Tenzin C. Trepp

Existential Realism (ER) is a recently proposed ontological framework that sharply distinguishes existence (actual, present being) from reality (a broader domain including non-present entities). ER was conceived to reconcile the intuitions of presentism (only the present exists) with eternalism (past and future are ontologically significant) in a two-tier view of time and being. This preprint surveys a range of open questions and forward-looking challenges that have emerged from the first generation of ER research. We chart key areas—metaphysics, physics, formal logic, phenomenology, cognitive science, and ethics—where ER’s framework invites further development. How does becoming (the passage from potential to actual) work in ER’s ontology? Can ER fully accommodate relativity and quantum physics without sacrificing its present-centric stance? What extensions to two-tier logic might capture phenomena like an open future or cross-temporal identity? How might ER engage with phenomenological accounts of time-consciousness or empirical findings about memory and anticipation in the brain? And what are the implications of ER for ethics, especially concerning our agency over time and responsibilities to future persons? Throughout, our tone is rigorous yet exploratory and humble: we outline problems and tensions rather than claim final answers. By mapping these open questions, we aim to stimulate interdisciplinary inquiry and guide the next stages of ER’s development.

Existential Realism (ER) is a novel ontological framework that distinguishes between existence (the empirically accessible present) and reality (the broader tapestry of past and future entities and events). This two-tier ontology preserves the primacy of the present now while granting ontological status to non-present times in a way that avoids the pitfalls of both presentism and eternalism. We summarize ER’s core definitions and motivations, drawing from metaphysics, cognitive science, and physics to illustrate why separating existence from reality matters. ER offers a synthesis: like presentism it holds that only the present exists, yet like eternalism it affirms that past and future entities can still be real. We provide examples from neuroscience (memory and anticipation), physics (causal traces and relativity), formal logic (truthmakers and temporal reasoning), and ethics (duties to past and future) to demonstrate ER’s explanatory power. We discuss implications for our understanding of time’s flow, the self’s persistence, causality, and moral agency. The tone is rigorous and realistic, yet forward-looking: ER is presented as both a capstone summary of an emerging framework and an invitation for interdisciplinary inquiry into the nature of time and reality.

Relativistic physics challenges our assumptions about time and existence. While eternalism posits a static block where all times equally exist, and presentism insists only the now exists, both struggle with relativity’s implications. Existential Realism (ER), recently introduced by T. C. Trepp, resolves this tension by distinguishing between “existence” (reserved for the present) and “reality” (which includes past and future insofar as they leave traces or can be anticipated). ER accommodates the relativity of simultaneity and the frame-dependence of “now,” avoiding the block’s metaphysical excess while preserving the ontological specialness of the present. This paper shows how ER reconciles relativity’s empirical content with a present-centered view that includes objective becoming and temporal continuity.

In both philosophy and science, standard logics struggle to model a key insight of Existential Realism (ER): that existence is a strictly present, empirical notion, whereas reality spans beyond the present. Classical first-order logic and even temporal modal logics tend to conflate being real with existing simpliciter, making it difficult to formally distinguish something that exists now from something that is real but not present. This paper introduces a formal two-tier logical framework tailored to ER’s ontology. We motivate this framework by showing how orthodox systems—from classical predicate logic to temporal modal logic—fail to capture ER’s core distinction between present existence and temporally extended reality. We then develop a layered logic with explicit operators or quantifiers for “existence-now” versus “reality-over-time,” including formal axioms that preserve ER’s asymmetries: only present entities exist (in the fullest sense), yet past and future entities can be real (ontologically significant) without existing. The logic adopts a modal-style treatment of time to model the collapse of potential into actual (present-becoming), and explicitly encodes causal asymmetry — where the past influences the present, but not the reverse. We illustrate the framework with symbolic representations, including an iconic “ER equation” capturing the relationship between reality and existence. To demonstrate its versatility, we apply the logic to examples from quantum physics (e.g. wavefunction collapse and delayed-choice experiments), cognitive neuroscience (memory traces and anticipatory processing), ethics (moral duties to future persons and the reality of future outcomes), and AI (agents modeling counterfactual or temporally extended scenarios). Finally, we show how the formalism sheds new light on classic metaphysical debates such as the truthmaker problem for past truths, persistence and identity over time, and the ontology of merely possible or future entities. Throughout, our presentation maintains a rigorous yet accessible tone, consistent with prior ER works, with technical clarity and footnoted references. The result is a self-contained preprint that extends T.C. Trepp’s Existential Realism into a formal logical system, demonstrating its broad applicability across science, philosophy, and practical reasoning.

Contemporary debates on the ontology of time often overlook their ethical ramifications. This paper introduces the ethical implications of Existential Realism (ER), a two-tier framework that distinguishes between what exists (the materially present) and what is real (including non-present but causally connected phenomena). We argue that standard presentism—holding that only the present exists—encourages a form of moral myopia, undervaluing future harms and past obligations. Conversely, eternalism’s block universe (where past, present, and future equally exist) risks a kind of moral fatalism, implying that future outcomes are fixed and beyond influence. In contrast, ER’s temporal ontology allows us to extend moral concern across time without positing that past or future entities exist in the same way present ones do. By affirming the reality of past and future (despite their lack of current existence), ER provides a coherent basis for caring about real-but-non-existent individuals and events. We develop an account of moral responsibility toward future persons and past injustices grounded in ER, and show how this approach illuminates real-world cases like climate ethics (responsibilities to future generations) and historical justice (acknowledging the reality of past harms). Briefly, we also consider implications for AI ethics and decision-making where long-term outcomes are at stake. Throughout, we demonstrate that a two-tier temporal ontology can integrate moral foresight and memory into a consistent framework, supporting intergenerational duties and a temporally expansive view of moral agency. We conclude by advocating a temporally grounded moral realism rooted in the ER framework, which reconciles the primacy of the present with the enduring moral significance of the past and future.

Existential Realism (ER) is an ontological framework that distinguishes existence from reality in the context of time. In brief, ER holds that only the present moment and its contents exist in the full ontological sense, yet much more than the present is real. Past events and future possibilities, though they do not exist now, are nonetheless real insofar as they leave traces, have causal effects, or figure in well-founded predictions. This two-tiered view is meant to reconcile epistemic humility about what we can directly observe (only the present) with a robust ontological realism about the world’s structure across time. In other words, ER asserts an objective world of matter, laws, and forces that unfolds in time, while acknowledging that our access to non-present times is indirect—mediated by memory, records, and inference. One potential gap in the current ER framework is the role of the human mind in structuring our experience of time. ER recognizes that we know the past through records and remember it, and anticipate the future through predictions, but it does not yet deeply explore how our brains and cognitive processes actively construct the subjective flow of time. Cognitive science and constructivist theories of mind suggest that time is not just “out there” in the world; it is also a mental representational construct that our minds assemble through processes like memory, narrative, anticipation, and temporal perception. Classic phenomenological philosophers such as Edmund Husserl and Henri Bergson, as well as modern cognitive scientists like Thomas Metzinger, have all emphasized that the stream of time we experience is shaped by consciousness. This report examines how integrating such insights from cognitive constructivism could enrich the ER framework. In particular, we will highlight cognitive science concepts – narrative memory, anticipatory processing, temporal binding, mental time travel, and the overall construction of subjective temporal experience – and evaluate whether ER currently underrepresents this subjective dimension of time. We then explore how ER’s temporal ontology could accommodate the fact that human access to past and future is structured by internal models, without compromising ER’s realist stance on an objective temporal reality. Finally, we address potential tensions between being epistemically humble (acknowledging the limits and constructions of our knowledge) and maintaining ontological realism, clarifying whether treating time as cognitively constructed undermines or, conversely, supports ER’s distinction between existence and reality.

Existential Realism (ER) is a present-centered ontological framework that distinguishes between existence, restricted to the present, and reality, which spans the causally or informationally relevant past and future. This paper explores how core processes of human temporal cognition—memory, anticipation, and the perception of the present—support ER’s framework. Insights from cognitive neuroscience suggest that the brain actively constructs time: the mind extends beyond the instantaneous now by retaining recent past information and projecting immediate future possibilities, all within a conscious “window of presence.” We examine how memory encodes past events both as physical traces in the brain and as reconstructed experiences in consciousness, how anticipation and predictive coding generate internal models of probable futures, and how our perception of ‘now’ is an integrated interval, not a dimensionless instant. These findings reinforce ER’s claim that only the present moment is ontologically existent, while past and future are real insofar as they are cognitively represented and integrated into the present through internal models. By linking philosophical ideas of time with empirical neuroscience, we show that human brains treat the past and future as parts of reality (through records and expectations) despite their lack of present existence. This interdisciplinary approach lends naturalistic support to Existential Realism’s view of time and offers a clearer understanding of why the present looms so large in experience even as past and future remain experientially—and ontologically—significant.

If only the present exists, how can we make sense of causal chains that stretch across time, the irreversible processes we observe in nature, and the one-way arrow of time? This question strikes at the heart of temporal metaphysics and physics. Existential Realism (ER) is a present-centered ontological framework that claims only present entities exist in the fullest sense, yet past and future entities are still in some sense real due to their causal connections and informational traces. Unlike standard presentism (which would render past and future wholly unreal, raising puzzles about truth, memory, and cause), ER draws a crucial distinction between existence and reality. Under ER, the present is the locus of existence, but the past remains ontologically real insofar as it has left enduring effects and information in the world. The future, likewise, though not yet existent, can be treated as real in the mode of anticipated possibilities that influence current plans and expectations. This nuanced ontology aims to resolve presentism’s classic problems — for example, how past causes can still have effects, or how past-tense statements can be true if the past is utterly nonexistent. In what follows, we will deepen the case for Existential Realism by showing how it accounts for causal relations, the linear order of time, the sense of temporal becoming, and the thermodynamic arrow of time. We will draw on insights from the philosophy of physics – including Hans Reichenbach’s analysis of time’s direction, Huw Price’s reflections on retrocausality and perspective, and Barry Loewer’s work on entropy and the “Past Hypothesis” – to demonstrate that a present-centric metaphysics can be fully time-compatible. Ultimately, we argue that ER not only accommodates modern physics but preserves our intuitive and scientific understanding of time’s asymmetries and the unfolding causal story of the universe.

Modern physics has increasingly highlighted the special role of the present moment in the unfolding of reality. Quantum experiments suggest that reality is not a static four-dimensional block but is actively determined in the present moment, as measurements seem to bring about definite outcomes only at the instant they are performed. This resonates with presentist intuitions (the view that only the present exists), yet strict presentism faces serious metaphysical problems. How can only the present be real, if past causes clearly leave effects and future events are anticipated? This paper advocates Existential Realism (ER) as a superior ontological framework that preserves the primacy of the present while accounting for the reality of past causes and future possibilities. Building on our earlier introduction of ER and critique of presentism’s limits, we will show that ER provides a richer ontology for quantum phenomena – one that distinguishes between existence and reality, and accommodates genuine becoming and temporal agency in ways that purely present-based theories cannot. We make bold but rigorous claims: that quantum mechanics “prefers” a present-centered ontology, and that Existential Realism best captures this without the pitfalls of naive presentism or the stagnancy of eternalism. In short, ER not only aligns with quantum physics – it elevates and refines the very notion of what it means for something to be real in time.

Quantum physics has dramatically reshaped our understanding of time and reality, revealing that the present moment occupies a uniquely privileged position within physical processes. In the first paper ("Quantum Physics Prefers the Present: A Temporal Ontology Grounded in Measurement"), we saw how quantum phenomena such as wavefunction collapse and measurement highlight the “now” as the only time when possibilities become actual. However, simply embracing presentism – the doctrine that only the present exists – is not enough. Presentism’s traditional metaphysical stance, which conflates existence with reality by declaring all non-present things unreal, runs into serious conceptual roadblocks when confronted with quantum experiments and the demands of causality and truth over time. This second paper advocates Existential Realism (ER) as a more nuanced and robust ontological framework that builds on those quantum insights while overcoming presentism’s limitations. By rigorously distinguishing existence from reality, ER provides a richer account of quantum phenomena – one that honors the special role of the present without erasing the past or negating the future. We will argue that ER better captures the ontology implied by quantum mechanics, from delayed-choice experiments and collapse theories to decoherence, and that it empowers a view of time where “becoming” and temporal agency are coherent and defensible. In short, Existential Realism preserves the empirical centrality of the present while acknowledging the tangible reality of past causes and future possibilities — making it a more comprehensive fit for quantum reality.

Modern quantum mechanics, despite its relativistic extensions, provides intriguing support for a present-centered view of time. This paper argues that quantum phenomena – indeterminacy, wavefunction collapse, the Born rule, and temporal asymmetries in measurement – challenge the static block universe of eternalism and instead elevate the present moment to ontological prominence. Remaining largely interpretation-neutral, we draw on a range of perspectives (from Einstein’s relativity to collapse models, and thinkers like Heisenberg, Rovelli, Maudlin and others) to show that quantum theory operationally distinguishes past, present, and future in a way classical physics did not. We examine how the measurement problem and the randomness of quantum outcomes resist a fully eternalist description, highlight how quantum mechanics introduces an arrow of time at a fundamental level, and consider proposals (e.g. GRW theory, delayed-choice experiments) that make a global present – or something akin to it – conceptually necessary. Classical philosophers and physicists from Einstein to Schrödinger are discussed alongside contemporary voices. While stopping short of endorsing any single ontology outright, we contend that the empirical success of quantum theory re-opens the case for presentism or related “A-theoretic” models of time. In closing, we introduce Existential Realism as a novel metaphysical framework aligning with these insights – one which preserves the special status of the present while accommodating the reality of past and future in a more dynamic ontology. The result is a rigorous yet accessible interdisciplinary inquiry: quantum physics, we conclude, prefers the present, suggesting time’s passage and the now are more than mere illusions.

Eternalism, or the block universe theory, maintains that past, present, and future events all exist equally in a four-dimensional spacetime. This paper presents a comprehensive critique of eternalism’s weaknesses across metaphysical, epistemological, phenomenological, and empirical dimensions. Metaphysically, eternalism’s commitment to all times being equally existent (in contrast to Existential Realism’s distinction between existence and reality) is argued to be an ontologically inflationary leap that raises problems of change and becoming. Epistemologically, we question how knowledge can extend to events that, under eternalism, “exist” beyond any possible observation. Phenomenologically, the block universe is at odds with the immediacy and flow of temporal experience, treating the vivid present as an illusion. Empirically, we challenge the common presupposition that the formalism of relativity theory straightforwardly entails eternalism – a philosophical extrapolation from physics rather than a necessary conclusion. Throughout, we engage with key voices: Einstein’s relativity-driven eternalism, van Fraassen’s empiricism, Markosian’s and Crisp’s defenses of a tensed reality, among others. We contrast eternalism with Existential Realism, a recent framework distinguishing existence (present, observable being) from reality (including past and future structures). This distinction preserves the empirical primacy of the present while affirming the causal reality of the past and the openness of the future. We argue that Existential Realism provides a more coherent and experientially anchored ontology of time. The critique is organized into numbered sections, each concluding with references. It is, in short, an anchored approach to time — one that preserves experiential reality without ontological excess.

Stoicism was one of the major Hellenistic philosophies, renowned not only for its ethical teachings but also for pioneering work in logic and epistemology. The Stoic school, particularly under Chrysippus of Soli (c. 279–206 BCE), developed a formal propositional logic that in some ways foreshadowed aspects of modern logical systems. This paper provides a rigorous comparative examination of Stoic reasoning and logic vis-à-vis modern logic traditions. We focus on the structure of Stoic logic (including its syllogistic forms and inference rules; the Stoics’ treatment of logical paradoxes such as the Sorites (the “heap” paradox) and the Liar, and the philosophical presuppositions underlying Stoic logic (notably its integration with ontology and determinism). In contrast, modern logic—particularly as developed by Frege, Russell, and the logical positivists of the 20th century—emphasizes formal abstraction and symbolic rigor. The analysis highlights how Stoic logic, though formulated over two millennia ago using ordinary language, anticipates certain ideas found in modern symbolic logic, while nevertheless differing significantly in purpose and context. In doing so, we shall see how key Stoic logicians like Chrysippus innovated logical theory, and how these innovations compare to the work of modern figures such as Gottlob Frege, Bertrand Russell, and the logical positivist school. Throughout the paper, a formal academic tone is maintained. Where appropriate, we include footnote references for further explication or sources, and a complete bibliography is provided at the end. It should be noted that our knowledge of Stoic logic comes from fragmentary sources and later reports, since no complete Stoic logical texts survive from antiquity. Nevertheless, scholarship has reconstructed a coherent picture of Stoic logical theory which we draw upon. The goal is to illuminate both the continuities and divergences between the Stoic logical tradition and the modern logical paradigms that dominate contemporary philosophical logic.

In both everyday language and philosophical discourse, the terms existence and reality are often used interchangeably. This conflation is especially evident in debates on the ontology of time. For example, an orthodox presentist will say that only present things truly exist, treating all non-present entities (past or future) as unreal in an absolute sense – “all such objects are unreal, according to Presentism,” as one defender neatly put it. This paper serves as a focused extension and clarification of the metaphysical framework introduced in Existential Realism – A Distinct Ontological Framework Beyond Presentism. It addresses specific questions raised by readers and critics: Is it coherent to distinguish existence from reality? What philosophical work does that distinction do? How does it help with longstanding problems like truthmaking, the status of unobservable entities, and future ethics? In short, while the original paper laid out the core ontological structure, this follow-up revisits its foundations to deepen the theoretical implications, refine key definitions, and explore practical consequences. Our central thesis remains: existence and reality are not identical. But here, we argue more sharply that separating them yields a more nuanced, empirically grounded, and philosophically productive ontology of time. We defend this view against objections, offer clarified examples, and explore its implications for epistemology, phenomenology, and ethics. We proceed as follows. Section 2 defines existence narrowly, in terms of presentness and empirical accessibility, drawing on the spirit of van Fraassen’s constructive empiricism. Section 3 then defines reality more broadly, to include causal and structural aspects of the world inferable beyond the present—illustrated through examples such as dinosaurs, future climate events, and cognitive anticipations. Section 4 explores how this distinction addresses several philosophical issues: the truthmaker problem for past truths, the ontological status of unobservable scientific entities, the phenomenology of temporal experience (in the sense of Husserl and Metzinger ), and considerations of metaphysical parsimony. Section 5 argues why this two-tier ontology is not merely a restatement of presentism or eternalism, but a distinct metaphysical framework. Finally, Section 6 summarizes our contributions and highlights new directions this view opens—particularly in ethics (e.g., our duties to future persons), AI models of time, and decision theory under uncertainty. Throughout, we maintain an academic tone and use end-of-paragraph references in line with the original paper’s style. Our aim is for this article to stand on its own as a focused argument on the existence–reality distinction, while continuing and enriching the foundation laid by Existential Realism.

This paper introduces Existential Realism as a novel ontological framework in metaphysics that offers a rigorously technical alternative to presentism. In contrast to standard presentism’s claim that only the present exists, In contrast to standard presentism, which claims that only the present exists, Existential Realism distinguishes between existence—material, empirically accessible presence—and reality, which includes causal, epistemic, and anticipatory structures beyond the immediate present. This framework integrates insights from metaphysics, epistemology, and phenomenology to address the limitations of presentism and related theories of time. We delineate how Existential Realism departs from presentism (and is not merely a variant thereof) by reinterpreting what it means for an entity or event to exist now, while still affirming the ontological significance of past and future entities as real despite their lack of present existence. Systematic comparisons are drawn between Existential Realism and the standard theories of temporal ontology – presentism, eternalism, and the growing block theory – with references to key contributors (Markosian, Crisp, Bourne, Zimmerman) to highlight differences in ontological commitments. We provide technically grounded examples—from causal traces in physics to cognitive-state evidence and time-indexed data structures—to show how entities can be real even without presently existing. The paper also addresses major objections, including the coherence of reality without existence, the epistemological access to entities that do not presently exist or are unobservable, and the compatibility of this framework with special relativity. A comparative table is included to map Existential Realism vis-à-vis other theories. In conclusion, Existential Realism is presented as a robust, integrative stance that preserves the empirical and experiential centrality of the present while acknowledging the enduring reality of the past and the looming reality of the future – thus serving as a stand-alone reference framework for future discourse in metaphysics and cognitive science.

This paper offers a rigorous examination of the concept of prosochē—the attentive mindfulness or vigilant focus on oneself—within Hellenistic Stoicism and its later transformations in Late Antiquity, and compares it to the modern psychological notion of the “flow state.” We analyze prosochē as a Stoic spiritual exercise (askēsis) essential to ethical development and life in accordance with cosmic reason (logos). Drawing on Pierre Hadot’s work and other scholarship, we detail how Stoic thinkers (especially Epictetus and Marcus Aurelius) conceived prosochē as continuous self-awareness and moral vigilance, and how this practice was adapted by Neoplatonist philosophers and early Christian ascetics. We then develop a comparative analysis between prosochē and Mihály Csíkszentmihályi’s concept of flow from contemporary psychology. Notable similarities include focused immersion, a harmonious affective state, and a sense of mastery or control during the experience. Key differences are also highlighted: prosochē is grounded in a teleological and moral framework oriented by cosmic nature and virtue, whereas flow is a content-neutral psychological state defined by optimal experience and lacking inherent ethical orientation. In sum, the paper situates prosochē as both an ancient practice of attentive presence and a precursor, with crucial differences, to modern ideas about absorbed states of consciousness. Footnotes provide references to primary sources (Epictetus, Marcus Aurelius, Plotinus) and modern analyses (Hadot, Csíkszentmihályi, cognitive science research), and the conclusion reflects on the enduring relevance of prosochē for philosophy and psychology.