Lindsay asked:

Can you tell me of a philosopher who contemplated on the existence of good vs. evil? Specifically, I'm
wanting to know which of them concluded that good and evil are dual qualities of our God, that both
are necessary elements that He had to construct for our existence here on Earth. That happens to be
my position, but would love to read a "professional's" position on this.

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Let me point to one thinker who is a bit "out of the way": Peter Abelard, who acquired historical fame
as a lover rather than a philosopher (cf. Abelard and Heloise). But you may need to look under
"Theology" to find his book Dialectica.As far as I'm aware, Abelard was the first of the medieval
philosopher to come out with an explicit contention as in your question.

Jürgen Lawrenz

Sydney

There are two views, which you may be confusing:

1. The standard response to the problem of evil (the problem of how an omnibenevolent, omniciscient
and omnipotent God would allow the existence of natural and moral evils) which is to say that the
existence of evil in the world is conducive to a greater good.

2. The Manichean (Manichaean) Heresy — for which many a medieval scholar was burned at the
stake — which holds that evil exists because God's power is insufficient to overcome the power of the
Devil, who is responsible for the existence of evil.

Geoffrey Klempner

I do not know whether the sages and thinkers of ancient Persia (Iran), including Zarathoustra or
Zoroaster, who contemplated and thought persistently on the existence of good vs evil could be
called "professionals". However it is interesting to observe that the dualistic Mazdean tradition of
Ohrmazd (Good) and Ahriman (Evil) contrast with the monistic thought of Zervanism or Zurvanism.
According to Zervanism, from Zervan or Zurvan (Time — the unitary principle of God) emerge both
Ohrmazd and Ahriman.

It is said that Zervanism was a major Zoroastrian heresy. R.C. Zaehner, in his book Zurvan; A
Zoroastrian DilemmaClarendon Press, Oxford 1955, supposes that it was a result of Babylonian
influences which appeared towards the end of Achaemenid empire. It was perhaps the dominant
tradition at the court of Sasanians (224—c 642 CE), the dynasty that ruled Persia until overthrown by
the Arabs.

You may also read Mary Boyce's book, Zoroastrians: Their Religious Beliefs and Practices
(Routledge and Kegan Paul, London 1979).

Jean Nakos