Interestingly, a method for invisibility is said to be firstly to not draw conclusions with your mind and then to forget about being visible. This sounds neat, because it implies to me that we always gave matter it's properties.
Further abilities go on from there.
I have the harvard edition of this text. Where are you getting your information from?
pharmakeia
Why is it assumed that it is only our own perception of visibility that controls our visibility? Others have perceptions of our visibility too, so I don't see why theirs couldn't affect it as well.
The key to invisibility is not solely internal.