SRD Talk:Incorporeal Subtype

Interaction with physical matter?

Maybe I'm missing the obvious, but can an incorporeal creature touch physical objects or creatures (such as opening a door or punching a foe) by their touch alone (without using special powers, abilities, spells, etc.)? I ask because I didn't feel as though it was very clearly defined in the description. Please allow me to reference the points of ambiguity resulting in my confusion.

1) "An incorporeal creature can enter or pass through solid objects, but must remain adjacent to the object’s exterior, and so cannot pass entirely through an object whose space is larger than its own."

This seems to indicate that they are still in some way tied to the physical realm, as their actions are limited by their physical environment. So, while they cannot pass through a solid door, could they simply turn the knob and open it?

2) "An incorporeal creature’s attacks pass through (ignore) natural armor, armor, and shields..." [I'm not concerned with magic, etc. here. They covered that well.] and "Incorporeal creatures cannot make trip or grapple attacks, nor can they be tripped or grappled. In fact, they cannot take any physical action that would move or manipulate an opponent..."

So, they can attack, ignoring armor. But must that be a special attack (magic, psionic, etc.), or can an incorporeal creature actually strike at an opponent with a fist? But if they can't trip or grapple a foe, then how could they punch one? What if their unarmed strike counts as a magical attack?

Full disclosure: I'm considering this both for a character of my own, and possibly to use for an NPC in a campaign I want to run.

I'd appreciate it if anybody could offer any insight or answers on this.