Words Mean Things - And Opposite Things

In Charles Dickens' The Posthumous Papers of the Pickwick Club (Chapter VI), Mr. Tupman is wounded by a small bore "rook rifle" shotgun, when Mr. Winkle demonstrates what happens when you ignore three or four of the rules of gun safety. Pickwick, Snodgrass, and Winkle then depart to enjoy a local cricket match with their host Mr. Wardle, leaving Tupman "in charge of" the ladies of the household. Dickens is not saying that Tupman has been vested with authority to police the ladies' behavior. Quite the opposite. The ladies are to see to the well-being of Tupman.

When did the change in meaning occur? How is it that words can flip meanings?

Then there's Subject and Object. Some time between the 12th and the 21st centuries, Subject and Object passed each other going in opposite directions on the towpath of language, and as they passed they traded meanings. "Subjective" used to mean, "of or pertaining to the subject," where "subject" meant the thing being "subjected" to scrutiny.  Now, of course, the subject of scrutiny is called the "object", and if you object to that, you will be subjected to the ignominy of being misunderstood.  What you study is the "object", unless you're talking about your school schedule -- in which case you still study the "subjects" on the list. The final lens on a microscope or telescope is the "objective" lens.  But how handy to introverts it could be when attending a social function, to be able to pull out a little lorgnette or pince-nez or opera glasses holding high-quality subjective lenses!  Perhaps then the (unspoken) object of the person talking to you would be magnified, their point revealed. All the feels they subjectively hold, all the bias they subjectively project, would be visible in shifting pleochroic auras under an optical-quality subjective lens!

And if I were to look at myself in a mirror through the subjective lenses of my hypothetical binoculars, would I stumble across the threshold of some kind of Burnsian satori?

O wad some Pow'r the giftie gie us
To see oursels as ithers see us!

On second thought, I will pass on the subjective lenses and go on seeing myself as richer, younger, healthier, and handsomer than I may look to "ithers."