Rabbi Moshe Sternbuch, a 'gadol' of note, has declared almost every Torah-observant Jew who believes the world is older than 6000 years to be a heretic: [Hat tip: Bnei Levi.]
Our faith is based on the traditions that have been passed down through the generations. The Rambam (Foundations of the Torah 8:1) states that the validity of our faith is not because of miraculous signs. Rather it has been validated by the fact that the Jewish people witnessed the awesome events of the Revelation of Sinai with their own eyes and ears. The Rambam (Foundations of Torah 9) goes into detail concerning this matter. Furthermore the Rambam (Laws of Disobedience 2:2) states that even a custom which has been accepted by the Jewish people under the guidance of the sages — should be considered equivalent to a ruling of the Sanhedrin itself. This is true even if the custom doesn’t have a clear origin. Therefore a person who violates such an accepted custom violates the Torah prohibition of not disobeying the rulings of the Sanhedrin. If a mere custom is viewed as equivalent to an explicit ruling of the Sanhedrin and therefore can not be rejected, then surely the accepted view of the age universe can not be disregarded. This required acceptance of the traditional age of the universe is all the more obvious since every man and woman and child knows that the world was created 5765 years ago. An additional reason why we must accept the traditional age of the universe is that the calendar system is based on this fact. [I believe this is an error. The calendar system is not based on that calculation.–editor.] Consequently a person who casts doubts on this accepted tradition — even if he is widely respected person by the Jewish people — must be carefully investigated. This is because is possible that he might have doubts concerning the foundation principles of faith — like the academic scholars.
It has already become established by the rulings of the great rabbis throughout the generations, that if a person has doubts concerning faith — he is to be considered as a non-believer. That is the halacha.…
Let me return to where we started. I do not know whether all those who accept the view of the scientists — that the world is very ancient — are heretics. However I do know that only heretics have such views against our Sages — who are fully accepted by us. I want to note in addition that those who accept that the world is ancient, also prefer to hear and accept the words of the scientists. Furthermore these people mistakenly think they have found support for their views amongst our traditional sources. In fact, however, we are obligated to always give precedent to Daas Torah. These are the accepted mainstream Torah views expressed in the Talmud as well as the writings of the great rabbis through the ages. Only those views which have been widely accepted are valid – and not minority views that have been rejected or ignored. Only after we fully accept the Torah understanding of an issue, can we consider the words of the scientists and accept that which is compatible with the words of our sages.
Furthermore having scientific writings in your house, that are incompatible with the Torah, violates the prohibition (Deuteronomy 4:26): “Do not bring disgusting things in your house.” Simple calculations from the Bible concerning the generations from Adam lead to the clear conclusion that the world is less than 6,000 years old.
Having such heretical scientific books in the home causes much troubles to those who possess themand it is obligated to get rid of them.
Furthermore the author of such unacceptable scientific writings must retract such views and subordinate himself to the authority of contemporary rabbinical authorities — according to what has been traditionally accepted.
G-d willing, I hope to offer an expanded explanation of these issues when I publish the
fourth volume of my work, “Know What to Reply.” [i.e., to the heretic.– editor.] G-d should help that His promise will be fulfilled (Zechariah 14:9), “G-d will be the King over the entire world. On that day G-d will be one and His name one.” Amen!
This would make anyone accepting the views of the Tanna Nehunia ben HaKaneh, z"l, the Rishon Yitzhak mi Akko, z"l, Rabbi Shimshon Rafael Hirsch,z"l, Rabbi Aryeh Kaplan, z"l, Rabbi Yaakov Weinberg, z"l, Rabbi Aryeh Carmel, shlit"a, Rabbi Ari Kahn, shlit"a, and many more, a heretic, and would make all living rabbis who espouse these views and do not retract heretics.
Rabbi Sternbuch also displays an understanding of science easily surpassed by the average 10 year old (non-Haredi) child.
Here is the 'gadol's' letter in PDF format: