Critical realism seeks to chart a third way between the epistemologies of both modernism and postmodernism. It is critical because it accepts the postmodern emphasis on the provisional and always contingent or mediated aspect of knowledge, yet realist because it insists upon the objectivity of the world we encounter and so the possibility of more or less truthful ways of talking about the properties of this world ...
... Postfoundationalists agree with foundationalists that our worldviews can have greater or lesser correspondence with reality, including both scientific and theological truth. They agree with antifoundationalists (and nonfoundationalists), though, that the attempt to build a system of knowledge from a base of indubitable, infallible certitude that somehow stands on its own (whether this base is said to be the "plain" words of Scripture or human sensory experiences or something else) is an utterly failed epistemological project well past its sell-by date.
The postfoundationalist picture of knowledge has often been described as a "net" or "web" of truth, The strength and stability of a net does not depend upon any one of its nodes but upon the entire field as a unified whole. [Ronald E. Osborn, Death Before the Fall: Biblical Literalism and the Problem of Animal Suffering (Downers Grove, IL: IVP, 2014), 118-20]
A key point in debates concerning epistmology has been the sticking of foundationalism with modernist versions of foundationalisms, whether of the Cartesian project, the empirical project, or some fusion of the two. In these modernist epistemologies, the ground is to be some indubitable, transcendent timeless truths that form the foundation for building up the edifice of human knowledge. Needless to say, such foundationalisms even at the time of Descartes were not acceptable to the Christian faith. In this sense, Osborn is right to reject "foundationalism." The problem is whether such modernist foundationalism should be affixed to creationism at all. I would say not.
There are two main streams of creationism: the Fundamentalist and Evangelical stream, and the Reformed stream, and two interact with each other. Among Fundamentalists, the focus is on the reading of Scripture in a biblicistic manner, thus "God says it, it is true." There is always a tendency to read one's culture and assumptions into the text, yet to claim it as "foundationalist" in the modern sense is absurd, because the Fundamentalis are mostly not philosophers thinking about "indutible transcendent timeless truth." Their biblicism is a distortion of Sola Scriptura, yet because they are just treating the text naively, they function basically like premoderns in their epistemology rather than modernist foundationalists. Premoderns do not think about "indubitable transcendent truths," so while Fundamentalists are influenced by culture, it is one thing to claim influence by modernity, and another to claim a modernist epistemology. Osborn's accusation of Fundamentalists as "foundationalist" (in the modernist sense) is therefore in error.
Among the Reformed camp, many YECs embrace creation like premoderns too, as a look at the case for YEC in the 2004 OPC Creation Report, and also in the book The Genesis Debate, shows. These essays were primarily appeals to the traditional teaching of the church that believes in 6-24 creation, and thus Osborn's accusation of "foundationalist" also is in error. There is after all a difference between premodern naive realism and the much-maligned "common sense realism," because the latter consciously sticks to common sense readings and reasonings while the former does not.
I doubt there is therefore one epistemology for creationism. There are obviously many of the most vocal creationists who are empirical foundationalists. They are however others who are presuppositionalists, which is another version of Foundationalism. Presuppositionalism, both Vantilian and Clarkian, are different from the mainstream "modernist" foundationalisms. Vantilian foundationalism puts God as the foundation, while Clarkian foundationalism puts Scripture as the foundation. Both of them are "foundationalist" to the extent that the foundation are the basis for all of truth, and both of them are "critical" in the sense that they recognize the situatedness of all truth claims.
The problem with Osborn is that he does not recognize the difference between Reformed versions of foundationalism and the mainstream modern foundationalisms. Thus, he wrongly tars all creationists with the charge of modern Foundationalisms, while failing to recognize the alternate foundationalisms that some creationists hold to.