How to translate to english from a foreign language an idiom that uses two different words that have the same meaning “empty”, to say “pouring from empty to empty”, which means if you pour something from one empty vessel into another empty vessel your achieve nothing.
Specifically, I am asking for an idiom that means: talking about something again and again ( wasting time) without a real desire to solve a problem. What would be the nearest equivalent in English language?
"Beating a dead horse" means you are doing something that will have no effect (horses are hit with whips to make them run faster, but if your horse is dead, no amount of whipping will make it move)
There's no point trying to fix the photocopier; you're just beating a dead horse. It needs a new part so just wait until the repairman comes.
"Going round in circles" means making no progress to reach a decision.
John and his team have been going round in circles trying to design a new logo. John wants something simple but other people in the team keep adding details.
There are a number of related idioms, but these depend on context. The most straightforward way to explain is with a more-or-less direct translation:
Nothing gets you nothing.
This would make sense in a situation where you are expected to contribute something to achieve a result, i.e. "If you put in nothing, you get nothing back".
If, on the other hand, you want to say that you can't get something where nothing exists:
You can't get blood from a stone/turnip.
Typically this idiom is used when talking about asking someone for money, i.e. "You can't get money from them because they don't have any."
Another option, to suggest you can't make something fine from coarse material:
You can't make a silk purse from a sow's ear.
This is often metaphorically applied to people, for example:
My student says he wants to be an operatic singer, but completely he's tone-deaf. I don't know what he expects me to do -- after all, you can't make a silk purse from a sow's ear.
As others have mentioned, "flogging/beating a dead horse" means you can't get effort where there is none left. This is often applied in situations where someone has already made an effort to achieve a goal, to no avail:
He keeps trying to get his book published, but I think he is flogging a dead horse.
Another idiom that implies much effort and activity has been applied to no result
chasing one's tail
like an animal who goes round in circles. This can be used in the situation where you repeatedly talk over an issue without achieving any new insight, agreement, or progress:
The negotiations went on for hours, until the moderators called for a break, saying that the two parties were simply chasing their tails, and needed to approach the discussion from a different angle.
Lastly, an idiom based on historical events, to imply a well-meaning but ultimately futile effort:
rearrange the deck chairs on the Titanic
Obviously if the ship is sinking, there is no value in arranging the chairs in a way that might be more convenient. It can be applied to any failing enterprise:
The managers spent weeks looking for ways to cut costs, but all this was just rearranging deck chairs on the Titanic as the company's sales were half what they were the previous year, and falling.
The first thing that sprang to mind was “an exercise in futility”, or doing something that has no hope of achieving anything useful.
Trying to bail out the boat with my tea cup was an exercise in futility. The water was coming in too fast.
On the ELU thread that ColleenV linked to, J. Walker suggested spinning your wheels. When a car doesn't have any traction in mud or snow, pressing the accelerator just spins the wheels, and digs the car in deeper.
If the talk includes bold statements or heated arguments, you may have a tale[…] full of sound and fury, signifying nothing.
Robbing Peter to pay Paul: You still owe just as much, to just as many people, but you've now added the sin of stealing from Peter.
Mexican fire drill: A sedan has four passengers, one by each door. The car stops, everybody gets out, runs partway around the car, and gets in at a different door. A lot of rapid activity happens, for no significant change.
Perhaps the reason you have meetings where you "[talk] about [something] again and again without real desire to solve a problem" is that you have too many chiefs, and not enough Indians? In other words, lots of bosses, but nobody to do the real work.
Peeling the onion, in order to find its seeds. No matter how many layers you peel off the onion, you never will find any seeds. And the onion will be destroyed in the process. (Lois McMaster Bujold wrote a scene that she summarized with this phrase.)
If I had some ham, I could make a ham sandwich, if only I had some bread. A totally useless thing to say, because you don't have any of the ingredients for the thing you want to make. (If you don't eat ham, feel free to substitute the sandwich ingredient of your choice.)
Flogging a dead horse, perhaps?
I'm familiar with the Polish przelewać z pustego w próżne (pouring from something-with-no-contents to something-empty) which I believe has an implication of either stupidity or intent. It is hard to come up with an English equivalent.
It occurs to me, though, that "rolling one's eyes" is very often used to describe someone's reaction to such behaviour.
Filibustering: intentionally speaking for extremely long amounts of time to delay something (generally a political process)
Filling time: intentionally doing or saying things that are useless or irrelevant to take up time.
Waffling: Using far more words than necessary to make a point, sometimes no point at all.
Bullshitting: making such a long and elaborate argument that people might be convinced about one of following:
Carrying on about <topic>: when someone is speaking at length about something and is very hard to politely interrupt.
Spouting nonsense: When much of what someone is saying is obviously untrue, contradictory, or don't make sense. Usually unintentional.
Talking in circles: describes a speaker who says a lot of words but keeps saying the same thing in different ways, and never quite making a convincing point. This can be intentional or not.
Busy work: doing work to convince others, or even oneself, that one is being productive. This can be carrying blank paper between desks or pretending to make phone calls, or "actual" work like assigning a group to research and write a 200 page report that is of no use to anybody.
This reminds me of an idiom that hasn't been mentioned yet: You can't get blood from a stone.
From phrases.com:
As we all know we cannot get blood out of stone as it doesn’t have any. Similarly, we cannot get the impossible and hopeless things. You cannot ask for mercy from a hard-hearted person, you cannot borrow money from a poor man.
It also says this:
Similar idiom, “from nothing comes nothing” was used by a Greek philosopher Xenophanes in the 500 B.C. Another great British writer Charles Dickson liked this saying the most and hence used in his books in the mid 19th century.
If the original phrase is intended to be derogatory towards an individual:
"That Piotr, what an idiot, talk about trying to fill an empty bucket with an empty jug".
It is then just an insult I suppose, if you wanted an English equivalent, two of my personal favourites to describe someone's lack of skill/effort/common sense are:
"That Piotr, what an idiot, he's as much use as a chocolate teapot", "That Piotr, what an idiot, he's as much use as tits on a fish"
