word "mental" properly refers to those of us thinking about object

I think that's what it means. Of course, in real life the pear tree and the cherry tree have plenty of differences, even if we are unable to perceive them. One of the articles I found in my googlssey for "subservience" referred to the Riddle of the Stopped Clock, and seemed to be saying that, since the Stopped Clock was no longer indicating the passage of time that it was somehow "outside of time." Either I was misinterpreting what I had read or the author is in bad need of a philosphectomy.