There are several ways to paraphrase this sentence and I would want to know which is the best one, or rather to know which is more appropriate when talking or writing an essay / project.
-
To open / begin a discussion
-
To open / begin an argument
In addition, to know if there's a more formal way to say this.
Thanks for your help!
Best Answer
Let me list the frequency of each expression in COCA:
It's seems reasonable to me that to open an argument should not be an idiomatic collocation, unlike to start/begin an argument, because an argument doesn't exist until you start it, and therefore there's nothing to open (before it's started).
On the other hand, a discussion about a particular subject exists potentially (in the sense that there already exist some untold facts about the subject of the discussion), and therefore you can open it.
I don't have a definite idea as to why you cannot begin an argument, whereas starting an argument would be fine (take a look at this n-gram too). Surprisingly, start a fight, start a feud, etc are all acceptable collocations, but if you substitute begin for start, they turn out to be uncommon. This merits a whole other question, but maybe this synonym discussion from Merriam-Webster Dictionary could provide a clue, (where it says that start applies especially to first steps):
And to answer your final question about their formality, you can see from the discussion above that by replacing start/begin with commence you could have a more formal or bookish expression. But I personally don't see why you should do that, as there's nothing especially informal about the original expressions.
However, here'e Cambridge Dictionary stating that begin is more formal than start (only when they can be used interchangeably, of course).