user-1: In A history of Indian Buddhism: From Sakyamuni to Early Mahayana, Professor Hirakawa states:

Both nirvana and space were considered to be unconditioned dharmas. This fundamental classification of dharmas into conditioned and unconditioned is found in the Agamas.

In what passage from the agamas (and/or pali?) we read space to be unconditioned?

user2282: Space is one of the 24 kinds of derived-materiality (UpadayaRupa), which is one of the 2 kinds of materiality (the other is primary-materiality, BhutaRupa, which is composed of the 4 elements of earth, water, fire, and air). They're all conditioned dhammas. Only Nibbana is the unconditioned one. Further info. is available at Vism.XIV.34

user-1: @Unrul3r is correct. Because the aforementioned book is almost devoid of notes, only much later an explanation appeared. It's abhidhamma material, the context of the sentence confused me.

In the Sarvāstivādin tradition since the compilation of the Dharmaskhanda, three unconditioned dharmas have been recognized: analytical cessation (pratisankhayā-nirodha), nonanalytical cessation (apratisankhayā-nirodha) and space (ākāśa). In the Theravada tradition, only one unconditioned dharma, nirvana, is recognized [...]. According to the Samaya, the Mahāsanghika, Ekavyavahārika, Lokottaravādin, and Kaukutica schools all recognized the following nine unconditioned dharmas: (1) analytical cessation (2) nonanalytical cessation (3) space (4) the realm of infinity of space (5) the realm of infinity of consciousness (6) the realm of nothingness (7) the realm of neither consciousness nor unconsciousness (8) the law of dependent origination (9) the law of the noble path [...]. The Sarvāstivādins disagreed with this position and did not recognize the existence of a principle of Dependend Origination separate from conditioned dharmas. For the Sarvāstivādins, the law of Dependend Origination itself was conditioned.
For the Mahaśiśākas, the path to nirvana was recognized as an unconditioned dharma because the practices established by the Buddha were considered to be eternal truths. The Sarvāstivādins opposed this position by maintaining that although nirvana was unconditioned, the wisdom the Buddha had realized was conditioned and not eternal.


-1: <p>In <em>A history of Indian Buddhism: From Sakyamuni to Early Mahayana</em>, Professor Hirakawa states:</p>

<blockquote>
  <p>Both nirvana and space were considered to be unconditioned dharmas. This fundamental classification of dharmas into conditioned and unconditioned is found in the Agamas.</p>
</blockquote>

<p>In what passage from the agamas (and/or pali?) we read <em>space</em> to be unconditioned?</p>
 2282: <p>Space is one of the 24 kinds of derived-materiality (UpadayaRupa), which is one of the 2 kinds of materiality (the other is primary-materiality, BhutaRupa, which is composed of the 4 elements of earth, water, fire, and air). They're all conditioned dhammas. Only Nibbana is the unconditioned one. Further info. is available at <a href="http://www.accesstoinsight.org/lib/authors/nanamoli/PathofPurification2011.pdf">Vism.XIV.34</a></p>
 -1: <p>@Unrul3r is correct. Because the aforementioned book is almost devoid of notes, only much later an explanation appeared. It's abhidhamma material, the context of the sentence confused me.</p>

<blockquote>
  <p>In the Sarvāstivādin tradition since the compilation of the Dharmaskhanda, three unconditioned dharmas have been recognized: analytical cessation (pratisankhayā-nirodha), nonanalytical cessation (apratisankhayā-nirodha) and space (ākāśa). In the Theravada tradition, only one unconditioned dharma, nirvana, is recognized [...]. According to the Samaya, the Mahāsanghika, Ekavyavahārika, Lokottaravādin, and Kaukutica schools all recognized the following nine unconditioned dharmas: (1) analytical cessation (2) nonanalytical cessation (3) space (4) the realm of infinity of space (5) the realm of infinity of consciousness (6) the realm of nothingness (7) the realm of neither consciousness nor unconsciousness (8) the law of dependent origination (9) the law of the noble path [...]. The Sarvāstivādins disagreed with this position and did not recognize the existence of a principle of Dependend Origination separate from conditioned dharmas. For the Sarvāstivādins, the law of Dependend Origination itself was conditioned.</p>
  
  <p>For the Mahaśiśākas, the path to nirvana was recognized as an unconditioned dharma because the practices established by the Buddha were considered to be eternal truths. The Sarvāstivādins opposed this position by maintaining that although nirvana was unconditioned, the wisdom the Buddha had realized was conditioned and not eternal.</p>
</blockquote>
