Materialists say that matter is the only thing that exists; there is no spirituality, no ideas, and nothing beyond the physical. All sensations, emotions, and desires arise from physical processes in the brain. We are robots, and anyone who knew how our brain works could control us however they wished.
Dualists say that in addition to matter there is also a spirit/soul, which is the entity that experiences things, loves, hates, thinks, etc., and it is not subject to the physical/chemical processes that the body undergoes.
When I was speaking with someone I work with, he asked me the above question in response to these points.
In addition to a few more magical examples, like a hard blow to the head with a club causing memory loss, and so on.

I asked for the definitions, and after that for the argument that you think is a proof.

Ask that same person in return: what substance is the color blue made of?

If he tries to explain it to you, he’s just an idiot.

Materialists say that matter is the only thing that exists; there is no spirituality, no ideas, and nothing beyond the physical. All sensations, emotions, and desires arise from physical processes in the brain. We are robots, and anyone who knew how our brain works could control us however they wished.
Dualists say that in addition to matter there is a spirit/soul, which is the entity that experiences things, loves, hates, thinks, etc., and it is not subject to the physical/chemical processes that the body undergoes.
So far, those are the definitions.

When a person drinks alcohol, chemical processes occur that affect his behavior; emotions intensify, thoughts become clouded, and all of this is unrelated to the soul, because if the soul were separate from matter, then chemical effects should not affect consciousness at all. Antidepressant medications affect mood through chemical processes, as do Ritalin, hard drugs, etc.
There are people who go through an accident and, because of brain damage, lose their memory. If memory is not part of the brain but rather something connected to the soul, then damage to the brain should not affect it at all.
If a person gets a hard enough blow to the head, gets his throat cut, jumps off a building, or drowns in the sea, there are no more thoughts, no more sensations, and no more desires. The brain dies, and with it consciousness. All this happens through damage to matter.

From this it follows that the source of consciousness is in matter.

When your head hits the wall, a sensation of pain is created in consciousness. Is that also a refutation of dualism?

Sorry, I don’t know.
I understand from you all that this is a beginner’s question, but I only recently came across it and didn’t have an answer…..

Never mind, you can delete it; I’ve now found and read an answer. Thanks, and sorry 🙂

What answer did you read?
And what does the Rabbi think about the question?

That’s already better, and now it can be discussed. Since you wrote that as far as you’re concerned it’s already been resolved, I’ll just say two things:
Materialism assumes that this is always the case and that it happens absolutely. (It’s important to add this to the definition of materialism.)
From here you can infer that phenomena like these do not prove that this is always the case (after all, these are just a few examples), and certainly do not prove that the influence is materialistic. The materialist assumes that the body determines the soul, and the dualist also agrees that there are influences. His claim is that this is influence, not determination. The body creates a pull in a certain direction, but the person can overcome it. Beyond that, one should not confuse influence with identity: when A influences B, that does not mean there is no B and everything is just A. They already asked you why go to these phenomena and not bring the case of a wound (a physical phenomenon) that creates pain (a mental phenomenon).
See at length in my book The Sciences of Freedom and in my article here on the site about free will:

מבט שיטתי על חופש הרצון

The materialist claims that there is no soul at all, doesn’t he?

That there is no soul as an object. It is an emergent phenomenon.