. So, how does this apply to the mind?</p>

<p>Does this interpretation come from Yogachara?</p>
 7628: <blockquote>
  <p>What does this really mean?</p>
</blockquote>

<p>Before enlightenment, the world is seen through the illusion of duality. It is believed that you (a human being) exists and is interacting with a multitude of objects that exist separate from yourself. This belief system has been historically given the label materialism. In this belief system, what is real is the atoms and physical matter that exists in the material world, and your mind (5 senses and thought) are side effects, created by the complex system that exists as your physical body.</p>

<p>Based on your questions, it seems as if you still believe this is the case. Before I answer your questions, it is easier to understand what I am saying if you reflect on your own experience first.</p>

<p>It is important to first pause to consider if you have ever experienced anything "physical" in your entire life. Seeing, hearing, tasting, touching, smelling, and thinking are all immaterial sensations that can not be given to another nor placed in a box. Have you ever experienced anything other than these sensations? If no, what proof can you find that something physical does exist? Is it possible to find proof?</p>

<p>Now, on to your questions.</p>

<blockquote>
  <p>Let's say I have a piece of apple in my hand. I see that it's an apple. I feel that it's an apple when I touch it. I can smell it as an apple. It also tastes like an apple when I bite into it.</p>
</blockquote>

<p>Look over these sentences again. You are describing sight, touch, smell, and taste. You are not describing an apple. What you call an apple, is simply a label you place on a subsection of your sight, touch, smell, and taste. You are saying "this sight I identify as an apple, this touch I identify as an apple, etc."</p>

<p>What is happening is you are breaking down and dividing these sensations into multiple different concepts. When you are observing sight, you are only ever seeing one thing, sight itself. But then, we take sight as a whole and break it down into multiple subsections and concepts. What once was sight is now your hand, the apple, and the room around you. This process of breaking apart a single thing and classifying it as multiple is one way the illusion around you persists. You see your hand and the apple as two different things, but that is not true. At first you may think both your hand and the apple exist within sight, but both are simply the same sight you have broken apart into different ideas. Sight is what is real and exists, and you have imagined your sight to be objects, instead of simply sight.</p>

<blockquote>
  <p>How does the apple emerge only from interaction?</p>
  
  <p>How does the apple exist only as interaction?</p>
</blockquote>

<p>Interaction is only possible to occur if duality exists. You believe you are one thing. You believe the apple is another, separate from you. Believing both of these things is what makes interaction seemingly possible.</p>

<p>If there is no you, and there is no apple, can interaction occur? If there is simply sight appearing, is any interaction taking place?</p>

<p>By holding the false belief that you are "this" and not "that", you instantaneously create the belief in both your and the apple's existence. If you did not believe you were separate from the apple, would the apple still exist? Or would it simply be a part of you?</p>

<blockquote>
  <p>How is the apple like a sleight of hand that only appears solid, although it's virtual?</p>
</blockquote>

<p>Now that Virtual reality technology is accessible to the masses, lets have a VR example.</p>

<p>Image you put on a virtual reality headset and turn it on. Immediately you find yourself standing in front of a table. On the table sits an apple.</p>

<p>Imagine you bend down and inspect the apple from multiple angles. You see the light shimmering off, and it looks tasty. Imagine you are wearing gloves that allow you to pick up the apple. You reach down and grab the apple and lift it off the table and toss it across the room.</p>

<p>Does the apple you see in your headset physically exist? Is there physical matter there making up the apple you are holding? No. In VR, you are simply looking at a screen, and although you are seeing and interacting with many things that seem real, its really just images on a screen. Although the VR apple appears solid, it is not. Its virtual.</p>

<p>There is no difference between that example, and the sight you experience every day. Just because you see, taste, and smell an apple in your fridge, does not mean there is a physical entity that exists outside of the realm of your senses. The illusion of "physical" reality is brought about by our religious devotion to the idea that something exists other than the contents of our minds. Even though we never have, nor never will experience anything other than the 5 senses and thought, people are still trapped by the belief that there is something else out there.</p>

<blockquote>
  <p>I originally thought this is related to physics, where things that we can experience are made of atoms which are mostly empty space. However, Buddhism is almost always related to the mind. So, how does this apply to the mind?</p>
</blockquote>

<p>Physics is a useful conceptual framework for accomplishing a task. Just because it is useful for something, does not mean it reflects the nature of reality or even exists. Many amazing things have come about due to an understanding of this very deep and amazing conceptual framework that has been developed. Although it is useful, does that mean it is accurate in describing our universe?</p>

<p>It can be a hard pill to swallow that all of physics may not describe anything real, so lets give a smaller example that is more manageable, but the concept still applies to all of physics. Think about the number two. Mathematics wouldn't be the same without two. Think of all the amazing uses we have for two. Although the number two is extremely useful, does two even exist in reality? Can you find a two and save it for later? Does it describe anything real? Or is it simply a concept we have constructed as a useful tool?</p>

<p>When exploring reality, it is important to be meticulous and question everything you believe to be true. Even something everyone in America is taught to be "true" like physics should be scrutinized. All you have ever experienced is the mind. On what basis do you believe something exists other than the mind? Beginning to follow this movement inward is paramount to understanding and experiencing the freedom that is enlightenment.</p>

<p>I hope what I wrote will be helpful to you in some way. I pray for nothing more than your liberation this lifetime.</p>
 254: <p>It's an axiom of Physics that you can "observe" something only by "interacting" with it -- for example, by bouncing a photon off of it, to see it.</p>

<p>Also what you observe depends on the type of interaction -- if you observe something using the "fire a bullet at it" method, then perhaps using that method you couldn't tell the difference between an apple and a potato.</p>

<p>Hominids (and other primates) can distinguish "red", incidentally -- that type of colour vision is rare among mammals, and perhaps it exists because primates uniquely evolved to climb trees and to recognise by sight which fruits are ripe -- a human might (literally as well as figuratively) see an apple as food in a way that e.g. a cat would not.</p>

<p>An apple appears to be "solid" until or unless you bite it. You have learned how to handle an apple carefully (so as not to damage it).</p>

<p>To me the comment about "interaction" implied:</p>

<ul>
<li>It depends on "learning" -- you learn how to recognise an apple, how to use an apple, how to preserve an apple, how to name an apple, how to classify apples, how to compare current experiences with previous "apple-related" experiences</li>
<li>You learn a limited set of appropriate interactions with apples -- e.g. "hold it in your hand and feel it", "sniff it", etc. -- those interactions elicit the familiar apple-like properties</li>
<li>You learn to use your test apparatus -- i.e. your senses -- e.g. (perhaps as a child) you learn how different things feel when you pick them up and handle them</li>
<li>And of course you learned how to name as well as recognise apples (e.g. when you learned your "first language")</li>
</ul>

<p>More literally than learning how "things" feel, you learn the "feelings" or sensations you experience -- e.g. learn to associate the "feeling of hefting 'an apple'" with the "sight of what 'an apple' looks like". It's the interaction of several senses (and memory) that leads to you declare that something should be named "an apple" -- not to be confused with e.g. "a picture of an apple", "apple juice", "a rotten apple", "a apple made of wax or plastic", "an apple seed", "a whole wagon-load of apples", "an apple tree", etc.</p>

<p>I'm not sure I understand what <em>sankhara</em> and <em>nama-rupa</em> mean in the context of the 12 nidanas, but perhaps this is related to that.</p>
 43: <p>It was said:</p>

<blockquote>
  <p>Form [is void, hollow, insubstantial] like a lump of foam,<br>
  Feeling like a water bubble;<br>
  Perception is like a mirage,<br>
  Volitions like a plantain trunk,<br>
  And consciousness like an illusion,<br>
  So explained the Kinsman of the Sun  </p>
</blockquote>

<p>And then it was said </p>

<blockquote>
  <p>[the above] means something more subtle and interesting, much more deep than just "empty of self". It means that these things are "virtual" (in the original sense of the word) - they emerge from interaction and only exist as interaction, they only seem solid "from inside" but in actuality they are like sleight of hand.</p>
</blockquote>

<p>This was said in reference to subjective phenomena like feeling, perception - up to and including the overall subjective experience (consciousness) itself. They are "virtual" (=seeming), in the sense that they only exist "inside the subjective space". If you look at a human being from the outside, you can measure its brain activities, the neurons firing etc. - and based on that you can guess what they experience, but the actual features of their subjective experience only exist virtually, as mind-phenomena. And there they are very solid. A pain from a cut finger is a very solid and concrete experience, even though from the outside it is only a tiny change in some neurons' firing rate.</p>

<p>Now, this makes sense about feeling etc. but what about form (rupa), how is that virtual. This piece is usually explained in Mahayana folklore on examples of various non-human beings, either real or imaginary.</p>

<p>For example, we could say, imagine subjective experience of a worm born from an egg attached to the skin of apple. Does their experience involve what we call apple? Clearly, experience of a worm is nothing like ours. For a newborn worm the apple is its entire universe, and as they grow up they may or may not reach a point where they realize that the apple has boundaries and is round. So for the worm the rupa (form) of apple is nowhere to be found. They deal with entirely different scale of things on which the rupas are different. So the form, just like other phenomena, emerges from interaction.</p>

<p>Now, this is not to say that the Buddhism of Mahayana subscribes to some kind of Subjective Idealism. This just means that (per Mahayana), our ideas of objects, entities, properties, qualities, events, boundaries, interactions etc. - are deeply rooted in incorrect (anthropocentric, egocentric, americentric etc) assumptions about these things (objects, entities, properties, qualities, events, interactions) being actually 
(ontologically) the same as what they appear to us in our subjective experience. </p>

<p>When this particular realization is made and is practiced in daily life, our habits of seeing the world start changing - and slowly we go from naive materialistic superficial what Buddhists call "tainted" vision to what's called the enlightened vision, which is to say, a vision that involves seeing beyond the superficial appearances, and beyond our singlesided anthropocentric and egocentric perspectives.</p>

<p>The reason Mahayana says this entire line of thinking is connected with the Buddhist quest to end suffering, is because, according to Mahayana, suffering (and its causes of craving, aversion, and conflict) come from attachment to appearances that arise in our tainted vision, and from assuming that these appearances are solid.</p>

<p>So, to understand "emptiness" of phenomena emerging in tainted vision and to go beyond its limits in our own daily life, is a crucial step towards Enlightenment and Liberation, according to Mahayana.</p>
 -1: <p>Sorta.  Before we get into the meat of things here, remember that Yogacara (which is where that argument grows out of) is first and foremost concerned with liberation, karmic obstacles, and the like.  It doesn't seek to establish some ontological theory regarding the nature of "things out there".  It is a practice methodology, nothing more.    </p>

<p>But about your apple.  Seen from the the perspective of the Yogacara school, it starts to make a whole lot more sense (though it becomes way less mysterious).  Yogacara posits eight consciousnesses.  The first six are sense-based.  If you don't have your six senses engaging the world, you can't have those six consciousness.  No consciousness, no world.  In order for that apple ever to register, it has to impact some<em>thing's</em> consciousness.  If there is no subject, there can be no object.  </p>

<p>Unlike the schools that precede them, the Yogacara peeps weren't happy with a six sense based model.  Wouldn't, they surmised, the loss of consciousness ultimately lead to instantaneous enlightenment?  Why don't we awaken when someone hits us in the head with a baseball bat?  Wouldn't we become Buddha's if we stopped seeing apples?  More interestingly, how can there be enlightenment when consciousness is still conditioned by sense perception? To answer these questions (which are actually not insignificant) they posited the existence of two more consciousness.  The second, I think, everyone knows at least something about.  That would be the storehouse consciousness.  This is what contains all of our habitual patterning, reactions, memories, etc.  Storehouse consciousness is the reason you hate apples because the kids down the block used to pelt you with them your way home from school.  The other consciousness they identified was the consciousness of identity view; this is the consciousness that groups the other seven into a consistent sense of self.  </p>

<p>So, a concrete example.  You pick up an apple.  You feel it's weight, see its red color, smell the phenolic compounds from where the stem broke off.  You think you haven't had lunch, so you bite into it and taste it.  You immediately remember that you like apples and really should eat them more often.  Notice that every statement is from <em>your</em> perspective.  This whole picture is the Yogacara model of reality.  And it's that pesky <em>you</em> in there - how it ultimately binds together the whole interaction and makes it about some seemingly independent actor - that they were most concerned about.  The question of if that apple exists until you pick it up is only important if it's an obstacle to you overcoming that <em>you</em>view.  Whether that tree falling in the woods makes any sound with no one around to hear is only important if that falling tree is keeping you bound to <em>you</em>. </p>

<p>(Side note, the falling tree is an example of how koans can work in the context of the alaya.  This koan could be used to "point at" some part of our storehouse consciousness that we might take to be automatic and inevitable but is really originating in our minds and is under our power to disrupt.)</p>
 10767: <p>You only really know of the apples existence by touching it, smelling it and tasting it.  That is, interacting with it. Even looking at it is an interaction.</p>
