> because each party values the thing they are receiving more than the thing they are giving away.
We're not disagreeing. I think I could have been imprecise. It seems a lot of arguments made by economists who should know better quietly use models which which effectively ignore the "most basic assumption" or average it out, which is a nonsensical operation.
The quantity in question here is "price", not "value". Prices only exist when buyer and seller agree. You're right that values will be different, but I think you've missed the subject of the previous post.
Um... quite exactly the opposite? Very nearly the most basic assumption of all economic theory is that wealth is created through trade (which includes trading labor for a salary) because each party values the thing they are receiving more than the thing they are giving away.