Nicht und Kein/Keine
Please help me understand when to use "nicht" and when to use "kein(e)"
A phrasebook I have say nicht is used after a verb but if a noun is used, add kein(e)
I don't understand why "Ich bin nicht Thomas" is correct and "Ich bin kein Thomas" is incorrect. Isn't "Thomas" a noun?
Thomas is not a noun as "table" or "house". It is a name.
Depending on context (and very specific ones) I'd say both are good.
A: Bist du Thomas?
B: Nein, ich bin nicht Thomas
A: "Everyone named Thomas has to get up at 5 tomorrow"
B: Gott sei Dank, ich bin kein Thomas
I'm not 100% sure though. That's what my gut says as a non-native speaker
I am not a native speaker either, but I do feel confident enough to say your distinction is right. :)
Another example: Ist Thomas hier?
- Nein, Thomas ist nicht hier (The person called Thomas (and I probably know who you mean) is somewhere, but not here)
- Nein, hier ist kein Thomas (There is nobody called Thomas here and I probably don't know who you mean)
To elaborate a bit: The distinction for "nicht" vs "kein" is more about whether it's definite (refers to one specific instance) or indefinite (refers to all of them). For example, "Das ist kein Haus" (That is not a house - it's something, but it doesn't belong to the category of things we would call a house) vs "Das ist nicht das Haus, das ich kaufen will" (That's not the house that I want to buy - it is a house, but not the specific one I mean). Proper nouns (like people's names) usually use "nicht" because they usually refer to a specific person.
"kein" (when singular) is like "not a" in English. You wouldn't normally say "Ich bin kein Thomas" in the same way that you wouldn't normally say "I am not a Thomas".
Kein(e) means "not a" So you would use it to translate "That is not a book" or "I do not have a book." You use it before common nouns. Or in other words, you use it before nouns that take an article. You would not normally use kein(e) before Thomas because Thomas is a proper noun not a common noun. We do not usually use articles before proper nouns. In English, you would say "That is not Thomas" but you wouldn't normally say, "That is not a Thomas." So before Thomas, in German, we would use nicht not kein(e).
The way I learned it in high school was, "Don't use kein(e) where you wouldn't use ein(e)."
So if you wouldn't say "I am a Thomas" ("Ich bin ein Thomas"), don't say "I am no Thomas" ("Ich bin kein Thomas").
Fortunately this is one of those areas where English and German articles correspond. :)
as 'kein/keine' can translate as 'not a', I believe saying 'ich bin kein Thomas' would mean 'I am not a thomas'