INTP live in their heads and are too afraid to excercise their ideas. They prefer to keep the ideas in their brain and indulge in abstract thought because they fear uncertainy. Thats why they make good professors and intellectual eggheads in academia.
ENTP experiment with ideas and would gladly suffer the consequences. they want turn idea into action and become something tangible in reality. Sometimes the consequence could be as devastating as losing their entire fortune or taking part in a sucidal venture. But ENTP don't care because they can live with the failure. They rather do it than entertain the idea in their head. ENTP are also less cautious and can seem reckless at times. They don't overanalyze like the INTP and are less intelligent than their introverted brothers. ENTP experiments tend to be out of control and scary for more cautious types (like ISTJ).
The fear of poverty turns people into slaves of money.
"In this Caesar there are many Mariuses"~Sulla
Conquer your inner demons first before you conquer the world.
I really like your exposition on introversion versus extroversion. Personally, I've struggled with whether or not I'm an INTP because I develop anxiety when I feel overwhelmed with stimuli at parties, ceremonies, et al. As far as I can ascertain, INTPs and ENTPs are socially indistinguishable in situations where they feel comfortable. Well, the ENTP is probably a tad more obnoxious.
I was watching the fourth Pirates of the Caribbean movie a few days ago. I'm certain Jack Sparrow - my bad, Captain Jack Sparrow - is an ENTP and Barbossa is INTP. Now, there was a scene where they were going into a Spanish camp to steal some cups. Barbossa asks Sparrow "What's the plan?" and Sparrow doesn't know what Barbossa is talking about. Barbossa is stupefied and asks something like "Isn't that what you usually do? make a plan?" Sparrow says that they'll improvise, and Barbossa doesn't look too trustful of Sparrow's "plan".
Great men are like eagles, and build their nest on some lofty solitude.