"All of this" vs "All of these"

In the context of your question, "all this" means many things taken as a single whole. "All these" means many things as part of the whole; not everything.

For example I might be a boss pointing to a room full of boxes and say, "all of this needs to be moved into the next room." I can use the word 'this" because I mean everything. It is taken as a whole.

If I meant only some of the boxes, or if a mistake could be made if I'm not specific, I would point to specific boxes I wanted moved and say, "all of these need to be moved into the next room."

Another example I can think of is something I can picture from the movies: a rich guy looking out at all the land he owns with his son beside him. He waves his arm and says, "one day all this will belong to you." He means everything. The whole. Even if all his land is made up of individual items he would not say, "all these will be yours." It might be correct, but it also implies he is only talking about certain parts of the things in front of him. The son would ask, "which of these will be mine?"

Another distinction between all of this and all of these may turn on whether the all consists of material that is likely to be individually enumerated or taken as an uncounted mass.

The lot was filled with ping-pong balls. The owner said, "Take all of this to the dump."

In contrast:

The lot was filled with old cars. The owner said, "Take all of these to the dump."

While the ping-pong balls could be counted, they are insignificant enough to deal with as a collective mass. The cars, less so.

Logically, 'this' is singular. So the determiner 'all' is redundant, because only one of the subjects can be referred to as 'this'. Hence 'all this' cannot refer to a subject that indicates a singular object or item.

It follows that 'all this' must refer to the individual elements making up the totality of the subject.

However, it should be noted that sometimes 'all this' does refer to a single entity. Compare:

"He was the one who ate this cake"

and

"He was the one who ate all this cake",

where "all this" emphasises the subject's feat of eating the whole cake all by himself.

"Your answer is verbose and repetitious. Can you edit it to make it clearer and focused on the essential points?" - Eric Kowal

I was trying to be clear, Eric, but point taken.

Example 1:  Take all this pencil and write your name down.
Example 2:  Take all these pencils and sharpen them.

Example 1 makes no sense. "Pencil" is already singular, so it should be, "Take this pencil...". Example 2 makes sense with the "all" included because "pencils" is plural.

Therefore, the expression "all this" or "all of this" cannot refer normally to a singular noun, but to a collective (list, row, pile, etc) or uncountable (water, rubbish, etc) noun.

The exception is when the phrase is used for emphasis:

Example 3:  He built all (of) this boat himself.

This is to emphasise that he built the boat all by himself, with no help whatsoever.

" Participants commonly report increased mental clarity, improved quality of sleep, higher energy levels, and better moods. You can achieve all of this WITHOUT . I'd rather change the sentence structure and write instead: " Participants commonly report increased mental clarity, improved quality of sleep, higher energy levels, and better moods, all of which could be achieved without.....