ALL texts from Indo-Iranian culture are of interest to understand how they viewed the world (and I'm an in-between in regards to Gathas and Avesta just like yourself, Bahman!). Also, all other traces are most helpful. We must also understand that Indo-Europeans in Europe and Indo-Iranians in Iran and India are all of the same origin and therefore likely to share worldviews in many instances, far more so than with people of other origins in Eurasia. This is why Parviz is correct to point out that "amordad" means "death defiance" and not "immortality". The concept of immortality did not exist in ANY Indo-European cultures as understood later in semitic and Greek culture. Another word for "death defiance" is "transcendence" meaning "that which transcends or seems to transcend physical reality". Quite a difference then from immortality!
2009/10/7 Bahman Noruziaan
Referring to your comment:
"To understand the ancient Iranians, we must FIRST understand HOW they VIEWED the world. Their worldview was radically different from ours. Only THEN we can begin to understand what they mean.",
I suppose that you agree the best and perhaps the only reliable source is Avesta, including all its various books, such as Yashts, Yasnas, Visperad, Vandidad, and so on.
Also referring to:
"So when Zarathushtra speaks of "soul" or "body" he does not even discuss OPPOSITES the way we have been trained to see them. To him and his culture, these are just ATTRIBUTES of one and the same thing, Ahura!"
The same idea flows into later, Zoroastrian tradition, where Manioo and Gaiti are both manifestation of the same unity, distinct but from the same source and so one in essence. There is Manioo in all elements of Gaiti. Referring to "Khorshid Niyayesh" as well as "Mehr Niayesh" and other Niyayesh prayers, a Zoroastrian praises the Mainoo of the sun, the moon and so on, in addition to praising their material benefits for the world. All universe in Zoroastrian tradition is sacred and worthy of veneration.
This idea that the whole existence is one and there is unity between material and spiritual, flows into Iranian philosophy, centuries after the passing of Ashoo Zarathushtra. The term "Vahdat-e Vojoud" composed of two Arabic words and and meaning unity of existence refers to the same idea.
This is based on my limited reading and knowledge.