Why do we celebrate Chanukah for eight days? Here's the explanation provided by the Talmud:

After recovering the Temple from the Greeks, the Maccabees set up a makeshift Menorah. The Menorah in the Temple is meant to be lit every day a short while before sunset, and stay lit until the next day.

Miraculously, the Maccabees were able to find one flask of pure olive oil, sealed with the seal of the High Priest, undefiled by the Greeks. But that flask contained only enough oil to burn for one night and day—and it would take them seven days to procure new pure olive oil.

Miraculously, the oil burned for eight days. So we celebrate for eight days.

But wait, how does that explain things? If there was enough oil to burn for one day, and the oil burned for seven days longer than that, then really there were only seven miraculous days. Why are we celebrating for eight days?

Before you go cutting a branch off your menorah, let me tell you that there are many, many ways of answering this question.

For one, Rabbi Yosef Karo, author of the Shulchan Aruch (the authoritative code of Jewish law), provided two possibilities:

1. The Maccabees poured only one eighth of the oil into the cups of the Menorah for each night, and yet each night the oil burned an entire day. That makes one miracle per night.

The problem with this answer is: How did they know that only a small amount of oil would burn the entire night? And even if they somehow knew, the cups of the Menorah were supposed to be filled to the brim before each lighting. What made it permissible to fill the Menorah cups only partially in this case?

So Rabbi Yosef Karo provides another answer:

2. The Maccabees filled the cups of the Menorah each night, and the next day, they found the flask full again. Alternatively, they found the cups full again each morning.

The problem with this answer is—as Rabbi Infinity points out (and as Rabbi Chaim Soloveitchik pointed out long beforehand)—the oil in the Menorah must come from olives. Miracle Oil is not olive oil because it doesn't come from olives.

You might want to answer that it was a kind of burning bush miracle: There was a flame burning, but the oil was not consumed. But, no, that wouldn't work. The flame had to be produced by the combustion of olive oil, as the Torah says, "pure olive oil…as a luminary."

So the Rebbe, Rabbi Menachem M. Schneerson, points out another way of understanding the miracle: No new oil appeared from anywhere. Yet the amount of oil never diminished. And it was burning, non-stop. The oil was both burning and not burning at the same time.

Paradoxical? Yes. Or let's just call it a window on the Absolute Singularity from whom all of existence extends. A.k.a. G‑d.

For the whole story, dramatized and elucidated, see The Menorah Files.