What is the relevance of Pratityasamutpada in Nagarjunas system? In his philosophy, Nagarjuna uses the Pratityasamutpada to prove, that everything is empty and without reality. In the end, however he proves not only the emptiness of that very Pratityasamutpada but he also somehow leaves the law (of dependent arising) intact and working. Does anyone understand his point, especially in what concerns Pratityasamutpada?
I took a university course in Asian Philosophy and my professor explained emptiness this way:

Nagarjuna makes the claim that an essence (a list of essential qualities that make a thing what it is) can only be stated in reference to other things. This is a way of saying that all things are defined in relation to other things, including samsara and nirvana.
The point of doing this, supposedly, is to help us realize that this means enlightenment and samsara are defined in terms of each other: Without samsara we can't define enlightenment, and without enlightenment we can't define samsara.

Basically according to this professor, Nagarjuna makes the argument that &quot;We're all in this together&quot; and we should be helping each other reach enlightenment and not strive for it by ourselves.
He also stated that Emptiness is a flashy re-packaging of the teaching of dependent origination.
In my opinion, the concept of Emptiness makes sense, but I don't really see how it's useful above and beyond the teachings in Early Buddhism. If anything, an enlightened person is more able to help others, so there shouldn't be a problem in striving towards enlightenment.