I think this is a good argument against epiphenomenalism, but I imagine the epiphenomenalist would say in response that epiphenomena correspond to physical phenomena, and it is the physical phenomenon whose epiphenomenon is pain (some brain state, say) that causes us to say “I’m in pain”. It might be, they would say, that there could be a philosophical zombie with all the same physical stuff going on who reports that it’s in pain, but doesn’t actually have the epihenomenon of really feeling pain.

I would ask them in turn why we need to posit epiphenomena at all; why can’t the physical stuff doing the causing also be having the experience by itself?

Yes, it is. It does not stand. But it is an amazing theory, cause it almost captures the essence of all processes: they are physic, real particles and forces. But it gets stupid when it refers to the mind as a distinct entity. The mind is also physics.

Pretty nearly yes. It would only be possible under extremely unlikely circumstances in my opinion. I talk about this in my thought-experiment thread.

But why would such a zombie ever come to exist evolutionarily even if it was technically conceptually possible?

But here's what I still don't understand after a decent amount of research:
1. Why would a zombie report pain?
a. where did the zombie have the notion of pain?
b. why would it mention it at all?
2. If it does mention it, isn't it a HUGE coincidence that all reports correspond to exactly the same epiphenomenon?

I have read a lot about this topic, and I admit sometimes things get too complicated for me. But from what I understand from Chalmers zombies is that the zombie world has to have some different physical laws in order to act exactly the same, and Chalmers kind of admits that.
Moreover, I don't understand the ''acquaintance'' argument. The acquaintance of whom? Of the physical with the epiphenomenal? And doesn't that mean that this acquaintance has an effect on the physical?
It might be the case this topic is too complicated for me.

It is also surprising for me that Sam and Annaka Harris endorse epiphenomenalism, it seems to have so little chance to be real, I thought Harris are success-oriented people, this seems to be a hard bet to win in my opinion.

Pretty nearly yes. It would only be possible under extremely unlikely circumstances in my opinion. I talk about this in my thought-experiment thread. — Francis

Is it because of the huge coincidence between reports and epiphenomenal states? Not only that, but it also looks like a law of nature to feel, for example, pain, every time you're being hit. And if epiphenomenalists claim that this is a psychophysical law, then they're wrong, because in some cases, pain produces pleasure. So only huge coincidence remains on the table.

Another thing, why on earth ''I'm in pain'' would even exist in a world with no feelings? Why the concept of pain in the first place? it's like something out of the blue, a non-sense.

But then again, sometimes I feel it's me who doesn't understand the topic.

By the way, if epiphenomenalism is true, why do we go watch comedy movies at the cinema?

I mean, I cannot see any reason to spend resources and precious time that could be used for reproduction, other than the pure need for feeling well and have a laugh, or, in other words, it's a feeling-driven act.

The mind is also physics. — Helder Afonso

So far, materialism has unsuccessfully tried to avoid the hard problem. The strongest theories so far are the identity theory and functionalism, both having serious fundamental flaws in my opinion. So your heavy statement is sitting on a sandy foundation.

Why would refer to the experience aspect? I suppose I could understand we might say and remember pain itself, but why would be refer to an epiphenomenon in general. Why would atoms bashing into eachother come up with that topic? And then it is referring to something that supposedly cannot be causal. But it seems like we creatures reacted to the existence of it - this epiphenomomen - and thus it because part of a chain of causes and effects. A pure epiphenomenon would never be mentioned.

Agree!
One of Chalmers' response was ''the acquaintance'' and to be fair, I do not understand it exactly, because this supposed acquaintance seems to me like a cause itself, a cause that would be missing in the zombie world.
By the way, nice to see you again, Coben!

If thoughts are epiphenomena, then the thought that thoughts are epiphenomena is itself an epiphenomenon, therefore it means nothing, and therefore it cannot be true. So indeed, epiphenomenalism is self-contradictory, as are most versions of materialism.

Even the concept of epiphenomenon is illogical, as it contradicts the law of reaction. If the brain can have an effect on the mind, THEN it follows necessarily that the mind can have an effect on the brain.

Action-reaction. But indeed, epiphenomenalists say that mind is not really physical. It's either immaterial (property dualism) or some kind of proto-phenomenal thing (Russellian monism).

The mind is evidently physical to a degree: it can be in pain, for instance, which often indicates a physical issue somewhere in the body, and it can direct the body to do all sorts of physical things...

I think there are correlations between mental states and what we call physical brain.

I think there’s more than correlation: there is causation. And it goes both ways, as required by the law of action-reaction.

I've read the Acquaintance Hypothesis and to be fair, I really don't understand:
1. When matter gets acquainted with consciousness, isn't that producing a cause already?
2. How does matter get acquainted with pain, love, thirst, etc. if these things are epiphenomenal? I don't get it!
Is there any other example in this world of acquaintance that produces no causes? I would like to know, maybe this way I'll understand this hypothesis better.

Epiphenominalists are often trying to accommodate scientific facts without discarding the reality of the mind. Various things happen that do not accord with the folk-psychology that all immediate experience must be shaped the way we generally discuss it in words. Instead, it is partly conditioned by the existence of words, and their purpose.

Only saw this now. The mind is physics. All is. We just don't have the knowledge yet and you choose to have some supernatural explanation for the things you do not know.