Can "neither do I" apply to both disagreement with positive statement and agreement with negative statement?

Question

I received these answers from ChatGPT and am unsure if they are accurate.

Me: how to express agreement and disagreement to positive statement and negative statement?
ChatGPT:
Agreement with positive statement:

• "Me too."
• "So do I."
• "I agree."
• "I feel the same way."
• "I also [verb]."

Disagreement with positive statement:

• "I don't either."
• "Neither do I."
• "I disagree."
• "I don't [verb]."

Agreement with negative statement:

• "Me neither."
• "Neither do I."
• "I agree."
• "I feel the same way."
• "I also don't [verb]."

Disagreement with negative statement:

• "I do."
• "I disagree."
• "I like it."
• "I [verb]."

Note that these phrases are not exhaustive and there may be other ways to express agreement or disagreement. It is also worth noting that tone and context can greatly impact the interpretation of these phrases.

Me: why can "neither do I" apply to expressing both disagreement with positive statement and agreement with negative statement?

ChatGPT: "Neither do I" can be used to express both disagreement with a positive statement and agreement with a negative statement because the phrase is meant to indicate the absence of something.

In the case of disagreement with a positive statement, the speaker is indicating that they do not share the same experience or opinion as the person they are responding to. In the case of agreement with a negative statement, the speaker is indicating that they also do not have the experience or opinion that the person they are responding to has stated.

In both cases, the phrase "neither do I" is used to convey the absence or negation of a particular experience or opinion. This is why it can be used to express agreement or disagreement depending on the statement being made.

I believe the last reply appears incorrect. Can someone kindly inform me if there are errors in ChatGPT's responses?

Answer 1

You're right. The bot is wrong.

It is always incorrect to respond to a positive statement with "Neither do I", so it has no meaning, and so cannot show agreement:

A: I like golfing.
B: Neither do I.

"Neither do I" can be used to agree with someone, but that's a very narrow view of what it can do. It roughly means, "That statement equally applies to me", so it can be used to agree with someone if that person's negative statement expresses their opinion:

A: I don't like soccer.
B: Neither do I.

But it can also apply to someone else's opinion:

A: My sister doesn't like soccer. B: Neither do I.

In this case, B isn't agreeing with A because A hasn't given any opinion.

And the expression also applies to negative statements that aren't opinions at all:

A: My cousin doesn't have a job. B: Neither do I.

Answer 2

It depends on what you mean by 'negative' and 'positive'.

As I'm sure you know, 'neither' means 'not either', so it can only ever be used to 'agree' with a previously made negative statement - negative in the sense of using a negation.

Of course, 'negative' can also mean that the overall meaning or message of your language is unpleasant, unwanted, disappointing, hurtful etc.

A negation (like 'not') is simply used to reverse the meaning of something, which means you can use a negation but still send a 'positive' message - positive in the sense of having something to say that is pleasant, welcome, upbuilding etc. For example, we commonly say "not bad" to mean that something is quite good, and "not good" to say that something is bad, or at least mediocre.

So, 'neither' as a response would always follow a negation, but if the original statement with the negation is positive in tone or message then the reply that agrees with it is also positive.

-I can't (negation) believe we won the lottery!
-Me neither! (I cannot believe it either!)