I am reading Practical Insight Meditation: Basic and progressive stages by Mahasi Sayadaw. In the book he elaborates on the 16 stages of insight meditation as a kind of road map of what to expect. I was wondering if these stages are part of the Theravada tradition or an integral part of the Dharma canon.
Seven Stages of Purification is summerised in the Visuddhimagga (The Path of Purification)
the seven visuddhis come from the Ratha-vinita Sutta (MN 24), and the sixteen stages of knowledge are found in the Patisambhidamagga. – yuttadhammo
This comparison between practice and "seven relay chariots" points at the goal. Each purity is needed to attain the next. They are often referred to as the "Seven Stages of Purification" (satta-visuddhi):
Purification of Conduct (sīla-visuddhi) Purification of Mind (citta-visuddhi) Purification of View (ditthi-visuddhi) Purification by Overcoming Doubt (kankha-vitarana-visuddhi) Purification by Knowledge and Vision of What Is Path and Not Path (maggamagga-ñanadassana-visuddhi) Purification by Knowledge and Vision of the Course of Practice (patipada-ñanadassana-visuddhi) Knowledge of contemplation of rise and fall (udayabbayanupassana-nana) Knowledge of contemplation of dissolution (bhanganupassana-nana) Knowledge of appearance as terror (bhayatupatthana-nana) Knowledge of contemplation of danger (adinavanupassana-nana) Knowledge of contemplation of dispassion (nibbidanupassana-nana) Knowledge of desire for deliverance (muncitukamyata-nana) Knowledge of contemplation of reflection (patisankhanupassana-nana) Knowledge of equanimity about formations (sankharupekka-nana) Conformity knowledge (anuloma-nana) Purification by Knowledge and Vision (ñanadassana-visuddhi) Change of lineage The first path and fruit The second path and fruit The third path and fruit The fourth path and fruit
The "Purification by Knowledge and Vision" is the culmination of the practice, in four stages leading to liberation and Nirvana.
The emphasis in this system is on understanding the three marks of existence, dukkha, anatta, anicca. This emphasis is recognizable in the value that is given to vipassana over samatha, especially in the contemporary vipassana movement.
The earliest source for the enumeration of sixteen stages of knowledge that I know of is the Paṭisambhidāmagga, a treatise ascribed to Sāriputta, included in the Myanmar version of the Khuddaka Nikāya. So yeah, pretty standard Theravada.
Discussion of the knowledges is found throughout the commentaries and makes up most of the section on wisdom in the Visuddhimagga. They are also enumerated in the Abhidhammattha-Sangaha, a famous summary of the Abhidhamma.
Reference to each of the knowledges can be found in the Buddha's words, for example:
yo ca vassasataṃ jīve, apassaṃ udayabbayaṃ.
ekāhaṃ jīvitaṃ seyyo, passato udayabbayaṃ.
-- Dhp. 113
“katamā cānanda, ādīnavasaññā? idhānanda, bhikkhu araññagato vā rukkhamūlagato vā suññāgāragato vā iti paṭisañcikkhati — ‘bahudukkho kho ayaṃ kāyo bahuādīnavo? iti imasmiṃ kāye vividhā ābādhā uppajjanti, seyyathidaṃ — cakkhurogo sotarogo ghānarogo jivhārogo kāyarogo sīsarogo kaṇṇarogo mukharogo dantarogo oṭṭharogo kāso sāso pināso ḍāho jaro kucchirogo mucchā pakkhandikā sūlā visūcikā kuṭṭhaṃ gaṇḍo kilāso soso apamāro daddu kaṇḍu kacchu nakhasā vitacchikā lohitaṃ pittaṃ madhumeho aṃsā piḷakā bhagandalā pittasamuṭṭhānā ābādhā semhasamuṭṭhānā ābādhā vātasamuṭṭhānā ābādhā sannipātikā ābādhā utupariṇāmajā ābādhā visamaparihārajā ābādhā opakkamikā ābādhā kammavipākajā ābādhā sītaṃ uṇhaṃ jighacchā pipāsā uccāro passāvo’ti. iti imasmiṃ kāye ādīnavānupassī viharati. ayaṃ vuccatānanda, ādīnavasaññā.
-- AN 10.60
“sabbe saṅkhārā aniccā””ti, yadā paññāya passati.
atha nibbindati dukkhe, esa maggo visuddhiyā.
-- Dhp 277
I believe they are later addition. I have never come across any sutta or Buddha-Wajana about the 16 stages of insight. Let me know if you saw one.
I believe in Dasuttara Sutta in Dīghanikāya, while discussing Nines, Buddha lists 9 Visuddhis, not just 7, as are explained in Vusiddhimaggo. The nine are: 1. Sīlavisuddhi 2. Cittavisuddhi 3. Ditthīvisuddhi 4. Kankhavitarana Visuddhi 5. Maggāmagga Ñanadassana Visuddhi 6. Patipadā Ñanadassana Visuddhi 7. Ñanadassana Visuddhi 8. Pañña Visuddhi 9. Vimutti Visuddhi
I hope that makes it clear that Visuddhis are not later additions then.