According to that, an event like the Big Bang is also an event unfamiliar to us—so why should the principle of causality apply to it? This very rule shows that the Big Bang itself does not require a cause.

I want to be more precise: the intention is that whatever existed at the moment when the Big Bang occurred did not require a cause.

In that event, material objects familiar to us were created. It is a physical event. A physical event on the moon is also not familiar to us, and yet we still assume that it has a cause.

So the definition of the expression “objects within our experience” still isn’t clear to me. In what sense are the objects found on the moon within our experience?

They are of the kind that is within our experience. Even the objects in Australia are not within my personal experience.

In what sense is the matter on the moon / at the time of the Big Bang of the same kind? I have a feeling this is a definition that just isn’t sharp enough.

I have the impression that it’s sharp enough.

So in what sense is the matter on the moon / at the time of the Big Bang of the same kind?

In what sense are the chair next to me and the ceiling above me of the same kind?
This discussion isn’t going anywhere. I think we’ve exhausted it.

In the sense that humanity actually has experience with them. What happened at the time of the Big Bang does not fall under that definition. I’m really trying to understand—is this just an unsuccessful definition, or am I missing something? If so, I’d be glad to know what I’m missing.

What happened in the Big Bang was a quantum fluctuation, and there is nothing special about it.