Nirvana or the awakened state is often said to be indescribable, and typically understood as permanent. We’ll consider both of these claims, and look at a neat thought experiment by philosopher Frank Jackson along the way.
The Unconditioned (SN 43.12, 14-43) (The rest of this sutta appears not to be available online).
The Second Discourse About Dabba (Ud. 8.10) (Slightly different translation).
The Exposition of the Elements (MN 140)
Greater Discourse on the Simile of the Heartwood (MN 29)
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