score:12
Plausible Quotations and Reverse Credibility in Online Vernacular Communities by Quentin Schultze and Randall Bytwerk (professors in the Department of Communication Arts and Sciences at Calvin College) traces the origin and spread of this misattributed quotation. Quoting:
The above quotation appears on a rapidly growing number of Internet pages. In 2002, it was on about a dozen pages; by mid-2008, it was 14,000. In mid-October 2009, the total was 47,900; on April 1, 2011, it reached 333,000. By December 1, 2011, the total surpassed 500,000. If one allows for partial quotations or minor variations, the figures are even higher. Forty thousand pages attribute it to "Joseph M. Goebbels." "M" was not his middle initial.
As best as we can determine, Goebbels never said it. Proving a negative is impossible, but we have read a wide range of Goebbels's writings and speeches without finding the quotation. (1) No one who cites it online or in available printed sources--including academic works--provides a source. The quotation also appears on over 400 Internet sites in German, sometimes with the note "retranslated from English," and sometimes with the wrong middle initial. (2) No German Internet page or book that we can find provides a source.
The authors provide more information at http://truthisthegreatestenemyofthestate.blogspot.co.uk/.