Hi Again,
As retro pointed out, I think it is acceptable as long as one back-up this with sutta quotes and careful Dhamma analysis and it is respectful of others (well, actually one can be right even if it is not respectful, but since this is the Dhamma and we are not the Buddha...). For example (always imHo) I think that Thanissaro really got Anatta right if we want reference the suttas alone and we make the exercise to not be conditioned by tradition. He also clearly explained the drawbacks of other interpretations. My take, of course, but he certainly did his best to substantiate his case and explain why it is important to raise the discussion on the point.However, the problem I see with some teachers is that they start with: "some (unspecified - hard to tell who they are) teachers teach such and such..." and go on to imply that anyone not teaching exactly what they are teaching is also flawed.
In this case I'm not sure what you mean by "vipassana". There's a huge difference between lay teachers, Goenka retreats, monastics or former monastics who spent time in Burma with U Pandita, and so on... Are those all "vipassana"?
It is a wild and differentiate place, but you got it. I think that actually the worst are the less famous disciples that teaches vipassana like this:
I think that actually is the proliferation of teachings like this one that comes from the root of the Vipassana movement (Goenka, U Ba Khin, Goldstein, Kornfield) that muddled the waters of the Dhamma in many places. Not so much the big names since Goldstein for examples teaches also about detachment and such or also Mahasi is way way more profound and nuanced, but the myriad of less-known teachers.Awakening to Impermanence In a Nutshell:
Our entire reality is fabricated by an intricate dance of sensations. We need to understand this clearly in order to awaken.
One reliable way this can be achieved is through high-resolution perception of rapidly changing sensations at a rate of 1-10 times per second. Whether a sensation is pleasant, unpleasant or neutral doesn’t matter one little bit in Vipassana practice.
When sensations are perceived this rapidly, the mind eventually flips over to cognizing impermanence directly by default all of the time. While initially requiring effort, once the ‘switch’ is flicked we can relax into this new vastly superior reality.
We see through our own experience that nothing lasts for even a microsecond.
We shatter the illusion of continuity and experience a hyper-present reality
This example I gave, I think, demonstrably unrelated to what is there in the suttas. No link of impermanence to what is dear or acquired, no references in the suttas about microseconds, better reality are due to detachment and letting go in suttas. If one takes this as impermanence, it is no wonder that the link with Dukkha and detachment is hard to impossible to see. And then people abandon the Dhamma, because Impermanence is linked to an almost esoteric reality to discover, and not to the unreliability of clinging that is so crucial in the 4nt.