I’ll get to the other issues soon, thanks everyone for posting. meanwhile, as it happens I recently had a chat with Ven Suddhaso on this very point:
I don’t care about consistency with PTS (or anyone else really) so much as accuracy. In this case, there is an alternate reading sabbato pahaṁ and it was long ago pointed out (I think by Nyanamoli) that in many respects this looks like a better reading. Previous discussion here:
Which includes a quote from Ven Analayo’s article.
Discourse parallels to the Kevaḍḍha-sutta extant in Sanskrit and Tibetan do not qualify the invisible consciousness as luminous. The same holds for a discourse quotation in the Mahāvibhāṣā. A reference to the present passage in the Ratnāvalī also does not mention any luminosity.
One of the basic principles I apply in my translations is the “principle of least meaning”. This means that when faced with a translation choice, I try to translate in a way that does not overburden the text with meaning.
That this is the case with the rendering “luminous” is attested by the many, many attempts to use this passage to support a pseudo-eternalist view of Nibbana as a state of consciousness. If this idea were well-attested elsewhere, other quotes would be used. The fact that this, a contested line without support of parallels, in a very specific narrative verse context, is so constantly called upon to redefine the very nature of the Buddha’s awakening should be a red flag.
This is exactly the fallacy I try to avoid with the “principle of least meaning”. It’s inconceivable that the Buddha would have avoided a clear and straightforward description of the goal of his practice, leaving only to a highly unusual chance encounter to reveal. Rather than freighting this one word with a meaning that invites a reassessment of the whole of the Buddha’s philosophy, it’s more plausible to see it saying the same thing as the Buddha said countless other times: let go of everything, even refined states of consciousness.
Not to say, however, that the reading sabbato pabhaṁ requires an eternalist interpretation. More likely it would simply refer to samadhi. But history shows that a lot of people are really determined to make the Buddha an Upanishadic non-dualist.