In her new book, Ali Bonner's central claim is that Pelagianism was a category that was a “deliberately invented fiction” (302) conjured by Pelagius's opponents as a “distraction and smear” (26) to discredit him and his theological views. She offers five main arguments to support her claim. First, she says that Pelagius did not teach what his opponents accused him of teaching. She reviewed fourteen accusations against Pelagius listed in Augustine's De gestis Pelagii, which is the only extant source recounting the events at the Synod of Diospolis in 415 that declared that Pelagius was in harmony with the teachings of the Catholic Church, and she concluded that Pelagius taught only half of one of the accusations brought against him. Second, she compared Pelagius's writings to those from other Christian ascetic writers of the fourth and fifth centuries to demonstrate that his teachings were not fundamentally different from theirs. Third, she contends that there never had been a cohesive movement of individuals who asserted a shared Pelagian theological vision and that no one who had been accused of being a Pelagian ever taught what had been purported to be Pelagian theology. Her fourth argument is that scholars have failed to offer a coherent definition of Pelagianism and have failed to establish satisfactory criteria by which texts may be classified as Pelagian. Finally, she insists that the motive of Pelagius's opponents to condemn him was to:

These arguments rest on a flawed foundation. At the end of the introduction, the author asserts that the only extant texts from Pelagius that should be attributed to him are his Ad Demetriadem, Ad Celantiam, De uirginitate, and De diuina lege. She rejects his Expositio in Epistolas sancti Pauli because she (rightly) claims that it has been interpolated many times throughout the centuries. However, she says that “I also consider hearsay concerning Pelagius's teaching as reported by his opponents inadmissible as evidence. Quotations from otherwise lost works by Pelagius preserved in Augustine's writings may be admissible as long as it is borne in mind that they may be paraphrases and are necessarily seen out of context, without surrounding argumentation” (xviii). At no point does Bonner argue why the quotations from Pelagius should be considered “hearsay.” She simply makes the assertion as if it were obvious.

It is true that not all of the quotations from the Pelagians in Augustine's texts are necessarily reliable. Augustine admitted that the quotations in book 2 of his De nuptiis et concupiscentia had come from excerpts from Julian of Eclanum's Ad Turbantium that an unnamed person had copied. When Augustine later obtained a complete copy of Ad Turbantium, he recognized that the excerpts he had received earlier did not do justice to the text, prompting him to write his Contra Iulianum (epistle 207).

But, there is no reason to question the reliability of the quotations in Augustine's other anti-Pelagian texts. The quotations from Pelagius in book 3 of Augustine's De peccatorum meritis et remissione et de baptismo parvulorum come from a (yet to be interpolated) copy of Pelagius's Expositio in Epistolas sancti Pauli that Augustine most likely received from the Tribune Marcellinus, who almost certainly received it from Pelagius himself. Augustine's quotations of Pelagius in his De natura et gratia come from a copy of Pelagius's De natura that he had received from Timasius and James, who had been Pelagius's former students (De natura et gratia 1.1; Epistle 177.6, 179.2). The quotations from Caelestius in De perfectione iustitiae hominis come from a text he received from Eutropius and Paul, who received Caelestius's text from individuals from Sicily, where Caelestius had spent some time. Roland Teske has argued that it is possible that the entirety of Caelestius’s text is cited by Augustine. The quotations found in Augustine's De gestis Pelagii come from a copy of the minutes of the Synod of Diospolis that Augustine had obtained from Cyril of Alexandria (epistle 4*.2). The quotations in his De gratia and Christi et de peccato originali mainly come from Pelagius's Pro libero arbitrio, from the libellus he wrote for Pope Innocent (1.3.3), from Caelestius's statements at the Synod of Carthage of 411 that Augustine had read in the official minutes when he had visited Carthage (2.2.2), and Caelestius's libellus given to Pope Zosimus. The quotations from Julian in Augustine's Contra duas epistulas Pelagianorum come from letters that Pope Boniface gave to Alypius, who then gave them to Augustine. Finally, the quotations from Julian in Augustine's Contra Iulianum opus imperfectum, which offers the most quotations of any Pelagian author (approximately half of the almost seven hundred pages in the NCP translation are quotations from Julian), come from Julian's published Ad Florum, which Alypius obtained while in Rome and sent to Augustine. The provenance of the texts from the Pelagians that Augustine possessed, and the quotations themselves in Augustine's writings, do not offer any reasons why they should be rejected (with the noted exception of book II of De nuptiis et concupiscentia).

Bonner's conclusions are only tenable if the quotations from the Pelagians in Augustine's writings are ignored; if she were to give those quotations proper consideration, many of her arguments would fall apart, such as her claim that Pelagius never said that it is possible to be sinless (21), even though Augustine offered quotations from Pelagius's De natura and Pro libero arbitrio to prove the contrary (for example: De natura et gratia 7.8 and De gratia Christi et de peccato originali 1.4.5). If Bonner wants to convince her audience that the quotations from the Pelagians in Augustine's texts are “hearsay,” she must offer a convincing argument, not just an assertion.