One of them is pretty obvious: when two "J"s lock horns, only one of them can win. It's part of the testosterone thing that every guy (only "J"s, "P"s don't care) must try, and that establishes the pecking order, and they all recognize it. If the top dog ever shows any weakness, everybody -- or at least the #2 -- comes after him again. That's one of the reasons "J"s never apologize (for anything significant; being "sorry" that the other person has frail "hurt" feelings is a slap-down, not an apology), because apologizing is a sign of weakness, and they all say so (especially in fiction). I don't know much about this kind of testosterone showmanship -- I see it in the movies, and it never made sense to me -- but it obviously happens a lot, winner take all.
The story is different when "J"s go up against "P"s. There are two kinds (relevant to this discussion), Feelers ("F"s) who value affirmation (they call it "relationship") above all else, and Thinkers ("T"s) who value Truth, Justice, and Duty above affirmation. There are the same two kinds of "J"s, but the urge to win at all costs generally overwhelms all other considerations. Anyway, when an "FP" is attacked by a "J", the desire for affirmation compels them to go belly-up in hopes of gaining that coveted affirmation. It doesn't work, of course, but the "J" wins those battles without a scratch. Eventually the "FP" wife figures out that she's been had, and divorces the jerk. Until then she cries a lot, and the guy usually hasn't got a clue why. Or if he's an "FJ" he ladles on affirmation, which delays the end (but usually does not prevent it). The "J" guys all know about that conflict, even if they don't understand why it's their fault, not the woman's. But they have a lot of experience winning against "FP"s. "FP"s never win. They don't even try.
"TP"s are different. They value Truth, which is a winning argument in
verbal debate. They value Justice, which sometimes tends to win in physical
combat (but not against movie-style male idiots, who do all their decision-making
in their loins). And because the "TP"s care about Justice and especially
Truth, they spend a lot of effort finding out what is True and Just. Being
also "P"s, they are never satisfied with what they have, but keep revising
their understanding -- "J"s get stuck on whatever convinced them first,
then they don't want to be confused by contrary facts -- so after a short
while the "TP" almost certainly is on the side of the Truth. This makes
for really bad karma around "J"s, so "TP"s mostly stay out of their way.
The smart ones go work in a scientific lab, where their values are appreciated
and it's the lab manager's job to protect them from the "J"s higher up
the corporate ladder, and the less smart "TP"s drive trucks or dig ditches
or some other poorly-esteemed job where their scratchy personality can
be safely ignored. As a consequence, the "J"s mostly never meet the "TP"s
head-on in a fight.
If you are a "J", and you need to fight a "TP" for supremacy, this
blog post is for you. Give it up, You. Will. Lose.
You can win apart from the facts by insisting on a winner-take-all, one-time face-to-face confrontation (see "Cowardly Face-to-Face"). "TP"s take the time necessary to fully evaluate their facts and data, and this does not happen in real time except by luck. Force him into a real-time conflict, and he will freeze up like a deer in headlights, and you win. Until the next time he sees you, and then he will tell you all the ways you were wrong. Some of them, anyway, until you shout him down. After all, "J"s make up their minds early, please don't confuse them with facts. If the "TP" tries to do it anyway, the "J" will just call him a liar (probably using other words) and use that as an excuse to shut down the communication channel. I have experienced this effect myself, and it also shows up in fiction (frex, Clancy's Sum of All Fears, in my blog post yesterday).
This only works once. After he's been bludgeoned thus by a "J" bully, the "TP" knows to avoid such confrontations at all costs. The lab scientist is protected from such abuse by the lab manager (probably himself a "J" or at least knows their wiles), who handles all confrontations, with his scientists feeding him data privately. You see this in high-level government meetings and sometimes in courtrooms, where the support people whisper facts to the litigator, but never face the dragon directly. The "TP" without that protection can simulate it by preparing all his data ahead of time in a readily accessible form, so when the bully comes on with his intimidation, he has a ready answer. Against a prepared "TP" You. Will. Lose. Don't go there.
You can win on a level playing field, but only by adopting "TP" behavior patterns up-front. Spend a lot of time doing research (or get that support team of "TP"s) -- not to prove why your adopted position is right, but to evaluate whether the other position might be better. Being Right comes not from choosing sides first, but from choosing sides last, after everybody has looked at all the evidence and compared all the arguments. Do this before you enter the debate and you can win, but only if you lucked onto the Right side. The "TP" will spend more time on it than you did or want to, so he will be right in the end. If you "win" against him, it will happen in the first hour or two. After that, if he's not on the same side, You. Will. Lose. Bet on it.
There is another way to win an argument against a "TP", and that is
to pick a topic he doesn't care about. "FP"s don't care about truth at
all, so any argument against an "FP" wins by default. But all that research
the "TP"s do takes time, and there are only so many hours in the day, so
"TP"s need to choose their battles, and abandon the rest. Pick one he doesn't
want to fight, and you win. Again, it will happen in the first hour. After
that, if he's not on the same side, it means he decided it's worth fighting
for and You. Will. Lose. Bet on it.