Quote Originally Posted by poopdeville
I asked a specific question: "What is the difference between a logia and a paramecia fruit?"
Different paramecia fruits operate differently, and discussing certain paramecias' similarities to logia doesn't really answer the question. The rule Oda has used is:

Physical attacks pass through a logia user's body.
Physical attacks do not pass through a paramecia user's body.

Both paramecia and logia may be vulnerable to certain non-physical attacks that is dependent on each individual fruit.

The noted exception to this is Blackbeard, who states that his logia is different from other logia fruits because physical attacks do not pass through his body.