TWF with Natural Weapons?

[WerePox47]

Ok so ive heard/read some on this subject and i just wanted clarification. Lets say for example i wanted to play a ninja/monk combo, but take an archetype that takes away FOB. Now lets say i take TWF and Imp. TWF as feats. Can i attack with imp. unarmed strike and make 2 mainhand and 2 offhand attacks? FOB states that it wokrs like TWF, so i assume u can, afterall it doesnt make much sense to me why u could make 4 attacks with say short swords and not drop said short swords and make 4 attacks with ur bare fists. Have i dreamt up this idea that u can only make 1 natural attack with each hand unless ur a monk? Please help me clarify this and if so help me to understand why a hand holding a sword is diff from a hand not holding a sword, but is instead balled up...

[blackbloodtroll]

Bestiary has the correct rules for natural attacks.

Natural attacks do not use the two weapon fighting rules at all.

[WerePox47]

Ok so the way i read it umarmed strikes may take advantage of TWF, but natural attacks are limited to the number of limbs u have capable of making an attack. So is a punch an unarmed strike or a natural attack? lol... Additionally do humans automatically get 4 natural attacks due to 2 arms and 2 legs capable of making such attacks? Why is this so dam confusing...

[blackbloodtroll]

An unarmed strike is one weapon.

[pobbes]

Unarmed strikes from IUS act as manufactured weapons. They still act as natural weapons since they are attached to the PC. So, use the TWF rules as if your unarmed strikes were short swords.
Natural weapons are a separate beast anyway and most PC races have zero. To make it even easier, the core rules did not have a way for PCs to have natural weapons, and they were not expected to understood the nuances except for mounts and animal companions who couldn't use weapons. So, PCs generally use manufactured weapons rules, and creatures use natural weapon rules. So, things that come from feats or class levels, like IUS work as a manufactured weapon.
It was later supplements that started mixing the two in confusing ways.