Hi retro and tilt,
retrofuturist wrote:It's the various modern definitions of 'dhamma' that obscure the basic agreement.
Yes, I think that's a possibility in many cases when we loose sight of discussing experiences and drift away into upholding opinions/positions.
retrofuturist wrote:However, if someone really was "reifying dhammas as little bits of existing things that pop in and out of existence", their experience of a dhamma could be nothing other than conceptual and speculative given the supposed billion cittas per flash of lightning. Seeing that many rises and falls of individual cittas is, dare I say it, impossible and unnecessary.
Yes, it's possible that things are as you say. At the moment, I can't really tell one way or another about the speed from experience. More below.
retrofuturist wrote:Incidently, when trying to find that lightning quote, I stumbled across this old topic that may be of interest to you, which you may have since forgotten about... Provenance of the notion of momentariness in the Theravada
Sure I remember it, a heated thread that split from another even more heated thread

Regarding the speed and discrete moments of experience, I think I mentioned this already - sometimes it happens to me that the flow of experience in fact looks like a sequence of very fast pulses, or discrete instances. E.g. an arising of a certain sensation is seen as a very long sequence of very fast distinct pulses. I have no idea what is this, most probably just a meditation artefact. Of course, initially I thought "Hey, maybe these are individual cittas!" but that's not very likely - I mean the speed I experience now is not greater than maximum a hundred pulses per second, and that's pretty far away from a billion cittas per a flash of lightning.
But that's also why I'm not ready to dismiss the billion cittas thing. I mean, if I can experience near hundred pulses per second with my infant-level insight, then I wonder what would be the case for an arahat. So, at the moment I can't really comment with certainty on speed. Though, of course, it might be that seeing things at such high speeds is not necessary in the first place, i.e. it might be just one of those abilities that might develop with meditation, but are not crucial for liberation, just like the mundane abhinas which aren't necessary and which people who don't have them are more likely to dismiss as impossible, etc.
tiltbillings wrote:When you just sit, mindfully "seeing," without comment, and with a concentrated mind, the flow of one's experience where are the dhammas?
Usually, what I take for the flow of experience is just me imagining (without realising it of course) that I'm seeing the flow with mindfulness and awareness, but sometimes on rare occasions, usually in just a flash (more rarely in the form of a sequence of flashes/pulses), there happens an understanding that whatever arose (like a sensation of hardness) was a conditioned occurrence independent of my input so to speak (what I believe is in fact an experience of seeing anatta), and then this would be followed by a conceptual process making sense of what just happened.
That flash of experiencing a sensation and seeing anatta nature of it, that's what I'd call a dhamma with individual and general characteristics. Of course, objectively, it cannot be said that it arose alone, or independent of other dhammas in what you'd call the flow of experience, but that's what was cognised at the time when an instance of insight occurred, and that's why I tend to consider that a "dhamma", as an experiential equivalent of understanding the individual and general characteristic of an experienced instance, is the closest possible description of a moment of insight. But I don't think it really matter how we call it, as long as it truly happens and it's not just imagining that it happened.
Best wishes