I was challenged to go after Rabbi Gottlieb's defense of the Kuzari argument, so I did. Read on...
This is Rabbi Gottlieb's version of the Kuzari argument. He gives two reasons why the gradual myth formation is not convincing. The first one is that the critics don't give any specific means by which the myth evolved and therefore there is no way to judge the plausibility.
But this is a poor argument. There are details in the traditional view that are literally miraculous and hence impossible to explain. Even an implausible myth generation is still more plausible than the impossible since it requires no magic to accomplish.
But even with that said, I think I can produce a very reasonable means by which the myth came to be. Moses was a real person who made a real speech in front of a real group of Israelites on a real mountain after he had helped them escape from slavery in Egypt. This is an entirely plausible event. I would say that he even ordered some laws from the mountain. I would even say that Moses spent some time alone on the mountain while he composed some text that he believed was spoken to him from God.
Is it so difficult to imagine this event becoming aggrandized over time? All the key players are already there. What's a few miracles and fireworks to work into the story over the course of centuries?
Rabbi Gottlieb provides his strawman scenario where all the ancient Israelites experienced was an earthquake, but there's no reason at all to be so minimalistic.
Rabbi Gottlieb's second reason is that there are no other examples of 'fictitious national unforgettables' meaning an event that would have been of vital importance to a nation but would not be true.
But this too is a strawman because 'myth' does not mean that the event is made up from nothing. As above, the Sinai story isn't strictly fiction, but a melding of truth and embellishment. And there are numerous examples of myths like that happening.
One excellent one is the great Kurukshetra War of ancient India. It was a great war, as recorded in the Hindu epic Mahabharata, that lasted only 18 days and brought the entire sub-continent to war. It involved almost every kingdom, save one, and had the combined total of almost four million soldiers counting both sides. An event of this magnitude would be impossible for the Indians to forget, but is it strictly true?
In the course of the war, fighters use numerous magical weapons, talk to various gods, and in the end there are only seven survivors. (But do note that I'm not depending on the battle survivors to validate the story, but for the rest of the Indian population which had to have known of this war and lived through the effects of depopulation.)
So was there an a Kurukshetra War? Probably. As Rabbi Gottlieb says, it's very difficult to make something like a national epic up and have people believe it. But are the details all correct? Did four million people really go to war? Were there really only seven survivors? Did they really use magic and talk to gods? I think those are just embellishments on a true story.