This depends on the topic. If the terms used are clear and the arguments used are verifiable then the person can still be wrong. He should be capable of taking a step back and objectively going over his argument and possibly admit he was wrong. That doesn’t require a second person.
If it is a matter of moral judgement…then depending on the moral system used the person can (or cannot) be right/wrong though in many systems this dichotomy doesn’t work too well.
In a matter of taste…no…the person cannot be wrong unless he is wilfully lying about his own taste or (perhaps) if his senses are temporarily malfunctioning.
In terms of arguing over unverifiable arguments…I can’t see how that person could be right even if they were arguing with someone in person.
Try a zen style question: If he is arguing with himself…can he be wrong?
As per right/wrong being rooted in community consensus…that is true to the extent of defining terms and agreeing on the mode and/or rigour of scientific-method/critical-thinking. If two different societies are both being as objective as possible and agree on a right/wrong paradigm through testing and verification…they won’t be so far off from one another.
As for taste…yes…if you must insist that taste can be right or wrong (even though it cannot) then for sure…community consensus is essential. Same with many moral systems.
If a person speaks their mind in a forest and no one is around to hear them, are they still wrong?
If the person in the forest thinks the words they have just spoken are wrong, then the person in the forest is wrong.
The inverse is true as well.
I on the other hand am always right and everyone else is always wrong. 🙂
Can you define wrong, in this context? Are we specifying the nature of the statement? For example, “Grass is green” would be open to debate, particularly if a person is color blind (I am SO fucked off with autocorrect removing my ‘u’ from every second word – colour just dropped the u)
However, the statement “Grass looks green to me” is less arguable.
Consequently there are some statements that are not in need of validation, and others that may be.