What did Ferguson’s archaeological search establish?

Yes. Larson quotes him saying that in a 1976 letter. What evidence led him there?

You acknowledge his own conclusion and invite a discussion of the evidence behind it. The letter establishes his judgment.

His letter is private, so I would give the published field reports more weight.

Field reports can help assess the archaeological results. Start by answering the question about what Ferguson himself said, which the excerpt addresses directly.

We should wait until more sites are excavated before drawing conclusions from a missing crop.

More excavation can help. Even a partial search carries weight if it samples the right deposits and recovers comparable remains. Ask how well the existing search tested the prediction.

Yes, if a proposed site and period give us reason to expect the crop and the dig could recover it. Mosiah’s account of planting wheat and barley gives us a concrete claim to test.

You identify an actual material prediction and name what makes an absence informative. The proposed location, date, and preservation conditions all matter.

A revised map should have reasons of its own and make predictions we can check. I’d give a map less weight if it changes every time a test goes badly.

You apply the same standard to a new model. A proposed map gains weight when it makes specific predictions that a search could confirm or undermine.

Since the Church leaves specific locations open, I would move on to the spiritual message.

The spiritual message matters to you. Your friend is asking how a historical proposal can be evaluated. The Church’s position leaves the location open, so explain what would make a map worth testing.