Does the meaning of the sentence change if we substitute on and upon?
Some sentences-
The book is on the table.
I took upon his emotional burdens.
I remain firm on my stance.
I have noticed that upon is used more in idiomatic expressions(unlike the third sentence I presented, though), but what is the difference in their meaning? Is there any other way besides intuition to understand which preposition to use of the two?
Although this definition suggests that "upon" is simply a one-to-one replacement for "on," there are some constructions that don't work with both. "Take on" can mean "adopt," "take on [-to myself]," so the second example would be either "I took on his emotional burdens" or "I took his emotional burdens upon myself."
In the third example, in which "on" is synonymous with "about" or "with regard to," "upon" is idiomatically inappropriate. (If you said, "Upon the topic of __," it could be appropriate, but as with just about any valid use, somewhat archaic, as the definition above notes.)
In the first example, you could change "on" to "upon" with no change to meaning, but definitely an archaic usage.
