R' Greenberg, in various articles and in a recent book, FOR THE SAKE OF HEAVEN AND EARTH:
The New Encounter Between Judaism and Christianity, expresses a theology that seems close to Reconstructionism or to classical Epicureanism (from which the word Apikoros).
Each major destruction in our history has signaled a change, a distancing, in our relationship with God. The first Destruction, in which the Ark was lost/hidden, brought an end to God's revealed presence in the world. God had hitherto interacted with us directly, through prophecy, through the Divine fire that accepted the sacrifices, through open miracles. These came to an end during the first 70-year exile.
The second Destruction removed the Temple as the focus of Judaism, the sacrificial service as a Divinely-ordained means of achieving atonement. Divine worship, and receiving atonement for one's sins, become entirely an individual responsibility, as teshuvah and tefillah became the real paths towards personal salvation, and ultimately towards the communal salvation through the Moshiach.
The Destruction of European Jewry indicated a third distancing. If the first was removal of God's direct influence, and the second removed our direct Torah-mandated path of communication to God (the Temple service), the third Destruction indicated the end of the Covenant. In allowing the Holocaust to happen, God signaled that He had abrogated His covenant with us, and the mitzvot were no longer binding.
As reviewer Michael Kress states, "In trying to answer that fundamental theodicy question—how to reconcile the idea of a just God and the flames of Auschwitz—Greenberg concludes that we have passed from a stage in which Jews are commanded to one in which the covenant with God is voluntary. God has undergone a further tzimtzum, or self limitation, which God first undertook to enact Creation, giving humans full responsibility for perfecting the world, without any divine intervention." See the full review.
In light of this view, R' Greenberg is amazed and pleased that the Jews have voluntarily continued to observe the mitzvot, given that they can't expect God to respond to them.
This leads to some disturbing questions, though:
- is it true, as a Christian preacher claimed in the last century, that God no longer hears the prayers of the Jews?
- If God has restricted/constricted Himself away from the world, does he no longer care about what happens in the world?
That would seem to be R' Greenberg's point, most like Reconstructionism or like Maimonides' definition of Epicureanism: "[Laws of Repentance 3:8] 8) There are three types of heretic [Apikorsim]: One who says that there is no Prophecy at all and that there is no knowledge given by God to men; one who refutes the Prophecy of Moses; and one who says that God doesn't know the actions of men."
Note that expressing such sentiments need not separate one from Orthodoxy. R' Mordechai Kaplan, founder of Reconstructionism and shaper of much of Conservative Jewish theology in the last century, was employed by Orthodox synagogues, and spoke at Orthodox functions, for years after he began to publish his heterodox ideas. He begain to write articles on these ideas starting around 1909, but he was not forced out of his rabbinic position in an Orthodox synagogue until 1922.