From a Madhyamaka Buddhist perspective, if all things are unreal and illusory because they are open-empty (i.e. without an ultimately real foundation), then ostensibly “true” propositions are actually, in a sense, “false.” But because they are not entirely false (because otherwise this would assume the existence of a real truth posed in contrast to ostensible truths), their truths are truths in the way true statements about an event in a fiction are true: true only within the bounds of a constructed domain reflexively understood (or not) to be fiction.
This suggests that all of our various reference frames for gaining knowledge about reality produce constructed domains within which truths can be ascertained (validated as “objective” through an intersubjective correspondence between viewers who share the same reference frame) but are nonetheless only ostensible truths that are true within the fiction created and supported by the functioning reference frame. Key to note is that this account of global fictionalism completely preserves our practically functioning notion of truth, it just adds a metatheoretical understanding of the nature and function of truth.
Because there is no knowledge that does not make sense without a particular reference frame and correspondently enframed world that makes it intelligible, all knowledge is fictional, including the knowledge of this fictional nature itself. This does not undermine the claim to global fictionalism, since fictional truths are not entirely untrue — they are just partially or relatively true with regards to their reference frames. And since the notion of global fictionalism is a meta-theoretical notion about the nature of theōria itself, it is a reference frame that inclusively transcends all other reference frames and thus constructs the fictional domain in which it is assumed, for the purpose of elaborating the idea, that reference frames truly exist in any way. It is also a reference frame that is reflexively aware of its own nature as a reference frame, and thus also understands its own open-emptiness.
If all truths are only ostensible truths with fictional character rather than real truths with literal character, then this means that the world as we come to know it (and will always come to know), is imbued with and inseparable from value and meaning. Instead of being purely elements of an “internal” subjective viewpoint projected onto an “external” objective basis, value and meaning arise out of the creative mutual dependence or dependent co-arising of both subject and object (or “superject” i.e. subjects who function as objects for other subjects). Value and meaning are not the embroidery of a blank tapestry but are in fact the warp and weft through which the very fabric of the cosmos is woven.
This is why, fantastic imaginations of fractal buddha-bodies of incomprehensible scale incalculably populated by Buddhas and Bodhisattvas, infinitely abundant and extensive Pure Lands, empyrean heavens enjoyed by asuras and ghandarvas, and Boschian hells suffered by Narakalings, are metaphors for our own mind, which are nonetheless real places of rebirth and objects of experience. For global fictionalism, metaphors are embodiments of the text of matter, and signs are tangible significations of their own significance; in short: matter matters.