According to star trek, in temporal mechanics an "Effect" can come before the "Cause", making normal cause and effect analysis useless.

I believe I've found such a situation when Overflank is used. For those who don't know, Overflank is a teamwork feat that makes you get an attack of opportunity on an opponent if the person you're flanking with crits.

Say person A and person B are flanking a creature. For fun they both have 15-20 crit weapons (not necessary, but makes this example more likely). Person A attacks and crits, this causes B to get an AoO. On this AoO, B gets a crit. This causes A to get an AoO.

Now, since AoOs resolve before the attack that triggered them, Person A gets an attack of opportunity because of an attack that hasn't occurred yet.

This isn't really a big deal, I just through it was a funny situation. This actually occurred in our running of RotRL recently, causing us to do 270 nonlethal (we have merciful weapons) to a creature as a single act (one attack, several chaining AoOs). It's amazing what acrobatics and good flanking can do.

There isn't any reversal of "Cause" and "Effect".

First, because this Feat doesn't work like normal "AoO provoking events", but simply allows your ally to make an AoO because the act of hitting (and critting) the mutual target essentially makes the target themself provoke an AoO. So the AoO enabled by the Feat is happening after the Crit.

The chain of events you're trying to describe really would match more closely to a chain of events where combatant A tries to trip combatant B without having improved trip, provoking an AoO, and combatant B likewise tries to trip combatant A without improved trip, causing an AoO chain until they run out of AoO's.

Though it's true that by the rules of thumb we use in-game, AoO's resolve before "the events that trigger them", you have to think about what is it about an event that triggers an AoO that makes it do so? The basic idea is that it is something that 'lets your guard down', whether not focusing on combat or something enough outside your expertise (say, a trip) that your guard is effectively let down. So the 'chain of events' is more accurately something like: A lets Guard Down -> B takes AoO -> A completes distracting Action which necessitated them letting down their guard in the first place. Or if you don't want to separate the letting guard down and the provoking action, you could express it like: A *starts* provoking action -> B takes AoO -> A *completes* provoking action. So Cause and Effect is really just like it's always been. :-)

Starting a post out with "According to star trek" is pretty bold, though... :-)

So A starts attack -> B starts attack -> A starts attack and finishes it -> B finishes attack -> A finishes attack. All well and good, but that means that A is now doing two things at once with the same weapon (in the example both characters had only one weapon).

And "According to star trek" is the best way to start a post ;)

I will look for an official ruling when i can, but i was always under the impression that you can not take a AoO on your own turn. As I said I will look for page reference when i get a chance, but this is always the way i have played it.

You can take an AoO on your own turn if someone provokes it. For example, someone holds their action and declares they will 'flee' if their hitpoints drop below a certain point, you hit them twice in an iterative attack and their hitpoints hit the magic spot or lower. A held action that's contingent on a specific event can interrupt an action (like standing next to an open doorway and declaring an attack against anyone coming through it can interrupt someone's charge action as they are attacked mid-charge, or a set spear can attack someone even on a charge if the person is set to spear the charging person).

So, you hit twice, the person flees (flat out run away). You get an AoO as they drop the fight and flee, despite it being your turn.

Now, as to the OPs situation... I can't see why it wouldn't chain. Note that you are allowed an AoO, but you have to have one to take. If you don't have combat reflexes, that's one max.

I will look for an official ruling when i can, but i was always under the impression that you can not take a AoO on your own turn. As I said I will look for page reference when i get a chance, but this is always the way i have played it.

I just looked that up and did not see a "whose turn is it" limitation...it might be there, but i did not see it. In fact, it defines threatened squares as those squares you can attack in melee "even when it is not your turn." The even when implies that you certainly can when it is your turn...not sure that's supposed to be restricted to your regular attacks, but that's all I could find on it.

Odd that it does not specifically define it as a "free action," but does say that it is a "free attack." Of course, given the combat reflexes feat, it is certainly not a swift action (which could only be done once per round total, sans house rule).

AoO's are not "actions" in the (Full/Standard/Move/Swift/Free)sense, they are only regulated by the number of AoO's you can take per round (normally 1).
Most Free Actions can only be taken on your own turn
(Talking is usually hand-waved, though AFAIK there isn't a specific rules distinction between it and other Free Actions)

Well i couldn't find anything that supports the way my group plays. I guess it just didn't make sense to us when it came up the first time so that's the way we have always done it.

Starting a post out with "According to star trek" is pretty bold, though... :-)

Yes. he boldly went where no man has gone before.

Batts