In Thelema, for those who may not be aware of it, there is this concept of everyone having a True Will, which is similar to a divine path or destiny for lack of better term. It was revealed in the Book of The Law as Do what thou wilt shall be the whole of the law. The Thelemite, a follower of Thelema, constantly pursues their True Will whatever that may be. However, no one person can determine this for another and everyone may have their own unique way of finding, pursuing, and determining just what direction thier True Will is leading them in. So, we have no way of knowing if everyone is actually pursuing thier True Will or not, there's no way to be sure. What we have to hope is that the great cosmic, if even chaotic, machine of existence reveals this to us over time.
In regards to ethics, Thelema has the craziest context in which to base the definition of right and wrong. For instance, in the case of the concept of their being a True Will, that which is not in alignment with one's Will or even against it would be considered as being wrong regardless of what one's everyday society would say in regards to a particular act.
For example, stealing, regarded as being wrong in a none Thelemic world, would be right if it were to occur in a Thelemic world and were in alignment with the Will of the 'thief' (also implying that stealing and the idea of theft were still existent in a Thelemic world).
Theoretics aside, we live in the world that does conform to or reflect Thelema. Much like any minority faith tradition or philosophy, Thelema mostly exists at a personal level, which may, at times, not allow it to be easily practiced or applied to the greater world. Though, we can do anything we choose to do, we are unable to thwart the ramifications of our action by sighting our religion as an excuse or justification.
Despite having a law like the Law of Thelema, Thelemites may be unable to fulfill their Will at times due to other societal or worldly concerns. Most of us, after all, live in countries founded or based within other religious traditions and often have to find a medium ground between who we were are and the society in which we live. Regardless of our faith, our ethics more often stem more from the societies and cultures in which we were raised in and not necessarily from our faith. It would then be relevant to ask how much of our upbringing do we impose upon our faith and vice versa?