I've been looking at the Oxford Dictionary's page on inverted commas, and see that they use this example:
He called this phenomenon "the memory of water."
This seems like it would work with or without the quotation marks, but I can't seem to find any specific guidance on the appropriate use of quotation marks for sentences that say something is called something. I've written some example sentences:
I call this 'the XYZ theory'.
I have a problem with a thing called 'small talk'.
Is it a case of quotation mark/inverted comma usage being appropriate when it's an unknown term, but inappropriate when it's a commonly used noun? The first example looks correct to me, whereas the second doesn't sit right unless the quotation marks are being used to draw emphasis.
I believe that you definitely wouldn't use them with proper nouns (my friend is called Peter, not my friend is called 'Peter'), and you could use them with film/book titles, etc. But what about nouns other than those?
I'm aware this may be a duplicate to this question, but the answers seem inconclusive.