Okay, they bring many quotations there from medieval authorities (Rishonim) and later authorities (Acharonim): some wrote that it’s possible and some wrote that it isn’t. What do you think, and how can this be checked?

I asked you to define the question. Preferably with an example.

Sorry, but it’s not really clear to me what needs defining. The question is whether a person can think two thoughts at the same time.

For example, we find in Meiri on Gittin 53a: “for it is impossible for a person to focus on two things at once.” And similarly it is found in a manuscript of Rabbi Judah the Pious: “A person cannot think two thoughts.” And there are more such statements among the medieval authorities (Rishonim) and later authorities (Acharonim). On the other hand, we find that some wrote that it is possible. And some wrote that certain special people were granted two brains (from this?), and therefore it is possible.

I understand that maybe it isn’t clear how to approach and handle the question. But that’s exactly why I asked. Do you have any idea what clarifies this and how one would clarify it?

You wrote “about one matter,” not “at the same time.” I expect questions to be phrased clearly, especially when I ask for that again. I answer every question willingly, but I’m sorry to spend unnecessary time investigating what the question means.
I don’t know whether it’s possible. It may be, perhaps if one is verbal and the other is not.