I was once told not to end "firstly [point 1], secondly [point2], thirdly [point 3]" in -ly and to leave them as first, second, third etc. Is this always true or only in certain situations? Is it ever correct to use the word "firstly"?
I came accross this article where the author writes
Firstly: hogwash. (True, the oboe doesn’t have a built-in tuning slide. But an oboist can “tune” by switching reeds, and can humor individual notes sharper or flatter on the fly, just like any wind player.) Secondly: if we tune to the principal oboe because it can’t be tuned, then what is the second oboist expected to do?
Is it correct to separate the ordinal numbers into different sentences like this? Is there a specific name for the speech pattern where people are making multiple arguments to prove a point?