Is background information necessary?

Wayne Grudem said ("The Perspicuity of Scripture," Themelios 34 [2009]: 297):

I am reluctant to affirm that additional historical background information is ever necessary for getting a proper sense of a text.

Let's evaluate some reasons one might object to the necessity of background information to interpret the Bible. 

1) If background info is necessary, then that denies the perspicuity of Scripture. And once you deny the perspicuity of Scripture, that plays into the argument for the Roman Magisterium.

2) If background info is necessary, then we replace the priesthood of believers with the priesthood of scholars. The scholarly guild becomes our Magisterium.

3) Scholars like Peter Enns and John Walton cite background information to relativize the Biblical creation account (among other things).

Let's run through these objections:

Concerning (1),

i) The argument for the Magisterium is hypothetical. It stipulates that if certain consequences follow from the absence of a Magisterium, then that justifies the Magisterium. But the inference is fallacious. What if God permits those consequences? 

ii) The argument for the Magisterium is circular. Catholic apologists prooftext the Magisterium from the Bible. But if the Bible is not perspicuous, how do they know that their prooftexts apply to the Magisterium? Are they prooftexting the Magisterium with or without the Magisterium? If the former, then the prooftexts are superfluous–but if the latter, then the Magisterium is superfluous.

iii) If you read commentaries by modern Catholic Bible scholars, you will see that they employ the same methods as their Protestant counterparts. They, too, make use of background information. 

iv) The Magisterium doesn't have ancient history on Blu-ray. It doesn't have extra information on file. Indeed, the Magisterium isn't supposed to add to the deposit of faith. 

v) We can see from church history that the Vatican has no special insight or foresight. For instance, notice how the contemporary Magisterium disregards prior findings of the Pontifical Biblical Commission:

1. De narrationibus specietenus tantum historicis, Concerning only apparently historical narratives (June 23, 1905)

1. [ASS 38 (1905-06) 124]

1. [Italian, Latin]

1. De mosaica authentia Pentateuchi, On the authenticity of the Mosaic authorship of the Pentateuch (June 27, 1906)

1. [ASS 39 (1906) 377]

1. [Italian, Latin]

1. De quarto evangelio, On the authorship and historical truth of the fourth Gospel (May 29, 1907) 

1. [ASS 40 (1907) 383]

1. [Italian, Latin]

1. De libri Isaiae indole et auctore, On the nature and authorship of the book of Isaiah (June 28, 1908)

1. [ASS 41 (1908) 613]

1. [Italian, Latin]

1. De organo officiali Pontificiae Commissionis de re biblica, Regarding the official body of the Pontifical Biblical Commission  (February 15, 1909)

1. [AAS 1 (1909) 241]

1. [Italian, Latin]

1. De charactere historico trium priorum capitum Geneseos, Concerning the historical nature of the first three chapters of Genesis (June 30, 1909)

1. [AAS 1 (1909) 567-569]

1. [Italian, Latin]

1. De auctoribus et de tempore compositionis Psalmorum, Regarding the authorship and times of the composition of the Psalms (May 1st, 1910)

1. [AAS 2 (1910) 354]

1. [Italian, Latin]

1. De examinibus coram Pontificia Commissione Biblica subeundis, Regarding the evaluation of candidates for academic titles in Sacred Scripture (May 24, 1911)

1. [AAS 3 (1911) 47-50]

1. [Latin]

1. Quaestiones de evangelio secundum Matthaeum, On the Gospel according to Matthew (June 19, 1911)

1. [AAS 3 (1911) 294-296]

1. [Italian, Latin]

1. Quaestiones de evangeliis secundum Marcum et secundum Lucam, On the Gospels according to Mark and Luke (June 26, 1912)

1. [AAS 4 (1912) 463-465]

1. [Italian, Latin]

1. De quaestione synoptica, Concerning the synoptic question (June 26, 1912)

1. [AAS 4 (1912) 465]

1. [Italian, Latin]

1. Quaestiones de libro Actuum Apostolorum, Questions regarding the Acts of the Apostles (June 12, 1913)

1. [AAS 5 (1913) 291-292]

1. [Italian, Latin]

1. Quaestiones de epistolis pastoralibus Pauli apostoli, Questions regarding the pastoral Letters of the Apostle Paul (June 12, 1913)

1. [AAS 5 (1913) 292-293]

1. [Italian, Latin]

1. De epistola ad Hebraeos, On the Letter to the Hebrews (June 24, 1914)

1. [AAS 6 (1914) 417-418]

1. [Italian, Latin]

1. De parousia in epistolis Pauli Apostoli, The parousia in the Letters of Saint Paul (June 18, 1915)

1. [AAS 7 (1915) 357-358]

1. [Italian, Latin]

http://www.vatican.va/roman_curia/congregations/cfaith/pcb_doc_index.htm

To take a specific example:

http://www.stjeromebiblicalguild.org/pbc062706.pdf

Concerning (2), Biblical scholarship is not a secret society. Layman can examine the arguments of Bible scholars for themselves. This isn't just a case of taking their word for it. 

Concerning (3):

i) Scholars like Walton and Enns don't simply invoke background material to interpret the Bible. Rather, they claim that Bible writers are conceptually indebted to their sources. That this is where they got their ideas. And that denies the revelation and inspiration of Scripture. 

ii) Using background material to interpret the Bible assumes that you know how to interpret the background material. But as I've often argued, I think scholars like Walton and Enns misinterpret the background material. 

iii) Then there's the tricky issue of identifying background material. Is the material in question close enough in time and place to be relevant?  

http://www.reformation21.org/articles/background-in-biblical-interpretation-part-1.php

http://www.reformation21.org/articles/background-in-biblical-interpretation-part-2.php

iv) On a related note is the danger of parallelomania. Take Bruce Metzger's classic article:

http://www.frontline-apologetics.com/religions_christianity.html

I disagree with Grudem. But appeal to background info must be carefully qualified (see above).