UPDATE: David Byron has offered clarification in a comment, but I did not want to risk people missing it. Please see his response now included at the bottom of the body of the post.
One of the greatest worries with the Fristianity objection is that it is often defined in conflicting ways. For example Sean Choi writes, “Of course, Fristianity is not an actual worldview or religion, as is, for example, Islam. But no one – certainly not I – is claiming this.” Yet in a footnote Choi cites David Byron of the Van Til List as popularizing Fristianity. While contributing to the Van Til List Byron writes, “[T]he discussion of Fristianity already is a discussion of Islam, and indeed of any theistic faith that can with prima facie plausibility appeal to mystery to defend itself against internal negative critiques while boasting of its unique provision of transcendentals.” David Byron (Van Til List Archive July 2001 msg00012 http://www.ccir.ed.ac.uk/~jad/vantil-list/) While Choi denies that Fristianity is an actual worldview or religion such as Islam, Byron affirms that Fristianity is an actual worldview or religion such as Islam. While Choi states that “no one…is claiming” that Fristianity is an actual worldview or religion like Islam, the very source Choi gives credit to as having popularized the Fristianity objection claims that Fristianity “already is a discussion of Islam.”
Byron further adds that Fristianity is any theistic faith which can appeal to mystery. However, the objection that other theistic faiths are able to appeal to mystery just as the Christian theistic faith can in answering negative critiques is an altogether separate and unoriginal objection to the transcendental argument. The most charitable way to view the rather fundamental disagreement between Choi and Byron concerning Fristianity is to understand Byron as offering some tools of reasoning akin to those available within Christian theism which are allegedly available to actual theistic religions like Islam. The fear is apparently that Islam may develop a defensive apologetic which mirrors Christianity and may possibly even construct its own transcendental argument. This interpretation nevertheless does not fit well with what Choi has written concerning Fristianity.
Note also that Choi takes objection to Michael Butler’s comment as quoted by Choi, “If Fristianity is otherwise identical to Christianity, the only way for us to know [that its god is a quadrinity] would be for the Fristian god to reveal this to us.” Choi takes this proposition to be false and explains in note 32, “If Butler intends by this actual revelation, then, of course, his objection is confused.” He adds, “No God of a merely possible worldview can be the author of any actual revelation – any more than a merely possible angel can dance on a head of an actual pin.” Choi’s explanation precludes appeal to any actual Fristian revelation. Any appeal to actual revelation or theistic religion by the proponent of Fristianity is by Choi’s definition not consistent with Fristianity and constitutes a confused attempt at defense of the merely possible worldview.
(Geisler, Norman L. and Chad V. Meister, eds. Reasons for Faith: Making a Case for the Christian Faith. Wheaton, IL.: Crossway Books, 2007. 242-247)
UPDATE: David Byron has offered clarification in a comment, but I did not want to risk people missing it. Please see his response now included directly below.
You’d do well to expend more effort and charity on your sources; there’s little or no distance between myself and Choi in them on this point.
On the Van Til List from which you culled those quotes, I noted that Fristianity may be construed as a template. (More fruitfully, Fristianity may be construed as a Design Pattern in the GoF sense.)
Some strains of some actual religions satisfy that template. So do some hypothetical or projectable religions. Indeed, we can readily project (and even found, if we have the time and talent!) as many such religions as we wish.
Insofar as they satisfy that template, these actual, hypothetical, or projected sects exemplify Fristianity.
The tension you imagine above arises from neglect of this point: you consider (actual XOR abstraction) rather than (actual OR abstraction). Sometimes an actual thing is an instance, exemplar, or token of its type.
“Worldview” is a troubled concept all too often used as a crutch or facade. That aside, the upshot of the thought experiment is that a plurality of transcendentally equivalent “worldviews” poses a problem — perhaps insurmountable — for transcendental apologetics.
Hope that helps!