As most readers know, Philipp Maas (elaborating on a short article by Johannes Bronkhorst) has claimed that it is highly probable that an independent Yogasūtra never existed and that we should therefore only speak of the Pātañjalayogaśāstra, a work including what is known as Yogasūtra and what is known as Yogabhāṣya. He notices that the Yogasūtra is not independently transmitted, that all quotes until the 11th c. refer to either the YS or the YBh in the same way, as if they were the same work. For more details, see section 2 of his article in Franco 2013 (available here) and his article in Bronkhorst 2010 (available here).
Federico Squarcini recently disputed this claim
A basic bibliography on textual reuse can be found at the end of my Introduction to the Reuse of Texts in Indian Philosophy, available Open Access on Academia.edu and on the website of the Journal of Indian Philosophy. Apart from these titles, you might want to know about a few others which have been published thereafter or are now forthcoming:
What does it mean for a Sanskrit author to reuse previously composed texts, concepts or images? What does (s)he want to achieve by doing it? On these topics, I am currently in the process of finishing a volume I edited together with Philipp Maas namely, Adaptive Reuse in premodern South Asian Texts and Contexts (or perhaps Adaptive Reuse. Reflections on its Practice in Pre-modern South Asia), to appaear in the series ‘Abhandlungen für die Kunde des Morgenlandes’, Harrassowitz: Wiesbaden.
Some authors tend to think that once upon a time there was one Yoga and that later this has been “altered” or has at least “evolved” into many forms. According to their own stand, they might look at this developments as meaningful adaptations or as soulless metamorphoseis.
We need categories in order to think clearly about problems, but we do not want categories which block our thinking, nor artificial ones. And this applies all the more to an almost new field, like that of reuse.
What determines the likelihood of textual reuse to occur? The genre, the time, the personality of the author? And what are the reasons for not naming one’s source?
Are the categories we use while talking about textual reuse fit also for reuse in art?
The idea that the Yogasūtra (henceforth YS) and the Yogabhāṣya (henceforth YBh) are not two distinct texts has been discussed for the first way in a systematic way by Johannes Bronkhorst in 1985 (“Patañjali and the Yoga Sūtras”, Studien zur Indologie und Iranistik). Philipp Maas in his published PhD thesis (Maas 2006) examined it again and Philipp Maas in his contribution to Eli Franco’s Periodization and Historiography of Indian Philosophy (2013) dealt with it again in greater detail.
Today I read in Philipp Maas’s contribution to Periodization and Historiography of Indian Philosophy (edited by Eli Franco) an intriguing critique of Colebrook and of all the Indologists who, seemingly following him, thought that there was nothing philosophical in Yoga apart from its Sāṅkhya component and that what was typical of Yoga alone was not philosophical.