I think the person you are responding to is using a strange definition of "know."
I think they mean "do we understand how they process information to produce their outputs" (i.e., do we have an analytical description of the function they are trying to approximate).
You and I mean, we understand the training process that produces their behaviour (and this training process is mainly standard statistical modelling / ML).
I think they mean "do we understand how they process information to produce their outputs" (i.e., do we have an analytical description of the function they are trying to approximate).
You and I mean, we understand the training process that produces their behaviour (and this training process is mainly standard statistical modelling / ML).
In short, both sides are talking past each other.