Anyone evn the person standing next to you could be a scammer. He could be nice then backstab you. Your closest friends could only be there for you because they pity you or like that you're rich. In this society nobody is who they say they are, so you can never trust anyone.
Trusting nobody means you'll not accept opportunities that may arise if trust was involved/needed. Risk taking can lead to better jobs, better lives and trust is just another type of risk taking.
Everyone makes risks by trusting people and telling others they should not trust anyone is basically telling them to not take risks in life.
It's sad, but I agree with this saying. The world today has gotten so full of scammers, thieves, and assorted criminals that you really can't trust anyone. You have to go with the assumption that everyone you don't know well is probably going to try to rip you off at some point.
Yes, the saying trust no one has merit, because there is no person who would not lie, cheat, or steal if it really came down to it. There are times that people are good. But if given enough incentive or given enough to be gained, anyone will cheat their neighbor or their brother.
The issue dealing with the saying trust no one must have merit for certain things but, not all things. Also this topic at hand it may deal with the person along with the exact issue that we are talking about. However, we should not always look so negatively at things.
I believe the saying "trust no one" does have merit. In my experience in the workforce, I never found a peer or manager or business owner that I would afford my trust to. Everyone in this world seems deceptive and self seeking. Opportunities are minimal unless you're willing to use people. I don't like stepping on people, but I don't want other people stepping on me either.
What do I mean by trust as a spectrum? Well it's simple if you think of concepts on a scale or a ruler. Don't take this too literally of course. The size of the ruler varies from person to person. (The size of the ruler is in relation to how much a person can trust another. So a person who would trust a person with their lives is way more trusting than someone who wouldn't.) For example a child will in most circumstances "at first" trust their parents 100%. But as your parents fail your expectations this number will usually change as life goes on. Some events will increase your trust in others and others deminish it. There are some people who you will trust less than others but there is always a certain degree of trust. So for example, you may not trust a random person on the street with your wallet but you may trust them enough to give you directions. If you were to trust no one "at all" then even the simple task of buying a candy bar would be impossible. You trust literally everyone and everything in one form or another.
I would argue that a state where no one can be trusted is possible but not tenable.
What I mean by that is if a closed society falls into a state of corruption severe enough to warrant a state where no one can trust anyone, then that state cannot last and would be doomed to end in a last man standing scenario.
In terms of how I would define a closed society, I would say that by definition it would have to mean the population of the Earth.
I find it strange that people will argue that mankind is essentially good but cannot argue that there is ANYONE in the world that can be trusted. Granted, bad people exist but there are close friends, neighbors, family members, and other members of your life that you SHOULD trust if you want to live a healthy lifestyle. Unfortunately, you can have your heart broken by these people but, if everyone was like that, life wouldn't be worth living anyway.