|On the Unity of Isaiah|
This particular piece will be fairly short, because the issues here are relatively simple. One side, the traditional side, sees the Book of Isaiah as a basic unity composed by the prophet of that name at an early date - between 740-680 B.C. The other side says this book was put together by at least three authors, some parts early, some parts late.
And what are the arguments used to remove parts of Isaiah from the prophet by that name? There are basically two sets.
First, there are arguments related to internal structure. This includes alleged differences in style, vocabulary, and theological thought.
We need not say a lot about this set of arguments. Even critics who favor Isaianic disunity long ago acknowledged that arguments based on these premises are not decisive [McKn.2I, xv]. The more recent view, at any rate, has recognized that there is actually a great deal of continuity between the variously assigned sections of Isaiah, and is now, rather ironically, explaining this continuity in terms of a final redactor who smoothed things over and made Isaiah look more like a single-authored work, in some places using earlier material from the time of the original Isaiah (See for example OCon.CCLSI, Melv.NVI.) - thus offering an explanation for signs of early composition such as the antiquity of the Hebrew and the references to idolatry which would be anachronistic if the book were a later composition.
So, to the second argument set - using fulfilled prophecy.
Is. 44:28 "...who says of Cyrus, 'He is my shepherd and will accomplish all that I please; he will say of Jerusalem, "Let it be rebuilt," and of the temple, "Let its foundations be laid.' "
Is. 45:1 "This is what the LORD says to his anointed, to Cyrus, whose right hand I take hold of to subdue nations before him and to strip kings of their armor, to open doors before him so that gates will not be shut..."
We see these as a prophecy of the Persian king Cyrus - he who sent the Jews home from their Babylonian trials and authorized the rebuilding of Jerusalem and the temple. Pretty strong and specific stuff if authentic. What can the critics say?
It all boils down, of course, to a denial of predictive prophecy, and barring recovery of a manuscript dating earlier than Cyrus, all either side can do is stick by their presumptions.
Not that some haven't tried to go further; McKenzie, for example, argues [McKbn.2I, xv]:
That Isaiah...could use the name of a king, in a language unknown to him, who ruled in a kingdom which did not exist...taxes probability too far. It is not a question of placing limits to the vision of prophecy but the limits of intelligibility; even if the name were by hypothesis meaningful to the prophet, it could not be meaningful to his readers or listeners.
But if a revelation had come to me in 1975, "Koresh will cause trouble in Waco," the name would be meaningful neither to me nor to anyone I told about it. The context of the words, as in Isaiah, would tell us that "Koresh" was a proper name of some sort; we might not know the proper name of what specifically (a person? a dog? a battleship?), but it would be quite clear even 20-25 years before the fact that someone or something called "Koresh" was involved.
This would be so even if the prophecy were delivered in 1875; it might have been less clear in, say, 1675, before Waco existed also, but even then, the context would help us ascertain what the word intended.
Bottom line - what you think of Isaiah depends on where you start, and that's all that can be done until someone digs up a copy in the ruins that dates before the Exile.