The guy you give the paper to could read your mind.
There would be people who are unreadable. Maybe they have too much noise in their heads. Maybe they have trained themselves to be “obtuse”. Maybe their brain waves are just really eccentric, coded in a language that few can understand. Regardless of the reason, they would be unreadable.
If this group comprises just a minority, they will be discriminated against. Their trustworthiness would come into question. They would be pathologized by the medically oriented and vilified by the spiritually-minded. They would feel alienated and lonely, constantly bombarded by all the bad thoughts everyone has about them.
There would also be people who can’t “read”. They would be handicapped, but they’d probably be able to hide it with enough cleverness.
It wouldn’t take long for people to subvert the system. They would invent “brain wave scrambler” devices, or they’d train themselves to mask their thoughts.
So everything would work out.
Crime and corruption would plummet. It may take a little while for the legal systems of the world to cope with the new forms of evidence, but in the meantime, officer testimony has never been so reliable and trustworthy!
Waste and loss would decrease significantly in innumerable fields of endeavors. Overall productivity would likely increase as a result.
Some occupations would wither away and die, others would transform (used car salesmen become trusted experts at matching a customer’s needs and budgets to available cars). New occupations would spring up - independent reputation verification firms, staffed by persons of proven integrity located around the world who vouch for various long-distance transactions and the like.
Sealing deals via handshakes would become vogue again.
Clinical therapists would either evaporate as a profession, or become vastly more effective than ever. I’m not sure which way that would go.
Many neuroses and anxieties would quickly vanish. Worried that everyone can read your mind and tell that you get boners all the time (especially good for adolescents)? Just find some bloke who doesn’t give a damn what hysterical prudes think about his junk.* How does he do that?* One brief look, and you can adopt that mindset for yourself. The concept of “memes” would regain their original meaning (no longer referring to Bad Luck Brian pictures/text), and people would be on the lookout for useful memes to adopt for themselves.
Early days would be difficult, yes, but there’s always been a strong market for various self-help books and X for Dummies-type things. Very shortly, there would be a whole range of materials on how to cope with Y2K, er, I mean, how to cope with the new telepathic society. And at least some of these How-to guides would at least have the benefit of having some actual telepathic insight as to whether or not they work.
Many marriages would fail. Others would become stronger. Yes, they had an affair, but you can now know with certainty that they still love you and are sorry that you were hurt by this. A lot of people will find themselves growing up and getting over themselves, very quickly.
What happens to religion, and other ideologies, would be very interesting to see. I’m sure the devout believers would be certain that there will be many conversions in their religion’s favor. I’m sure the more moderate, secular types would believe the converse to be true. As for the various hardcore fundamentalists authoritarian types (cult leaders, etc)… I predict that the vast majority of them would fail quickly and hard. Societal mores would definitely shift in a variety of ways, regardless, and I think that would be most fascinating to see.
My question, and perhaps one day I’ll make a thread about it: There already are effective telepaths in significant numbers. Explain both how they remain “underground”, and also how the world functions as it does when the presence of such people should have a great impact on, well, all the things people are mentioning in this thread.
How do we define ‘thoughts’?
Are these just the normal surface thoughts, the sub-vocalized thoughts, or are they somehow deeper?
Nope.
But how would such a thing deal with passing thoughts, as opposed to deeply held beliefs?
How many of you can honestly say that there are not moments when you could happily murder someone? What would happen to such thoughts?
For the first like 20 or 30 years, this is pretty much what would happen:
"Oh my god! Oh my god! You people are sick, sick, sick little monkeys!
WHAT IS WRONG WITH YOU???
That’s not even how you ***use ***salad dressing! :smack:"
Soon, the internet is abolished, and everyone is required to play pazaak in their head to protect the world from their filthy thoughts.
[/Obscure KOTOR2 reference.]
I think people would become nicer (if they couldn’t beat it with a tech fix / some sort of blocking trick).
You can train your thoughts. It isn’t easy, but there would be a big incentive to continue trying to be a better person. Plus, if you were sincere even in the ‘training phase’ people would ‘hear’ you self-correcting your thoughts. Of course, they’d also ‘hear’ it if you weren’t and were just doing it because you were ‘supposed to’.
Mind you, I’d be fired the first time I had to attend a work meeting! 
A lot of competitive games would wither and die, or else be played exclusively over secured Internet connections.
On a more serious note, my guess is that people make snap judgments and have unflattering reactions to strangers all the time, many times automatically. How would people react if they passed by someone they’d never met, and they KNEW that person was thinking about how ugly their clothes were, or how hideous and ill-mannered their child was?
I know this is your hypothetical and you can write the rules, but I think this is an unrealistic condition. Telepathy would be just another sense. Any sense can malfunction.
Can you think of a sense that every single person has?
The world would became a bit disgusted with itself as we came to the realization that some of the people we deem as “sick” or “deviant” are not as far from the norm as we would like to think.
A lot like ourselves, in fact.
Aloha
If as Czarcasm says, it started up suddenly at midnight last night, how long would it take for everyone to admit that they could read other’s minds? Also, would we realize when our minds were being read by someone else?
I’m just wondering when it would actually click that I could read minds; I don’t go around thinking “I wish I could read that person’s mind.”
Also, if someone came up to me and said “Hey! Did you know I can read minds now?” I’d think they were insane, but might give it a shot. Then I’d wonder if I was crazy, or if it was just the two of us that could read minds, or how exactly all this works.
People would still deny that mind-read information would be true; there’d be a long period of “Mind reading is BS; you can’t prove that I did/thought/said that.” even though you did read it.
I also suspect we’d suffer from a lot of unreliable narrator type stuff; I’ve known plenty of people who were present at various events, and who remember them very differently than I do.
I’m sorry-I introduce telepathy into a hypothetical, and you think the “everybody has it” aspect is the unrealistic part?
I suspect children would tell a lie (as they do), but then learn that it doesn’t work.
I think the dynamics at pick-up bars would drastically change-you walk in, and know instantly if you have a chance with anybody.
Football coaches would have to drop all their elaborate plays and depend more on the talents of the individual players.
Schools might be a problem.
Sounds like hell to me. Lets all live in transparent houses while we’re at it. And Cc the government on all our personal emails… wait, that’s another thread.
Nonsense.
It’s somewhat contradictory to say you have to be able to see the person to use it, but it can’t be blocked. Because it can be blocked by making sure no one can see you. People would start going around in chador and veils, or space suits, or leather coveralls and boots and gloves and helmets, or scuba gear, or whatever other complete coverings they could figure out. People (at least, most adults) would only let themselves be seen when they wanted to test the waters of trust. It would not be a matter of having something to hide that you were ashamed of, or at least that would be the civil, polite fiction - it would be a matter of hiding your inopportune rudeness, your incivil thoughts, and of course your professional secrets - passwords, health of others, that sort of thing that you are obliged not to reveal. As well as confidences of your own intimates whose thoughts you, by now, know.
Some younger people (teens and some younger adults) would defiantly bare themselves to the world, feeling they had no secrets worth keeping. A romantic attitude, albeit often unrealistic.
First off, huge spike in the homicide rate worldwide. Slightly smaller spike in the suicide rate. Domestic violence goes through the roof.
Over the next few weeks, the national security of every nation on earth is thoroughly violated. Several wars break out, both as a result of secrets learned, and as a result of national governments not bing able adapt to the new paradigm and panicking. I expect military hierarchies to be as slow to adapt as the civilian governments, and history shows that using old tactics in new kinds of war leads to horrific slaughter. A wildcard here is how a normal human psyche reacts to reading the mind of a person they’re killing. You could make a plausible argument for anything from total catatonia to raving mania, but whatever it is, it can’t be healthy.
At some point, it goes nuclear. Not Road Warrior nuclear, but several major population centers are wiped out. The psychic effects of annihilating several millions telepaths in an instant is another wild card.
The infrastructure of society starts to breakdown. There are food riots globally. Global warming continues apace, possibly accelerated, and our ability to deal with its effects are severely hampered. Famine and flood take their toll. All told, maybe two to three billion deaths. Humanity is left a traumatized wreck, huddled in the shadows of their ruined cities.
Their children, however, are going to be fucking brilliant.