Because of the renewed controversy over the banning of Rabbi Nosson Slifkin and his works, I thought it would be helpful to again summarize the position of Rabbi Aryeh Kaplan, z"l on the age of the universe.
Rabbi Kaplan was both an illui (genius) in Torah and an illui in physics, and was arguably the most qualified individual of the previous generation to discuss the interface of Torah and science.
PART 1: Background.
1. As long as no halakha is involved, there is no reason to paskin on (decide) an issue.
2. In his Guide to the Perplexed, the Rambam builds several shitot (philosophies) based on da'at yachid, an individual view of a sage that is not upheld by the majority. As long as this is done for hashgafah (philosophy, outlook) and not for legal issues, this is perfectly fine.
3. One cannot label an idea heretical until one has surveyed the sources. Perhaps Gedolim from earlier generations held the same view. If so, the view is not heresy.
4. Sefer Temunah, an early kabbalistic work attributed to the 1st century Tanna Nehunya ben ha-Kanah, is a work that discusses the kabbalistic import of the shapes of the Hebrew letters. Sefer Temunah is quoted in many different Halakhic sources (including the Beit Yosef) that deal with sofrut – writing Torah scrolls, mezuzot and megilot.
5. Sefer Temunah also comments on the Shmita Theory, the idea that sabbatical cycles existed before the creation of Adam, and that those cycles – those years – were actual physical years.
6. Sefer Temunah states that we are in the 6th 7,000-year sabbatical cycle and that the world is 42,000 years old.
7. The Shmita Theory became known as the Shitat Sefer Temunah.
8. Many pre-ARI kabbalists accepted the Shitat Sefer Temunah, including the Ramban, his close student Yitzhak of Akko, and the RADBAZ.
9. The Ramban's position is difficult to understand if you have not first learned Shitat Sefer Temunah.
10. The ARI (Rabbi Isaac Luria) rejected Shitat Sefer Temunah and taught that these cycles were not physical years but were instead spiritual, non-physical years. Rabbi Moshe Cordevero agreed with the ARI.
11. Because of the spread of Lurianic Kabbalah, Shitat Sefer Temunah became less and less known. For the most part, only those few scholars who studied ancient kabbalistic works were aware of it.
12. In 1838, when the Tiferet Yisrael wrote his essay on the age of the universe that advocated a universe much older than 6,000 years, his works were banned by some hasidim. Others simply ripped the essay out of the larger work.
13. The Tiferet Yisrael's 'crime' ? Not accepting the ARI's opinion as binding. (See #1, #2 and #3 above.)
PART 2: Could The World Have Been Created 'Old'?
1. No Jewish source exists to support this contention.
2. To make the world appear to be billions of years old when it is really 6000 years old is problematic:
a. It makes G-d appear to be deceptive.
b. If one accepts the idea that G-d created an 'old' world, why not say the world was created 5 minutes ago and we with it, with all of our memories, etc. ready-made?
c. Again, there is no Jewish source for this idea. [It was invented by the 19th century Christian apologist Philip Henry Gosse.]
3. One can believe it it one desires. Such a belief – even absent Jewish sources to support it – is not heresy.
PART 3: The Shita of Yitzhak of Akko.
1. He was a student and a colleague of the RAMBAN.
2. Was one of the foremost kabbalists of his time.
3. Investigated and authenticated the Zohar, which was then published in his lifetime.
4. Is often quoted in the Mussar classic, Reishit Hokhmah.
5. In his work Otzar HaHayyim, Yizhak of Acco writes that, because the sabbatical cycles referred to in Shitat Sefer Temunah existed before Adam, they must be measured in Divine years, not human years.
6. Therefore, Sefer Temunah is speaking of Divine years when it states that the world is 42,000 years old.
7. According to midrashic sources, a Divine day is 1,000 earth-years long.
8. A Divine year would therefore equal 365,250 earth years.
9. So, according to Yitzhak of Acco, the universe would be 42,000 x 365,250 earth-years old.
10. That calculation comes out to 15.3 billion years, very close to current estimates for the Big Bang.
Part 4: Conclusion.
1. There does not have to be a conflict between science and Torah on the age of the universe.
2. Pre-Ari Torah-teachings have in fact been confirmed by modern science.