Le passé existe-t-il encore ?

eternalism block universe theory special relativity Minkowski spacetime existence of past

Within modern physics and the philosophy of science, the dominant perspective on the nature of time is **eternalism**, commonly conceptualized as the **"block universe" theory**. Rooted in the principles of special relativity, this tradition holds that the past, present, and future are all equally real. Rather than time flowing continuously from a fixed past into an unwritten future, existence is an unchanging, four-dimensional structure. Under this view, past events do not cease to exist; rather, historical and future events are "already there" in the exact same sense that distant spatial locations are already there. The framework originated with Albert Einstein’s 1905 formulation of special relativity, but its profound ontological implications were crystallized by mathematician Hermann Minkowski. In his pivotal 1908 lecture "Space and Time," Minkowski mathematically fused the three dimensions of space with the single dimension of time into a 4D manifold, now known as **Minkowski spacetime**. He famously declared: "Henceforth, space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality". The primary mechanism mandating eternalism is the **relativity of simultaneity**. Because the speed of light is finite and absolute reference frames do not exist, observers moving at different relative speeds will disagree on whether two distant events happen at the same time. Because one observer’s objective "present" can simultaneously be another observer’s "past" or "future," there can be no universal, sweeping "now" across the cosmos. In the 1960s, philosophers Hilary Putnam and C.W. Rietdijk utilized this relativity to formally argue that physics fundamentally rules out *presentism* (the view that only the current moment exists). In this **static theory of time**, time is not an external metric by which the universe changes, but an *intrinsic* dimension of reality itself. While ongoing debates in quantum mechanics complicate the picture, the orthodox interpretation of relativity maintains that our subjective feeling of time "passing" is an evolutionary illusion, masking a block universe where the entire timeline unconditionally exists.

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Abhidharma concept of three times existence of past and future dharmas

Within Buddhist Abhidharma philosophy, a central ontological debate concerns whether *dharmas* (the fundamental constituents of reality) exist across the three times: past, present, and future. The orthodox **Sarvāstivāda** (literally, "All Exists") school affirmed this "tri-temporal existence". They posited that past, present, and future *dharmas* all exist as real entities (*dravya*), with each being "established in its intrinsic nature" (*svabhāva*). While a *dharma's* active causal functioning (*kāritra*) occurs only in the present moment, its intrinsic nature serves as "an atemporal determinant of real existence". Consequently, the Sarvāstivāda maintain that "all things exist" irrespective of their temporal status. The prominent philosopher Saṃghabhadra rigorously defended this ontological pluralism, arguing that a *dharma* can "enjoy three distinct but equally fundamental temporal modes of being". The Sarvāstivāda justified this model through the mechanics of karma and cognition. Because past actions yield present consequences, past karma must retain latent causal power. Furthermore, because Buddhist psychology holds that consciousness is intentional and must have a real object, the mere act of remembering the past dictates that past *dharmas* must still "exist from the intentional structure of cognition". Conversely, schools like the **Sautrāntika** and **Theravāda** (often categorized as Vibhajyavādins or "Distinctionists") rejected this model in favor of strict presentism. They argued the Sarvāstivāda view violated the core Buddhist principle of impermanence. The pivotal philosopher Vasubandhu argued that a *dharma* "only exists as a dravya for one moment" in the present. To explain how past karma influences the present without past *dharmas* literally existing, the Sautrāntikas introduced the concept of causal "seeds" (*bīja*)—traces or modifications planted in a subsequent mental continuum. This conceptual workaround later profoundly influenced Mahāyāna philosophy, serving as the precursor to the Yogācāra school's concept of "store consciousness" (*ālayavijñāna*).

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Zohar concept of time and the eternal present in the Sephirotic realm

In Jewish mysticism (Kabbalah), particularly within its foundational text, the *Zohar* (traditionally attributed to the second-century Rabbi Shimon bar Yochai and promulgated by the thirteenth-century mystic Moses de León), time is not strictly a linear progression. Instead, the Kabbalistic tradition views chronological time as a construct bound to the lower, physical world. In the higher Sephirotic realm—the ten divine emanations through which the infinite, timeless God (*Ein Sof*) reveals Himself—past, present, and future are unified in an "eternal present". This eternal present is vividly conceptualized in the Zohar's treatment of the upper Sephirot, particularly *Binah* (Understanding). In conventional Rabbinic Judaism, *Olam Ha-Ba* (the World to Come) often denotes a chronologically future messianic age or afterlife. However, the *Zohar* translates the Aramaic equivalent, *Alma de-Atei*, as "the world that is coming," shifting its meaning from a distant future endpoint to an ever-flowing, continuous present. This continuous stream is structurally associated with *Binah*, the "Divine Mother." As expressed in the *Idra Zuta* section of the Zohar: “That river flowing forth is called Alma de-Atei, the World that is Coming—coming constantly and never ceasing” (Zohar 3:290b). Within this realm, divine reality is experienced as a perpetual, boundless *now*. The chained descent of the Sephirot (the *Seder Hishtalshelut*) bridges the eternal and the temporal. While the lowest Sephirah, *Malkuth* (associated with the physical world of action, *Assiah*), represents the domain of sequential time and space, the higher emanations exist simultaneously outside of those boundaries. Kabbalah posits that linear time serves a vital purpose for the material world, allowing for moral development and narrative consequence; yet, the mystic’s ultimate goal is to pierce this veil. Through contemplation of the Sephirot, memory, and prophecy, the practitioner transcends linear chronology, accessing the timeless wisdom of the *Ein Sof* and directly experiencing the Divine as an eternal, unfolding present.

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Presentism vs Eternalism debate ontology of time and temporal parts

In analytic philosophy of mind and metaphysics, the ontology of time and the persistence of conscious subjects are fiercely debated through the lenses of Presentism and Eternalism. This discourse centers on whether the past and future are real, and how persons and objects maintain their identity over time. Eternalists argue that the past, present, and future are equally real, endorsing a "block universe" picture in which reality is a four-dimensional manifold. Within analytic philosophy, eternalism is closely coupled with *perdurantism* (or four-dimensionalism), a view championed by figures like David Lewis and Theodore Sider in works like Sider's *Four-Dimensionalism*. Perdurantists argue that objects persist by having distinct "temporal parts"—essentially extending through time just as they extend through space. To explain the continuity of a person's mind, Lewis pointed to the mental continuity and causal dependence between these successive temporal parts, conceptualizing persisting entities as metaphorical "spacetime worms". Conversely, *Presentism*, famously influenced by A.N. Prior, insists that only present objects and events exist; the past has "slipped out of reality" and the future is not yet actual. Presentism aligns naturally with *endurantism* (three-dimensionalism). Endurantists reject temporal parts, arguing instead that a persisting object is "wholly present" at every moment of its existence. As the Stanford Encyclopedia of Philosophy summarizes, if the past and future are not real, "there's nowhere and nowhen for any 'missing' parts to be". This ontological divide traces back to J.M.E. McTaggart’s 1908 distinction between the dynamic "A-series" (tensed time: past, present, future) and the static "B-series" (tenseless relations: earlier than, later than). Eternalists typically adopt the B-theory, arguing that our psychological experience of a flowing "now" is merely an indexical illusion. Presentists, adopting the A-theory, maintain that the flow of time and the privileged nature of the present are objective, fundamental features of reality that perfectly match our conscious experience of temporal passage.

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conservation of information principle Leonard Susskind holographic universe past events

In the realms of information theory and quantum physics, the **conservation of information** is a bedrock principle asserting that the fundamental information of any physical system cannot be destroyed. Because quantum mechanics and physical laws are deterministic, this conservation means that "you can always run a film backward". If one knows the complete quantum state of a system in the present, one can mathematically reconstruct all of its past events. As Stanford physicist Leonard Susskind states, "The equations of physics never allow information to disappear". This principle faced a severe theoretical crisis—known as the **Black Hole Information Paradox**—triggered by Stephen Hawking's realization that black holes emit thermal energy (Hawking radiation) and eventually evaporate. Hawking posited that any information concerning past events (such as the specific particles that fell in) is irretrievably lost when the black hole vanishes. Recognizing that this "would be undermined" if true, Susskind and Gerard 't Hooft engaged in a decades-long theoretical dispute with Hawking, often termed the "Black Hole War". To rescue the conservation of information, Susskind and 't Hooft pioneered the **holographic principle**. This concept proposes that our three-dimensional reality is essentially a "ghostly image of information recorded on a distant two-dimensional 'hologram'". In the context of a black hole, the information of past events is not destroyed at the singularity; rather, the data is "smeared out around the horizon". Susskind also introduced the distinctive concept of **black hole complementarity**. This resolves the paradox by positing that information can cross the event horizon from the perspective of an infalling observer, while simultaneously remaining encoded as highly scrambled data (or *qubits*) on the horizon's two-dimensional boundary from the perspective of an outside observer. Through this holographic lens, information theory dictates that the universe's past history is never erased, but fundamentally preserved on its dimensional boundaries.

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Ibn Arabi tajdid al-khalq perpetual creation and the status of the past

Stoic doctrine of eternal recurrence and the identity of indiscernibles in cosmic cycles

In Stoic cosmology, the universe undergoes infinite cycles of creation and destruction, governed by a perfectly rational divine *Logos*. Each cosmic cycle culminates in a universal conflagration (*ekpyrosis*) and is subsequently reborn or restored to its exact original state—a process known as *apokatastasis* or *palingenesis*. Because the universe unfolds according to strict causal determinism, every cycle repeats the events of the previous one identically. This doctrine of eternal recurrence creates a profound metaphysical tension with another core Stoic concept: the identity of indiscernibles. This principle dictates that if two entities possess all the exact same properties and cannot be distinguished, they must be numerically identical. The dilemma arises when examining individuals across different cosmic cycles. According to the theologian Origen in *Contra Celsum*, one variant of Stoic doctrine maintained that the Socrates of the next cycle "does not come to be again but an indistinguishable counterpart (*aparallaktos*) of Socrates, who will marry an indistinguishable counterpart of Xanthippe". However, if these counterparts are truly indistinguishable, the identity of indiscernibles dictates that they must be the exact same person. Ancient philosophers were highly aware of this paradox. Simplicius reports that the Stoics debated "whether the I [that exists] now and the I [that existed] then are one in number, or whether I am fragmented by the ordering of cosmic cycles one to the next". Alexander of Aphrodisias suggests that foundational figures like Chrysippus embraced strict numerical identity, writing that "after the conflagration all the same things come to be again in the world numerically". Because of this, modern scholars often debate whether the Stoics actually envisioned a linear timeline with exact repetitions or a single closed loop of circular time. To resolve the paradox of exact copies, later philosophers such as Plotinus suggested restricting the identity of indiscernibles strictly to a single cosmic cycle, though it remains unknown whether orthodox Stoics formally adopted this specific solution.

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• collegeofstoicphilosophers.org
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neural mechanisms of mental time travel episodic memory construction vs objective past

From the perspective of cognitive neuroscience, episodic memory is not a passive, video-like archive of the objective past, but a highly flexible, dynamic system. Rather than faithfully reproducing history, the brain actively pieces together stored elements (such as locations, objects, and people) to generate conscious representations of events. At the center of this paradigm is "mental time travel" (MTT), a concept pioneered by Endel Tulving. Tulving argued that human episodic recall relies on "autonoetic consciousness"—the subjective awareness of projecting oneself backward or forward in time. Building on Tulving's work, prominent cognitive neuroscientists Daniel Schacter and Donna Rose Addis introduced the *constructive episodic simulation hypothesis* in 2007. This influential theory posits that the neural machinery responsible for remembering the past is actually adapted to help us simulate the future. According to this hypothesis, "a key function of episodic memory is to support the construction of imagined future events by allowing the retrieval of information about past experiences and the flexible recombination of elements" into novel scenarios. Neuroimaging provides robust empirical support for this framework. fMRI studies reveal that remembering the past and imagining the future activate a shared "core network" in the brain, heavily recruiting the hippocampus, medial temporal lobes, prefrontal cortex, and posterior parietal cortex. Because both remembering and predicting rely on this shared mechanism of "episodic recombination," memory is intrinsically vulnerable to integration errors and distortions. In this neuroscientific tradition, a perfectly objective past is neurologically inaccessible. Instead, the brain stores fragmented memory traces, and recollection is always a "conscious act of construction, rather than a faithful re-enactment of the past". Ultimately, neuroscience suggests that memory's constructive unreliability is not a cognitive design flaw, but a crucial evolutionary feature that allows humans to flexibly plan for survival in an unpredictable future.

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