Revelation and Authority

In other words, one cannot simply assert that something is true because it is revelation. Anything that is taken as revelation must be justified, as one justifies any kind of claim.

I agree, but only because I find this as a consequence of Sola Scriptura. Before, It was tradition that justified the revelation of Scripture. Once tradition was taken out of the picture, people were left with three options: (1) to validate Scripture using itself, (2) to apply scientific methods of validation, and (3) to combine with compromise the previous options.

All these options are problematic, in my opinion. First, validating Scripture using itself is circular reasoning. Second, today's methods tend to be materialistic, so they are not suited for investigating supernatural claims. Third, the act of combining two errors leads to even more errors.

Without tradition, there is no assurance that Scripture is God's Word. For Catholics and Orthodox, they know that Scripture is revealed and authoritative because tradition--their authority--declares this.

In other words, without the "authoritarian", there could be no such thing as "authoritative".