The materialist position is that the mind is an effect of biology and physics.
If the materialist appeals to a person’s mind (logic, reason, thoughts, conscience, emotion) to try and get them to change their views/beliefs, they are necessarily assuming that the mind is not limited to being only an effect of biology/physics, because they would be appealing to an effect (the mind) to change itself, or to itself act in a top-down, causal manner, circumventing the physical causes the materialist supposedly believes actually produces the state-of-mind effect.
Appealing to the minds of others necessarily means assuming those minds are not caused by biology/physics and that those minds have the causal ability to change themselves based on concepts and arguments. Since those concepts and arguments do not rely upon any particular physical medium of delivery in order for them to be considered by the mind of another – text, sound, braille – it obviously is not the expectation of the materialist that it is the nature of the physical medium employed that causes a physical reaction towards the change in mind – if so, why bother arranging words and sentences so carefully into arguments and concepts at all?
Who knows which string of perceived letters will have what effect on the mind of another? Wouldn’t you have to know the physiological cause and effect system that culminates in their caused mind to know which set of perceived letters will generate the desired effect? Yet, where do our materialist counterparts ever try to understand the physiological causes that generate our beliefs and views before they begin their argument? They act as if the actual physical, cause-and-effect interactions of medium and the physical state and physical processing mechanisms of the recipient are irrelevant!
Materialists argue and act as if the particular physical medium carrying their messages isn’t important at all, but rather that it is the mental concepts contained in the physical medium that is the important thing, as if the mind of the other person can comprehend the message regardless of the medium (conceptually top-down, not physically bottom-up), and as if changing the mind of the other person isn’t at all a matter of the biology and physics of the message-carrying medium, but rather of the argument and concepts regardless of the medium.
IOW, whenever a materialist argues, they can only do so based on non-materialist assumptions, and they do so in contradiction to their own stated core beliefs.