user13375: Are these two words synonymous? Is everything that exists, real? Is everything real, an existent? What is a proper relationship between the words "real" and "exists" in the context of Buddhist doctrine? What is a proper definition of "real" and of "exists" in the context of Buddhist doctrine?
Are dreams real? Do they exist? Are illusions real? Do they exist? Are chairs real? Do they exist? Are persons real? Do they exist? Is the son of a barren woman real? Do they exist? Is there anything that is real, but does not exist?
What do we really mean when we say something is real? Pun intended.

user471: The Pali suttas are almost the same as Mahayana agamas in Sanskrit, and so would be on-topic as Mahayana-relevant content.
From DN 17:

See, Ānanda! All those conditioned phenomena have passed, ceased, and
perished. So impermanent are conditions, so unstable are conditions,
so unreliable are conditions. This is quite enough for you to become
disillusioned, dispassionate, and freed regarding all conditions.

The Buddha was not concerned whether a chair is real or not. He only noted all such conditioned and compounded things as impermanent, unstable and unreliable.
If by "unreal", you mean that a chair is impermanent, unstable, unreliable, conditioned and compounded, then we can say that the chair is unreal.
However, if by "unreal" you mean the chair doesn't exist, then it's not acceptable, because according to MN 1 below, a Buddha (who is fully enlightened and fully understood it to the end) sees earth as earth, water as water, fire as fire etc. He sees things as they are. In other words, they exist, even if only for one moment.
From MN 1:

“Bhikkhus, the Tathāgata, too, accomplished and fully enlightened,
directly knows earth as earth. Having directly known earth as earth,
he does not conceive himself as earth, he does not conceive himself in
earth, he does not conceive himself apart from earth, he does not
conceive earth to be ‘mine,’ he does not delight in earth. Why is
that? Because the Tathāgata has fully understood it to the end, I say.
“He too directly knows water as water ... Why is that?
Because the Tathāgata has fully understood it to the end, I say.


user-1: A way to think about this is that in the context of the doctrine of self then the Buddha is real but we won't be able to pin down the Buddha as a truth or reality and it is therefore a false doctrine precisely because we can't pin a Buddha down as a truth or reality.

What do you think, Anuradha: Is form constant or inconstant?"
"Inconstant, lord."
"And is that which is inconstant easeful or stressful?"
"Stressful, lord."
"And is it proper to regard what is inconstant, stressful, subject to change as: 'This is mine. This is my self. This is what I am'?"
"No, lord."
"Is feeling constant or inconstant?"
"Inconstant, lord."...
"Is perception constant or inconstant?"
"Inconstant, lord."...
"Are fabrications constant or inconstant?"
"Inconstant, lord."...
"Is consciousness constant or inconstant?
"Inconstant, lord."
"And is that which is inconstant easeful or stressful?"
"Stressful, lord."
"And is it proper to regard what is inconstant, stressful, subject to change as: 'This is mine. This is my self. This is what I am'?"
"No, lord."
"What do you think, Anuradha: Do you regard form as the Tathagata?"
"No, lord."
"Do you regard feeling as the Tathagata?"
"No, lord."
"Do you regard perception as the Tathagata?"
"No, lord."
"Do you regard fabrications as the Tathagata?"
"No, lord."
"Do you regard consciousness as the Tathagata?"
"No, lord."
"What do you think, Anuradha: Do you regard the Tathagata as being in form?... Elsewhere than form?... In feeling?... Elsewhere than feeling?... In perception?... Elsewhere than perception?... In fabrications?... Elsewhere than fabrications?... In consciousness?... Elsewhere than consciousness?"
"No, lord."
"What do you think: Do you regard the Tathagata as form-feeling-perception-fabrications-consciousness?"
"No, lord."
"Do you regard the Tathagata as that which is without form, without feeling, without perception, without fabrications, without consciousness?"
"No, lord."
"And so, Anuradha — when you can't pin down the Tathagata as a truth or reality even in the present life — is it proper for you to declare, 'Friends, the Tathagata — the supreme man, the superlative man, attainer of the superlative attainment — being described, is described otherwise than with these four positions: The Tathagata exists after death, does not exist after death, both does & does not exist after death, neither exists nor does not exist after death'?"
"No, lord."
"Very good, Anuradha. Very good. Both formerly & now, it is only stress that I describe, and the cessation of stress."

This is opposed to the truth & reality of the inferable elements which are experimentally verifiable.
Eg

we know that eye is by itself not seeing but there is no seeing without an eye
we know that visible medium is by itself not seeing but there is no seeing without the seen (ie a person can not see if there is no light.
we know that consciousness is not seeing but there is no seeing without consciousness, an unconscious person doesn't see even if you shine light in that eye

Only when there is a meeting of the eye, that which is visible to the eye and eye consciousness is there seeing, therefore contact is real and pinned as a true statement about that which we are thinking about.

Bhikkhus, there are these four kinds of clinging. What four? Clinging to sensual pleasures, clinging to views, clinging to rules and observances, and clinging to a doctrine of self.

One who clings to this doctrine comes to ask questions like does the Buddha exist after death and etc

user20855: In the conventional truth, mirages exist and are real as a mirage but not real as water. Dreams exist and are real as dream but not as a play in a theater.
So there is nothing which can be said conventionally existing but unreal because it is real in that way it is called to exist.
Conventionally existent Buddhas alleviate the conventionally existing suffering of conventionally existent sentient beings.
The suffering sentient beings are conventionally existent and are also conventionally real.
Conventionally existent Buddhas however don't alleviate the conventionally unreal and nonexistent suffering of the son of a barren woman.
I think this answer by @Tenzin Dorje to a related question may be relevant too.

user10100: There are 2 objects of knowing...

Reality (yathabhūta) - the existent without imagination.

Imagination (sammati,smaññā) - the conception which appearing only while imagining.


We are knowing both switching rapidly. Trillion times of mind moment in a second, there are many moment knowing realities and many moment imagining  imaginations switching rapidly. We see many realities such as colors, voices, smells, tastes, tempture or hardness or motion, then we imagine "this is piece", "this is loaf", "This many loaf is body", "this body is me", etc.
Reality can be exist without imagination, but imagination never exist and never arise, only concept.

There are 2 realities...

Saṅkhata - causes & their effect which constructing, conditioning each others to arise and to vanish. This is exist only when it arising. See SN. SaṅkhataLakkhaṇaSutta. It is exist only when arising, but it is real in every right recalling.

Asaṅkhata- Nibbāna, the opposite of Saṅkhata.  This is exist forever, but it is neither arising nor vanishing because it is the opposite of Saṅkhata.



Ther are 3 existents...

real existent - Saṅkhata and Asaṅkhata.

right imagined existent - the imagination which imagined by any mind without wrong-view-clinging about the reality which really possible to arise and to vanish (saṅkhāra) or to be (nibbāna).

wrong imagined existent -  the imagination which imagined by wrong-view-clinging about the misunderstood of reality, wrong causes and wrong effects in of trillions times arising in a second moment. For the example, when we are reading this answer, we read it by wholesome, unwholesome, resultant, and neither-wholesome-nor-unwholesome-minds switching rapidly. There also are many
trillions of object pass trough the senses as well. However, we imagine they are only a wholesome mind, only an object, only me, one body from birth, etc. This is imagination.



There are deeply uncountable detail of the truth. This is why the concentration meditation is still important in Tipitaka, although the insight meditation is the way to see the truth. The deeply and variant detail makes the insight meditation hard to control without the concentration meditation for the practitioner who has low skill of 10 perfections (Pāramī).

13375: <p>Are these two words synonymous? Is everything that exists, real? Is everything real, an existent? What is a proper relationship between the words &quot;real&quot; and &quot;exists&quot; in the context of Buddhist doctrine? What is a proper definition of &quot;real&quot; and of &quot;exists&quot; in the context of Buddhist doctrine?</p>
<p>Are dreams real? Do they exist? Are illusions real? Do they exist? Are chairs real? Do they exist? Are persons real? Do they exist? Is the son of a barren woman real? Do they exist? Is there anything that is real, but does not exist?</p>
<p>What do we <em>really</em> mean when we say something is real? Pun intended.</p>
 471: <p>The Pali suttas are almost the same as Mahayana agamas in Sanskrit, and so would be on-topic as Mahayana-relevant content.</p>
<p>From <a href="https://suttacentral.net/dn17/en/sujato" rel="nofollow noreferrer">DN 17</a>:</p>
<blockquote>
<p>See, Ānanda! All those conditioned phenomena have passed, ceased, and
perished. So impermanent are conditions, so unstable are conditions,
so unreliable are conditions. This is quite enough for you to become
disillusioned, dispassionate, and freed regarding all conditions.</p>
</blockquote>
<p>The Buddha was not concerned whether a chair is real or not. He only noted all such conditioned and compounded things as impermanent, unstable and unreliable.</p>
<p>If by &quot;unreal&quot;, you mean that a chair is impermanent, unstable, unreliable, conditioned and compounded, then we can say that the chair is unreal.</p>
<p>However, if by &quot;unreal&quot; you mean the chair doesn't exist, then it's not acceptable, because according to <a href="https://suttacentral.net/mn1/en/bodhi" rel="nofollow noreferrer">MN 1</a> below, a Buddha (who is fully enlightened and fully understood it to the end) sees earth as earth, water as water, fire as fire etc. He sees things as they are. In other words, they exist, even if only for one moment.</p>
<p>From <a href="https://suttacentral.net/mn1/en/bodhi" rel="nofollow noreferrer">MN 1</a>:</p>
<blockquote>
<p>“Bhikkhus, the Tathāgata, too, accomplished and fully enlightened,
directly knows earth as earth. Having directly known earth as earth,
he does not conceive himself as earth, he does not conceive himself in
earth, he does not conceive himself apart from earth, he does not
conceive earth to be ‘mine,’ he does not delight in earth. Why is
that? Because the Tathāgata has fully understood it to the end, I say.</p>
<p>“He too directly knows water as water ... Why is that?
Because the Tathāgata has fully understood it to the end, I say.</p>
</blockquote>
 -1: <p>A way to think about this is that in the context of the doctrine of self then the Buddha is real but we won't be able to pin down the Buddha as a truth or reality and it is therefore a false doctrine precisely because we can't pin a Buddha down as a truth or reality.</p>
<blockquote>
<p>What do you think, Anuradha: Is form constant or inconstant?&quot;</p>
<p>&quot;Inconstant, lord.&quot;</p>
<p>&quot;And is that which is inconstant easeful or stressful?&quot;</p>
<p>&quot;Stressful, lord.&quot;</p>
<p>&quot;And is it proper to regard what is inconstant, stressful, subject to change as: 'This is mine. This is my self. This is what I am'?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;Is feeling constant or inconstant?&quot;</p>
<p>&quot;Inconstant, lord.&quot;...</p>
<p>&quot;Is perception constant or inconstant?&quot;</p>
<p>&quot;Inconstant, lord.&quot;...</p>
<p>&quot;Are fabrications constant or inconstant?&quot;</p>
<p>&quot;Inconstant, lord.&quot;...</p>
<p>&quot;Is consciousness constant or inconstant?</p>
<p>&quot;Inconstant, lord.&quot;</p>
<p>&quot;And is that which is inconstant easeful or stressful?&quot;</p>
<p>&quot;Stressful, lord.&quot;</p>
<p>&quot;And is it proper to regard what is inconstant, stressful, subject to change as: 'This is mine. This is my self. This is what I am'?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;What do you think, Anuradha: Do you regard form as the Tathagata?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;Do you regard feeling as the Tathagata?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;Do you regard perception as the Tathagata?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;Do you regard fabrications as the Tathagata?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;Do you regard consciousness as the Tathagata?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;What do you think, Anuradha: Do you regard the Tathagata as being in form?... Elsewhere than form?... In feeling?... Elsewhere than feeling?... In perception?... Elsewhere than perception?... In fabrications?... Elsewhere than fabrications?... In consciousness?... Elsewhere than consciousness?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;What do you think: Do you regard the Tathagata as form-feeling-perception-fabrications-consciousness?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;Do you regard the Tathagata as that which is without form, without feeling, without perception, without fabrications, without consciousness?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;And so, Anuradha — <strong>when you can't pin down the Tathagata as a truth or reality even in the present life</strong> — is it proper for you to declare, 'Friends, the Tathagata — the supreme man, the superlative man, attainer of the superlative attainment — being described, is described otherwise than with these four positions: The Tathagata exists after death, does not exist after death, both does &amp; does not exist after death, neither exists nor does not exist after death'?&quot;</p>
<p>&quot;No, lord.&quot;</p>
<p>&quot;Very good, Anuradha. Very good. Both formerly &amp; now, it is only stress that I describe, and the cessation of stress.&quot;</p>
</blockquote>
<p>This is opposed to the truth &amp; reality of the inferable elements which are experimentally verifiable.</p>
<p>Eg</p>
<ul>
<li>we know that eye is by itself not seeing but there is no seeing without an eye</li>
<li>we know that visible medium is by itself not seeing but there is no seeing without the seen (ie a person can not see if there is no light.</li>
<li>we know that consciousness is not seeing but there is no seeing without consciousness, an unconscious person doesn't see even if you shine light in that eye</li>
</ul>
<p>Only when there is a meeting of the eye, that which is visible to the eye and eye consciousness is there seeing, therefore contact is real and pinned as a true statement about that which we are thinking about.</p>
<blockquote>
<p>Bhikkhus, there are these four kinds of clinging. What four? Clinging to sensual pleasures, clinging to views, clinging to rules and observances, and <strong>clinging to a doctrine of self.</strong></p>
</blockquote>
<p>One who clings to this doctrine comes to ask questions like does the Buddha exist after death and etc</p>
 20855: <p>In the conventional truth, mirages exist and are real as a mirage but not real as water. Dreams exist and are real as dream but not as a play in a theater.</p>
<p>So there is nothing which can be said conventionally existing but unreal because it is real in that way it is called to exist.</p>
<p>Conventionally existent Buddhas alleviate the conventionally existing suffering of conventionally existent sentient beings.</p>
<p>The suffering sentient beings are conventionally existent and are also conventionally real.</p>
<p>Conventionally existent Buddhas however don't alleviate the conventionally unreal and nonexistent suffering of the son of a barren woman.</p>
<p>I think <a href="https://buddhism.stackexchange.com/a/24905">this</a> answer by @Tenzin Dorje to a related question may be relevant too.</p>
 10100: <p>There are 2 objects of knowing...</p>
<ol>
<li><p>Reality (yathabhūta) - the existent without imagination.</p>
</li>
<li><p>Imagination (sammati,smaññā) - the conception which appearing only while imagining.</p>
</li>
</ol>
<p>We are knowing both switching rapidly. Trillion times of mind moment in a second, there are many moment knowing realities and many moment imagining  imaginations switching rapidly. We see many realities such as colors, voices, smells, tastes, tempture or hardness or motion, then we imagine &quot;this is piece&quot;, &quot;this is loaf&quot;, &quot;This many loaf is body&quot;, &quot;this body is me&quot;, etc.</p>
<p>Reality can be exist without imagination, but imagination never exist and never arise, only concept.</p>
<hr />
<p>There are 2 realities...</p>
<ol>
<li><p>Saṅkhata - causes &amp; their effect which constructing, conditioning each others to arise and to vanish. <strong>This is exist only when it arising.</strong> See SN. SaṅkhataLakkhaṇaSutta. It is exist only when arising, but it is real in every right recalling.</p>
</li>
<li><p>Asaṅkhata- Nibbāna, the opposite of Saṅkhata.  <strong>This is exist forever, but it is neither arising nor vanishing because it is the opposite of Saṅkhata.</strong></p>
</li>
</ol>
<hr />
<p>Ther are 3 existents...</p>
<ol>
<li><p>real existent - Saṅkhata and Asaṅkhata.</p>
</li>
<li><p>right imagined existent - the imagination which imagined by any mind without wrong-view-clinging about the reality which really possible to arise and to vanish (saṅkhāra) or to be (nibbāna).</p>
</li>
<li><p>wrong imagined existent -  the imagination which imagined by wrong-view-clinging about the misunderstood of reality, wrong causes and wrong effects in of trillions times arising in a second moment. For the example, when we are reading this answer, we read it by wholesome, unwholesome, resultant, and neither-wholesome-nor-unwholesome-minds switching rapidly. There also are many
trillions of object pass trough the senses as well. However, we imagine they are only a wholesome mind, only an object, only me, one body from birth, etc. <strong>This is imagination.</strong></p>
</li>
</ol>
<hr />
<p>There are deeply uncountable detail of the truth. This is why the concentration meditation is still important in Tipitaka, although the insight meditation is the way to see the truth. The deeply and variant detail makes the insight meditation hard to control without the concentration meditation for the practitioner who has low skill of 10 perfections (Pāramī).</p>
