Difference between "this" and "that"

I always use them reversibly since I'm not too sure about their differences.

For instance, in an email I just wrote:

• solution 1


• solution 2

Which one of those solutions do you prefer?

I'm not too sure whether I should use these or those. In the above example I used those because it sounds cooler, maybe not the best way to choose...

Also I read that that is used appointing what is far while this is for close things. But in my example are solutions far or close?

Answer

My hometown had a shop where the owner made three kinds of donuts every morning: plain donuts, powdered sugar donuts, and cinnamon donuts. He also had a sign above each tray of donuts; the signs read THEM, THESE, and THOSE.

During the day, customers would make requests, such as, "I'd like two cinnamon donuts, and a plain donut," and whoever was behind the counter would put those in a bag. But if the shop owner happened to be behind the corner – mind you, this man was known for being a little eccentric – he would look at you as if he didn't understand, and say something like, "Look, we have Them, These, and Those – now what can I get for ya?" whereby the customer would have to say, "I'll take one of Them, and two of Those."

I always marveled at the way, no matter what combination of donuts you were ordering, you could still create a grammatically correct sentence using his names for the donuts, such as, "I'd like three of them, one of these, and two of those."

My point for relating this story is that sometimes these words (those words?) can be used interchangeably, with little or no change in meaning.

I'd say that, in the general case, these seems to imply closer proximity then those (as in, "These marbles [in my hand] look very pretty, but those marbles [behind the counter] don't look as nice.") However, as the donut example illustrates, even this generality doesn't always hold true.

Back to your example: I think you could have used either these or those, and, much like at the donut counter, either word would work just fine.