These points are elucidated here:
Madhyamaka is Not Nihilism, by Jay Garfield: https://jaygarfield.files.wordpress.com ... ilism1.pdf
Taking Conventional Truth Seriously, by Jay Garfield: https://www.jstor.org/stable/40666588?r ... b_contents
The Mulamadyhamakakarika's (Nagarjuna's foundational work) message is "not to say either that emptiness, dependent arising or conventional phenomena are nonexistent — that they are hallucinations. Indeed it is to say the opposite."
-Fundamental Wisdom of the Middle Way, Jay Garfield, p 177
And here are just a few of the many quotes that demonstrate beyond any doubt (and can only be argued against by eel wiggling and redefining words) that the Buddha's teachings are wholly incompatible with the "nothing exists/everything is imaginary" school.Nagarjuna is in fact a robust realist, offering an analysis, not a refutation of existence.
Madhyamaka is Not Nihilism, page 1
Jay L Garfield
Smith College
University of Melbourne
Central University of Tibetan Studies
At Sāvatthī. “Bhikkhus, I do not dispute with the world; rather, it is the world that disputes with me. A proponent of the Dhamma does not dispute with anyone in the world. Of that which the wise in the world agree upon as not existing, I too say that it does not exist. And of that which the wise in the world agree upon as existing, I too say that it exists"
...
“And what is it, bhikkhus, that the wise in the world agree upon as existing, of which I too say that it exists? Form that is impermanent, suffering, and subject to change: this the wise in the world agree upon as existing, and I too say that it exists. Feeling … Perception … Volitional formations … Consciousness that is impermanent, suffering, and subject to change: this the wise in the world agree upon as existing, and I too say that it exists.
“That, bhikkhus, is what the wise in the world agree upon as existing, of which I too say that it exists.
-SN 22.94
Commentary by Bhikkhu Bodhi:
This portion of the sutta offers an important counterpoint to the message of the Kaccānagotta Sutta (12:15). Here the Buddha emphasizes that he does not reject all ontological propositions, but only those that transcend the bounds of possible experience. While the Kaccānagotta Sutta shows that the “middle teaching” excludes static, substantialist conceptions of existence and nonexistence, the present text shows that the same “middle teaching” can accommodate definite pronouncements about these ontological issues. The affirmation of the existence of the five aggregates, as impermanent processes, serves as a rejoinder to illusionist theories, which hold that the world lacks real being.
Feeling, perception, and consciousness are conjoined, friend, not disjoined. It is not possible, having separated them one from another, to delineate the difference among them. For what one feels, that one perceives. What one perceives, that one cognizes. Therefore these qualities are conjoined, not disjoined, and it is not possible, having separated them one from another, to delineate the difference among them."
...
What is the difference between one who is dead, who has completed his time, and a monk who has attained the cessation of perception & feeling?"
"In the case of the one who is dead, who has completed his time, his bodily fabrications [breathing] have ceased & subsided, his verbal fabrications [thoughts] ... his mental fabrications [perceptions & feelings] have ceased & subsided, his vitality is exhausted, his heat subsided, & his faculties are scattered.
But in the case of a monk who has attained the cessation of perception & feeling, his bodily fabrications have ceased & subsided, his verbal fabrications ... his mental fabrications have ceased & subsided, his vitality is not exhausted, his heat has not subsided & his [physical sense organ] faculties are exceptionally clear [clean]. This is the difference between one who is dead, who has completed his time, and a monk who has attained the cessation of perception & feeling.
-MN 43
Here is a wonderful response, from another thread, by the Venerable Dhammanando to the question of what suttas support the Classical Theravada position that matter exists and is not imaginary:"If, friends, internally the eye is intact but no external forms come into its range, and there is no corresponding conscious engagement, then there is no manifestation of the corresponding section of consciousness. If internally the eye is intact and external forms come into its range, but there is no corresponding conscious engagement, then there is no manifestation of the corresponding section of consciousness. But when internally the eye is intact and external forms come into its range and there is the corresponding conscious engagement, then there is the manifestation of the corresponding section of consciousness." "Now there comes a time when the external water element is disturbed. It carries away villages, towns, cities, districts, and countries."
-MN 28
Dhammanando wrote: It can be inferred from the fact that in the blind man simile the assertion of the contrary view is used as a simile for stupidity by the Buddha in MN 99 and Kumārakassapa in DN 23. Had the Buddha or his disciple held esse est percipi to be the case (or some other view along similar lines), then the simile would make no sense.
“Student, suppose there were a man born blind who could not see dark and light forms, who could not see blue, yellow, red, or carmine forms, who could not see what was even and uneven, who could not see the stars or the sun and moon. He might say thus: ‘There are no dark and light forms, and no one who sees dark and light forms; there are no blue, yellow, red, or carmine forms, and no one who sees blue, yellow, red, or carmine forms; there is nothing even and uneven, and no one who sees anything even and uneven; there are no stars and no sun and moon, and no one who sees stars and the sun and moon. I do not know these, I do not see these, therefore these do not exist.’ Speaking thus, student, would he be speaking rightly?”
“No, Master Gotama. There are dark and light forms, and those who see dark and light forms…there are the stars and the sun and moon, and those who see the stars and the sun and moon. Saying, ‘I do not know these, I do not see these, therefore these do not exist,’ he would not be speaking rightly.”
“So too, student, the brahmin Pokkharasāti is blind and visionless.
(Subhasutta, MN 99)
Here are some other relevant suttas:
MN 28
SN 35.33
SN 12.2
MN 99 DN 23
DN 15
SN 22.94
SN 12.15
DN 1 + MN 43
Finally, I've seen where crypto-Madhyamaka-Yogacarins argue that even the Abhidhamma taught that all is non-existent or imaginary, well, that also is false, as this can be found therein, where it is taught, quite clearly:
And of course, the Katthavatthu of the Abhidhamma presents conclusive arguments to defeat these interpretations of the suttas. See Kv 9.3, where the idea that matter is subjective is defeated, Kv 7.7 where it is demonstrated that the Earth is not the result of kamma, Kv 22.8, where it is explained that mountains and oceans, and the external world in general are not momentary objects that coincide with consciousness, among others.“All form is that which is...
void of idea,
neither feeling, nor perception, nor synthesis,
disconnected with thought,”
“form exists which is not due to karma having been wrought”
-Ds 2.2.3
So, it becomes quite clear that the idea that the suttas teach that nothing exists or that all is imaginary is entirely false.