“I can live well alone!” is not correct. If I live alone, I can survive to some extent, but ultimately, it is hard to survive, and “living well” is even more challenging. This is because the economic principle is established not by ‘alone’ but by ‘many people.’ If I live well, it means that someone has become poor because of me or is living well with me. The fact that through value exchange, or transaction, we can meet each other’s needs and store the surplus from that production is both true and real. Trading is not done in isolation. - Joseph’s “just my thoughts”
"Apples are the fruit" is a true proposition. At this time, "apples" are a Sufficient Condition to be fruit, and vice versa, because the "fruit to be an apple is more necessary for other conditions such as "red, round", the fruit is a Necessary Condition to become an apple. If the proposition of "If you respect someone, you'll get married" is "true," it's a "Sufficient Condition" to find someone you admire for marriage, but it's just only a "Necessary Condition" to find someone to marry for respect. Even with respect, you can not get married. You can't get married even if the Reverse Proposition is "true." Because marriage is a matter of "choice" before conditions or needs. If you want a respectable man, you can find a great man. To live comfortably, you can find a rich man. So, is there no Necessary-Sufficient Proposition for a marriage (conditions where both the proposition ...