I've been thinking about a thought experiment and wanted your opinion, thoughts, or input.
Introduction
Say the earth had just one man living in it, who has no exposure to other human beings.
Then for this human being, does ethics exist?
If you say it does not exist, then you are of the opinion that ethics must be a social construct.
If you say it does exist, then you are of the opinion that ethics is constructed from the individual.
I think the obvious conclusion (without going into further details) is that ethics does not exist in this case, and I think perhaps most people would generally agree.
The Question
Given the above thought experiment, how is it that some people claim that ethics is always "relative"? and that ethics is something that each person should construct for themselves?
Thank you for your time