Temporal Vastness and Architecture: A Comparative Analysis of Four Views of Time

The observable universe is unimaginably vast, stretching from the tiniest subatomic quark to clusters of galaxies billions of light years across. Yet as staggering as spatial vastness is, an even more mind-bending kind of vastness emerges when we consider different theories of time. Competing models of temporal reality propose wildly different ontologies – different answers to what exists in time – that make the physical scale of the cosmos seem almost modest by comparison. On one view, every moment of history and future already exists in a grand timeless ensemble; on another, every quantum possibility gives birth to an entirely new universe, multiplying realities beyond comprehension. By contrast, a stricter view insists that only the fleeting present is real, pruning reality to a razor-thin slice of now (at great philosophical cost). A newly proposed middle path tries to reconcile these extremes, granting reality to past and future while refusing to multiply worlds without necessity. In what follows, we compare four influential views of time’s ontology and the temporal vastness they imply: the Block Universe (Eternalism), which treats all times as equally existent in a static “block” of spacetime; the Many-Worlds Interpretation (MWI) of quantum mechanics, which explodes the Block Universe into countless branching timelines for every quantum outcome; Presentism, which asserts that only the present moment exists; and Existential Realism (ER), a recent framework that offers a disciplined middle ground by distinguishing what exists (strictly present entities) from what is real (a broader causal and informational structure including past and future). We will see that each view carries profound ontological implications – from a universe densely populated with dinosaurs and future aliens, to a multiverse of near-infinite extent, to a vanishingly small ontology of just the now. After outlining each theory, we conclude with reflections on the epistemic humility warranted by such extraordinary ontologies, and consider whether a moderate view like ER can capture time’s reality without the ontological excesses of its rivals.