SuttaCentral
Thank you for explaining your thought process. I haven’t made up my mind on this issue personally.
Regardless of any objective world, suffering is a subjective reality. I.e. it doesn’t seem that our beliefs about an external reality changes the consistency of the Dhamma regarding subjective suffering, since suffering basically “exists inside” subjective experience.
I don’t think the Buddha claimed that “all conditioned phenomena is dependent on clinging.” 
I think he claimed that “all conditional (the translation that I prefer) is dependent on conditions” without necessarily specifying which conditions they were because the conditions for different phenomena are different.
With regard to dukkha, I think the Buddha traced the origin back to “thirst, psychological thirst, ‘craving,’ etc.” - not clinging. Clinging is considered dependent on craving, so I am not sure why in pop culture Buddhism, the Buddha is portrayed as having identified the cause of dukkha to be “clinging,” when it seems like the cause was actually traced back to thirst/tanha.
On what basis? I hear this negation of the external world a lot in spiritual and Buddhist circles (drawing comparisons to Matrix and such), but I am not sure where the Buddha ever denied that “it is impossible for a being to verify whether the external world exists or nor.”
The Buddha was capable of perceiving. But he had uprooted clinging by then.
Yes, after he passed away, not more perceptions would arise ever again after that, but the relationship doesn’t seem to be the way you stated it.
What sounds unreliable?
As I mentioned in my previous message, I agreed that both Buddhism and evolutionary biology agree that “immediate perception” is unreliable. However, I don’t think Buddhism goes to the extreme to say it is impossible to understand whether there is an external world or not, let alone understand it.
Welcome.
No problem. Let me know if you come across any other relevant information that leads you to conclude one way or the other. I am open to the fact that my view might be wrong, and I would not want to hold wrong views out of fear of where this leads one who holds such views. Thanks in advance.
I am not sure if this claim is true.
From my perspective, it seems like the Buddha is making a claim about objective reality.
“This is dukkha,” “this” likely referring to something that is occurring in actuality, in objective reality that beings can observe and verify independent of him.
His definition of dukkha doesn’t seem to include just suffering in the sense of mental suffering, but actual, real death, which is objective. For example, when coronavirus kills an individual, its not just a subjective experience of the being who died - it’s something that occurred in reality that objectively happened.
Subjective is often used to mean that two contradictory things can be the case for two different people and still both be true. For example, “person A can like color B and dislike color C” and “person D can dislike color B and like color C.” Color B is likable for person A and unlikable for person D - that is contradictory, but because it is subjective, it is still very much possible.
The four noble truths seems completely objective.
A is the problem (of dukkha).
B is the cause.
C is the end.
D is the way to the end.
If someone claims:
A is not the problem (of dukkha).
B is not the cause.
C is not the end.
D is not the way to the end.
then they would be making a claim that is NOT compatible with the Buddha’s claim regarding what is actually the case (“objective reality”).
In fact, we see that this is indeed the case in other religions - that is why Buddhism is distinct from other religions in that they make objective claims that are not (entirely) compatible with the claims made by other individuals and groups.
For example, I have heard people say something along the lines of: “death is not suffering, its the subjective experience of death that is suffering. A person who died unhappily suffered whereas a person who died happily did not suffer. Why? Because suffering is subjective to the individual.”
I think that the Buddha would disagree with this claim saying that in both cases, the death experienced by the individual was objectively dukkha - if that being had not been born, he would not have had to experience death. He might acknowledge that in addition to that death being suffering, the person who died unhappily “suffered even more.”
In this vein, I sometimes think that the simile of two arrows might be misinterpreted: Sallatha Sutta: The Arrow
Sometimes it seems to be interpreted as there are two sufferings, a physical and mental suffering.
A foolish being:
feels two pains, physical & mental.
A wise being:
He feels one pain: physical, but not mental.
I agree with this part so far.
But sometimes, I think people wrongly infer that the end of dukkha means the end of mental pain only, but not the end of physical pain.
To me, it seems like developing the Noble Eightfold Path leads to the end of both physical and mental pain and suffering, including injury, death, material loss, etc. - not just to subjective mental pains.
Yes, during the lifetime of say, an “instructed, extraordinary person,” such a being might feel only the physical pain stated in the discourse, but the end of dukkha also seems to imply that such a being will, after having passed away, never feel physical pain ever again. Neither mental nor physical pain will ever arise for him again.
In contrast, the “uninstructed, ordinary person” will continue to experience dukkha indefinitely and perpetually into the future, so long as the cause of it, tanha, remains in his/her mind.
This is why I think that dukkha or suffering is an objective reality, not merely a subjective reality.
The same way doctors can observe patients becoming old, sick, and dying, it seems that monastics and laypeople can (potentially) observe all beings become old, sick, and die. Not merely a subjective thing, but something that occurs in actuality, in reality.
Those who develop the Noble Eightfold Path sufficiently seem to reach a state where they never again become old, fall sick, or die. Not just subjectively, but they will literally never actually die again in reality - or at least that seems to be what the Buddha’s claim is, since I can’t speak on this from personal experience.
It’s all in dependent origination (perception is in nāmarūpa, clinging is its own link). At least, as I understand it. Also, I am talking in only a phenomenological sense, rather than ontological. As far as I am concerned, if I cannot perceive it it doesn’t exist. Perception is a necessary condition for everything.
Fair enough. Craving is the one mentioned in the four noble truths, yes. But craving and clinging are both dependent on each other. You could just as easily say that avijjā/ignorance is the cause of suffering. It’s all the same thing–it all arises together. Personally, I tend to mention clinging more than craving simply because I find it a more helpful example.
Well, I think the Buddha avoided those sorts of questions entirely, didn’t he?
When it comes to ending suffering, I think believing in a reified, concrete, “objective” world is an invitation for dukkha to come barging in. Because how will I tell the difference between what is “real” and what is “illusion”? Is the pain in my leg real, or is just a perception? Which is a more helpful viewpoint?
This is something I think the Pali canon leaves unexplained. Perhaps because the question doesn’t apply. As non-Arahants, we have five clinging-aggregates through which we experience the world. Arahants/Buddhas do not have clinging, so how do they experience anything? (I think there is a distinction made at some point in the canon between aggregates and clinging-aggregates, but the difference is not clear). I would love to hear anyone’s thoughts on this. I have a couple ideas, but I will spare you. 
I just meant that if a creature is subject to craving and clinging, the “objectivity” of their perception should definitely be in question.
It might be helpful to define what you mean by objective.
The way I see it, you can have objective as in “something that is true or exists independently of human perception”.
E.g. an apple and the redness of an apple exists independently of human perception. The smell of orange exists independently of human perception. Sometimes these independent objects enter the sensory range of human beings, and they experience them.
Or you can have a weaker form of objective (consensus objectivity) as in “every reasonable person acting in good faith would come to the same conclusion given enough time”.
E.g. everyone would agree that an apple is red, that oranges smell a certain way, therefore it is objective.
I would say death is not objective (in the first sense), since it is a concept that only has meaning in the context of human experience. I’m guessing we’re using the word differently.
But I would say death is objective in the consensus sense; any living being (in good faith, given enough time to contemplate it) would agree that death happens and that it has some serious implications regarding existence.
Edit: for reference: https://en.wikipedia.org/wiki/Objectivity_(philosophy)
Edit2: To me, suffering is objective in the sense that any conscious being with the necessary mental faculties, if in good faith, given enough time, would come to the conclusion that suffering is an inherent part of conscious experience
For a fish to understand “dryness”, it must leave the ocean. But it need not be killed, dried out, and sent into space as a desiccated remainder utterly devoid of a single molecule of H20. Dryness is not absolute.
And nor is the suspension of time. Obviously in some sense, the experience of jhana is conditioned and hence subject to impermanence and time. Yet to a person in jhana, time does not exist in a profound way that is quite unlike ordinary sense experience.
From a Buddhist point of view, time is a concept derived from the memory of changes in consciousness. Unlike Vedanta, we do not assume an absolute time. Thus to alter the perception of time is to alter time itself. This is much the same as modern scientific notions of time, where time is simply a measure of the rate of change, it has no independent meaning. This is why time moves at a different rate for astronauts moving near the speed of light.
I really try to avoid reading too much into it, but I cannot help but notice that in physics, time effectively stops when you become a photon. And in Buddhism, time stops when you absorb into the light of jhana.
Comparatively, Hoffman’s argument is that time (and 3-dimensional space) do not exist objectively, but are data structures that we use to compute fitness payoffs of various actions.
I.e. our perception of time is just a way to reason about, for example, the amount of energy needed to do some action or achieve some outcome.
I don’t think the absence of time implies any sort of permanence. As far as I can tell, in the suttas impermanence comes from causality, i.e. the fact that all phenomena arise and cease due to causes.