For a reductive materialist, yes, because when they say "I am in pain" they are talking about their brains. A collection of facts X about the brain is not necessary for the acknowledgement of another collection of facts Y about the brain.

See the analogous case:

Tribesmen see an LED. They have no clue what transition metals are, what diodes are, what photons are, what a catode is. Yet, when the LED shines red, they say "the liver is red", when it shines blue, "the liver is blue". They think that LED is the thing purifying their bodies of all toxins, so they call it liver. Nonetheless, they are still correctly talking about LED states.

Of course there are different versions of it. But I used a simplified mainstream claim.

This view is known as reductive materialism or materialistic monism. It is based on the belief that the mind can either be identified or reduced to the brain (or body) activity. For a true materialist the ‘mind’ is nothing more than a way of describing certain electrical impulses and chemical processes in the brain and the rest of the body. Thoughts or emotions are mere folk terminology: consequently, the laws of nature govern these processes. — Dr. Nash Popovic

is Dr. Popovic himself a reductive materialist, or a materialist at all?

Tribesmen see an LED. They have no clue what transition metals are, what diodes are, what photons are, what a catode is. Yet, when the LED shines red, they say "the liver is red", when it shines blue, "the liver is blue". They think that LED is the thing purifying their bodies of all toxins, so they call it liver. Nonetheless, they are still correctly talking about LED states. — Lionino

Are you claiming that exchanging meaningful information about LED lights entails exchanging meaningful information about transition metals and photons and everything else that an LED is? Suppose two children are talking about how bright the sun is. Is your claim that they are also talking about photons and fusion and just don't know it?

Also, the photons the cavemen are seeing being emitted from the LED's (and causing their erroneous beliefs about the LED's) are not identical to the LED's themselves, in the way that brain states are supposedly identical to mental states.

Also, in your example, the tribesman have an erroneous belief LED's and livers. The children in my example don't have erroneous beliefs about their mental states (or what's causing them, since they have no beliefs about brains at all). Can you give an example where no erroneous beliefs are going on?

is Dr. Popovic himself a reductive materialist, or a materialist at all? — flannel jesus

I don't know. From what I have seen, I am not even sure whether he is a proper doctor (his work seems to be on management and business), but I found that summary on his website and found it sufficient.

Are you claiming that exchanging meaningful information about LED lights entails exchanging meaningful information about transition metals and photons and everything else that an LED is? — RogueAI

No, I am claiming one is a collection of facts Y about the LED and the other a collection of facts X, you don't need X for Y neither Y for X, even though X would give you a deeper understanding of Y.

Suppose two children are talking about how bright the sun is. Is your claim that they are also talking about photons and fusion and just don't know it? — RogueAI

As above, no. But on this special case, talking about how bright the sun is involves photons, so those two facts are more closely related than the colour of an LED and it having a diode inside. The brightness of a star is a consequence of its fusion, but they are not talking fusion itself, like to talk about wetness is not to talk about the rain.

Also, the photons the cavemen are seeing being emitted from the LED's (and causing their erroneous beliefs about the LED's) are not identical to the LED's themselves — RogueAI

The photons an LED emit define its colours, so they are talking about the LED when they say the LED is red.

Also, in your example, the tribesman have an erroneous belief LED's and livers — RogueAI

Just like Ancient Greeks talking about brain states when they say "I feel pain" and not knowing much about the brain. That is the point.

Can you give an example where no erroneous beliefs are going on? — RogueAI

I think therefore I am? I don't understand the question.

Are you claiming that exchanging meaningful information about LED lights entails exchanging meaningful information about transition metals and photons and everything else that an LED is?
— RogueAI

No, I am claiming one is a collection of facts Y about the LED and the other a collection of facts X, you don't need X for Y neither Y for X, even though X would give you a deeper understanding of Y. — Lionino

But you are claiming that exchanging meaningful information about mental states entails exchanging meaningful information about brain states. Why aren't the facts about the mental states collection of facts Y and the facts about the brain states collections of facts X?

Why aren't the facts about the mental states collection of facts Y and the facts about the brain states collections of facts X? — RogueAI

Assuming you are referring to X being "I am alarmed" and Y beng "hypophysis releasing adrenaline", because for reductive materialism they are the same as saying "Batman is 190cm tall" and "Bruce Wayne is 190cm tall". You may disagree with it, but until you refute it, you can't say your theory denying RM is proven rather than a mere possibility.

1. Mental states are identical to brain states.
2. From (1), talk of mental states is the same as talk of brain states.
3. Ancient peoples coherently talked about their mental states.
4. Ancient peoples did not coherently talk about their brain states.
5. Therefore, mental states are not identical to brain states. — RogueAI

Is the logic what you wish to discuss or do you wish to discuss whether brain states are "identical" to mental states.?

The logic is at least flawed prima facie. And if brain states are not "identical" to mental states for all (including the Ancient Greeks), then brain states are not "identical" to mental states.

Please advise.

"Identical" is a strange wording that's prone to confusion due to different people's understanding of what that exactly entails. That's why most philosophers talk in terms of supervenience instead.

Identical" is a strange wording that's prone to confusion due to different people's understanding of what that exactly entails. That's why most philosophers talk in terms of supervenience instead. — flannel jesus

I agree.

1. Mental states are identical to brain states. — RogueAI

Are they? And does it matter to your argument? You seem to be suggesting that the Ancient Greeks did not have brain states because they did not talk about them. And if they did have them but not talk about them, why would the "identical" relationship between brain states and mental states be any different for Ancient Greeks than for others?