Luther did Not Know What an Indulgence Was?

Here's one from an online discussion forum in which a defender of Rome argued: "Luther admitted later in his life that he actually didn't even know what an indulgence was" when the indulgence controversy erupted in 1517.  This assertion was shortly followed by this comment directed towards me: "Maybe our resident Genevan cyber defender can come in and white wash it for you guys." The straightforward argument appears to be that at the time of the indulgence controversy, Luther didn't know what an indulgence proper was: "He started his revolution on an abuse of something he later admitted he knew nothing about" (link). A source document to prove this claim from Luther was also provided (see below).

Documentation
First this link was given, and then a specific page and paragraph were cited from the same document (from a different source). Both of these links refer to Luther's 1541 treatise,  Wider Hans Worst. The first link appears to be from the first printing (there were four 1541 German printings, LW states the first was by Hans Lufft- see LW 41:183). The second link was to an 1880 printing. From the second link, the paragraph in question is the following:

This same text can be found in WA 51:539. This text has been translated into English: Against Hanswurst (LW 41:179-256). The quote is on pages 231-232. This treatise was written towards the end of Luther's life. In the section under scrutiny, Luther reflects back on the beginning of the indulgence controversy.

Context

It happened, in the year 1517, that a preaching monk called John Tetzel, a great ranter, made his appearance. He had previously been rescued in Innsbruck by Duke Frederick from a sack—for Maximilian had condemned him to be drowned in the Inn (presumably on account of his great virtue)—and Duke Frederick reminded him of it when he began to slander us Wittenbergers; he also freely admitted it himself. This same Tetzel now went around with indulgences, selling grace for money as dearly or as cheaply as he could, to the best of his ability. At that time I was a preacher here in the monastery, and a fledgling doctor fervent and enthusiastic for Holy Scripture.

Now when many people from Wittenberg went to Jütterbock and Zerbst for indulgences, and I (as truly as my Lord Christ redeemed me) did not know what the indulgences were, as in fact no one knew, I began to preach very gently that one could probably do something better and more reliable than acquiring indulgences.(86) I had also preached before in the same way against indulgences at the castle and had thus gained the disfavor of Duke Frederick because he was very fond of his religious foundation. Now I—to point out the true cause of the Lutheran rumpus—let everything take its course.

(86) See, for example, a sermon Luther preached on February 24, 1517. LW 51, 26–-31. See also two Lenten sermons he preached in March, 1518. LW 51, 35-–49.

[LW 41:231-232]

Elsewhere in the same document, Luther says something similar:

So my theses against Tetzel’s articles, which you can now see in print, were published. They went throughout the whole of Germany in a fortnight, for the whole world complained about indulgences, and particularly about Tetzel’s articles. And because all the bishops and doctors were silent and no one wanted to bell the cat (for the masters of heresy, the preaching order, had instilled fear into the whole world with the threat of fire, and Tetzel had bullied a number of priests who had grumbled against his impudent preaching), Luther became famous as a doctor, for at last someone had stood up to fight. I did not want the fame, because (as I have said) I did not myself know what the indulgences were, and the song might prove too high for my voice (LW 41:234; WA 51:541; Halle, 52).

Conclusion
LW 41 translates the sentence: "I (as truly as my Lord Christ redeemed me) did not know what the indulgences were..." Luther does not say: I did not know what an indulgence is. I would be surprised if Luther, a Doctor of Theology in the Roman church did not know what the basic concept of an indulgence was. For example, Pope Boniface in the 14th Century made use of a general indulgence in which certain times a year a general indulgence could be obtained. Another popular example is Pope Sixtus IV (only a short time before Luther) had his particular slant on indulgences applying to the living and the dead. It would be odd if Luther was not familiar with either of these papal approved indulgences. From his written record, Luther was certainly familiar with indulgences previous to the 1517 controversy  Heiko Oberman has stated,

Three years earlier, in the autumn of 1514, Luther had already denounced indulgences in the university lecture hall, terming them proof of the nadir Christendom had reached. There were Christians who thought money and a sigh would get them into heaven: "It is dangerous to believe that we can draw on the treasures of the Church without adding anything ourselves."(34)

(34): WA 3. 416, 27f.; 424, 22f.; gloss Ps. 68; approx. autumn 1514.

In regard to Oberman's documentation, here is WA 3:416. Here is WA 3:424. These pages are found translated into English in LW 10 (Luther's early lectures on the Psalms). Here is the English text corresponding to WA 3:416-

The third is now the prevalence of the lukewarm and the evil [peace and security]. For surfeit now reigns to such an extent that there is much worship of God everywhere, but it is only going through the motions, without love and spirit, and there are very few with any fervor. And all this happens because we think we are something and are doing enough. Consequently we try nothing, and we hold to no strong emotion, and we do much to ease the way to heaven, by means of indulgences, by means of easy doctrines, feeling that one sigh is enough (LW 10:351).

Here is some of the English text corresponding to WA 3:424,

Therefore woe to us, who are so snatched away by present things and foolishly do not see the devil’s trap! We act like the foolish heir who knew only how to squander the magnificent estate left by his parents and did nothing to build it up but always carried away from the pile. So the popes and priests pour out the graces and indulgences amassed by the blood of Christ and the martyrs and left to us, and they do not think there is any need to build up this treasure, nor to acquire the remission of sins and the kingdom of heaven in any other way than by their merits. Yet no one can share in the public good unless he, too, makes his contribution. To take from the church’s treasure and not also to put something back is impossible and deceitful presumption. [“He who does not work, should not eat either” (2 Thess. 3:10). He who is not a partaker of sufferings will not be a partaker of consolations either (2 Cor. 1:7)]. But they think they have this treasure ready in the safe so that they can use it whenever they want to. In their smugness they therefore surrender themselves to all the things that are in the world. Since the treasure obviously abides, while the world passes away, and since they want both, they first go after the world before it perishes, believing that heaven will be left over for them in abundance later. I say, this is what they think, that is, they act thus, that in fact they seem to believe it and to say what we read in Wisd. of Sol. 2:8, 5: “Let us crown ourselves with roses, before they are withered; for our time is the passing of a shadow.” But I am afraid that what has happened to prodigal heirs will also happen to us, namely, that, after all our goods have been dissipated and squandered, we become beggars and must endure every need in disgrace. Not that the church’s treasure can be used up, but I say that it can be used up as far as we are concerned. The treasure is unlimited in itself, but not for us, since a minority shares in it. Such a wastefulness of merits is present also in the religious, who scatter their brotherhoods and indulgences in every corner, just so they might have food and clothing. If they have these, they have no concern about such things. It is dreadful madness and wretched blindness that now we do not preach the Gospel unless we have to, not because we want to. And the number of such people is extremely large! O beggars, beggars, beggars! But perhaps the excuse is offered that you receive alms for God’s sake and that you reciprocate with the Word of God and all things without charge. So be it: You will see! (LW 10:361-362)

A much more practical way to read the sentence from Against Hanswurst  is that Luther was not aware of what the details were of the particular indulgences that were being hawked in Jütterbock and Zerbst. A similar conclusion is put forth by Michael A. Mullett in his biography of Luther,

The ambiguous form of words, 'I did not know what the indulgences were...' cannot, of course, mean, 'I did not know what indulgences were', and must therefore mean that Luther was in ignorance about this particular indulgence, itself a slightly implausible claim, given the extraordinary publicity surrounding and running ahead of Friar Tetzel. 

Mullet goes on to say that Luther's claim to not knowing the particular nature of Tetzel's indulgences is "implausible" on account of Tetzel's "extraordinary publicity." At least this author makes a rational historical criticism rather than the myopic contextless literalism employed by the discussion forum Roman Catholic.

Addendum

I did participate in  this discussion. From the time I stepped foot into it, it began to spiral out of bounds of the forum rules, provoking heavy deletions from the moderators, and in one case, a suspension of one of the Roman Catholic participants. There is a sense in which the recounting here of an interaction that occurred elsewhere is unfair.  If one wants to follow what remains of this discussion, the posts (that still remain, some edited by the moderators) from all interested parties occur in this order:

178; 181; 182; 185; 186; 188; 190; 191; 192; 193; 194; 195; 196; 197; 198; 199; 200; 201; 203; 204; 205; 208; 209; 212; 213; 214; 215; 216; 217; 218; 219; 220; 221; 222; 223; 224; 225; 228; 231; 233; 242; 260; 261.

The ultimate argument this defender of Rome appears to be making is that Luther's use of indulgences in the 95 Theses was "merely a convenient excuse to start his own revolt." His Luther is not an honest monk confronting the rampant abuses involved with indulgences. Rather, his Luther was already a deviant predisposed to revolt and simply needed a means to revolt. It does not necessarily follow that the indulgences mentioned in the 95 Theses were simply a means to revolt because Luther knew nothing or something about indulgences. He states, "Indulgences and their abuse were simply a convenient catalyst to begin his revolt. One need merely look at his what is glaringly absent in his Disputatio pro declaratione virtutis indulgentiarum, as many of what would become the core tenets of his own religious system were not yet crystallized." This use of "Disputatio pro declaratione virtutis indulgentiarum" also does not necessarily follow. Simply because something might be "glaringly absent" does not necessarily mean Luther was plotting to be a revolutionary and simply used indulgences as a means to revolt. I point this out to demonstrate on a presuppositional level, this defender of Rome's Luther appears to be his own concoction. He begins with a deviant man predisposed to revolt and then sifts Luther's writings to fill in what's needed.