On naïve realism, the passage of cosmic time, and why special relativity dissolves one of philosophy’s most stubborn objections
An Analysis of Gesiel Borges da Silva “Spacetime and Perception: A Special Relativistic Defense of Naïve Realism”
Synthese (2026) 207:186 · DOI: 10.1007/s11229-026-05516-x
I · THE OPENING PROBLEM
The Star That Should Not Be Seen
On a clear night, you look up and see a star — a brilliant point of ancient light hanging in the black. You see it. It is, in every ordinary sense of the word, present to you: you experience its golden color, its steady luminosity, its particular place in the constellation of things. And yet, astrophysics tells you something quietly devastating about this encounter: that star died a million years ago. What you are seeing is not a star but an obituary written in light, a message dispatched from a supernova before humans existed, only now completing its journey to your retina.
This is not merely a poetic curiosity. It is, for a certain school of philosophy of perception, a genuine crisis. The school in question is naïve realism — also called direct realism or relational realism — and the crisis goes by the name of the time-lag objection. Understanding why this objection bites, and why a recent paper in the journal Synthese argues that Einstein’s special theory of relativity dissolves it entirely, requires us to walk carefully through some of the deepest questions in the philosophy of mind and the physics of spacetime.
What follows is a sustained examination of both the philosophical problem and the proposed solution — one that draws not on metaphysical speculation but on well-confirmed physics. Along the way we will encounter the nature of perception, the geometry of spacetime, the meaning of “now,” and the strange ways in which light connects us to the universe’s past without severing us from reality’s present.
II · THE PHILOSOPHY
What Naïve Realism Actually Claims
Naïve realism is a view about the fundamental nature of conscious perceptual experience. Its central claim sounds almost tautological: when you see a red ball, your visual experience is constituted — literally, essentially made up — by the red ball itself and its properties. The redness, the roundness, the shininess are not representations in your head, not neural codes, not mental images. They are the ball’s actual properties, directly present to consciousness.
This stands in sharp contrast to the dominant rival view in philosophy of mind: representationalism. Representationalism holds that all perception is mediated by internal mental representations. You never actually see the world directly; you see a model of the world constructed by your brain from sensory data. The external object causes a representation in your mind, and it is that representation — not the object — which constitutes your experience. Naïve realism rejects this with unusual force: it says the representationalist picture involves one intermediary too many. Genuine perception just is the direct sensory presence of the world to a subject.
CORE CONCEPT
The Constitution Thesis
Naïve realism’s central claim is that perceptual experience is not merely caused by external objects but literally constituted by them. The object and its manifest properties are essential, non-detachable parts of the perceptual episode itself. Remove the object, and you no longer have the same experience — you have, at best, a hallucination that resembles one.
This is why naïve realism draws such a sharp line between veridical perception (genuine seeing of the world) and hallucination or illusion. A hallucination of a red ball is not constituted by a red ball — there is no ball involved — and so it is, for the naïve realist, a fundamentally different kind of mental event, even if it feels subjectively similar. The naïve realist is committed to a form of what philosophers call disjunctivism: the good and bad cases of experience are not species of a common genus but are, at the deepest level, distinct phenomena.
This is a brave and intuitively compelling picture of perception. It respects common sense. It avoids the Cartesian trap of locking consciousness behind a wall of representations. It preserves what feels most undeniable about perceptual experience: the direct presence of the world. But it comes at a cost — a vulnerability that critics have long exploited.
III · THE PROBLEM
The Time-Lag Objection, Laid Bare
The trouble begins with the most ordinary of physical facts: light takes time to travel. When you look at a candle across the room, you see it not as it is now but as it was a few nanoseconds ago. When you look at the Moon, you see it as it was 1.3 seconds in the past. When you look at the Sun, you see it as it was eight minutes ago. And when you look at that beautiful star — well, you see it as it was however many light-years away it sits. For nearby stars, this is decades or centuries. For distant ones, millions or billions of years.
For naïve realism, this creates a serious structural problem. The view holds that a genuine perceptual experience is constituted by its object — the object must be genuinely present, essentially involved, non-replaceable. But for objects to genuinely constitute anything, they must, presumably, exist. A nonexistent object cannot be a constituent of anything. And the star is gone.
P1
If naïve realism is true, then a perceptual experience is constituted by the external object and its manifest properties.
P2
If a perceptual experience is constituted by the external object, then the experience and its constituting object must exist simultaneously.
P3
In some cases (e.g., the perception of distant stars that have since exploded), the experience and the object do not exist simultaneously.
∴
Naïve realism is false.
The premises each carry genuine philosophical weight. Premise 1 is simply the core claim of naïve realism. Premise 2 rests on what seems like a bedrock intuition about constitution: if A constitutes B, A must exist when B exists. Premise 3 is then just an empirical observation backed by astrophysics: we absolutely do see things that no longer exist. The philosopher C.D. Broad gave canonical voice to this intuition in 1925: it is, he insisted, “of the essence of a perceptual situation that it claims to reveal an object as it is at the time when the situation is going on.” The argument seems watertight. Naïve realism appears to be committed to something physically impossible.
IV · PRIOR ATTEMPTS
How Naïve Realists Have Previously Responded
The objection is old enough that several responses exist in the literature. Two deserve serious attention before we arrive at the special-relativistic approach that is the paper’s main contribution.
The Eternalist Gambit
The philosopher Aidan Moran has suggested that the naïve realist embrace eternalism — the metaphysical view that all times are equally real, that the past and future exist just as robustly as the present. On this four-dimensionalist picture of time, the star is not truly “gone.” It is located in a region of spacetime that happens to be earlier than now, but earlier does not mean nonexistent.
Aidan Moran
ETERNALIST STRATEGY
Proposes naïve realists embrace four-dimensionalism: past objects exist at their own times just as spatial objects exist at their own places. The dead star “exists” in its past location in spacetime and can therefore genuinely constitute present experience.
Zhuofan Gu
NON-TEMPORAL CONSTITUTION
Argues perception is a non-temporal constitutive relation — more like fatherhood than brick-and-mortar composition. The constituent need not coexist with the constituted. A father constitutes a son’s identity without being present whenever the son exists.
Moran’s response is ingenious, but it purchases the defense at too high a price. Eternalism is itself a highly contested philosophical view. Many philosophers are presentists (only the present exists) or growing-block theorists (the past and present exist but not the future). By tethering naïve realism to eternalism, Moran makes its truth depend on winning a completely separate and very difficult debate about the metaphysics of time.
The Non-Temporal Constitution Strategy
Gu’s approach is more creative. He proposes that the constitutive relation in perception is non-temporal — meaning the constituent and constituted need not coexist. Just as a father constitutes a son’s identity in some important sense without the father needing to be present whenever the son exists, the dead star might constitute Abraham’s experience without being contemporaneous with it.
This has appeal but carries its own problem. There is, as da Silva argues, a disanalogy between fatherhood and perception that matters deeply. Non-temporal constitutive relations typically involve things that existed at some point and left a causal imprint that carries forward. But naïve realism’s entire raison d’être is that the object is directly present to consciousness — not merely causally efficacious from a distance. By making constitution non-temporal, Gu saves the letter of naïve realism while abandoning its spirit.
THE DEEPER PROBLEM
Both prior responses — eternalism and non-temporal constitution — share a crucial defect: they require naïve realism to accept substantial additional philosophical commitments. They make the truth of one theory of perception depend on winning independent battles in the metaphysics of time or the theory of constitution. A better defense would fight the time-lag objection on its own terrain without these extra burdens. This is precisely what special relativity makes possible.
V · THE PHYSICS
Einstein’s Gift: Simultaneity Reconsidered
To understand da Silva’s solution, we need to take special relativity seriously as a theory of what time actually is — not as an exotic physicist’s tool, but as our best-confirmed description of the structure of physical reality. And special relativity says something that ought to be more philosophically disturbing than it usually is: there is no such thing as absolute simultaneity.
In Newton’s classical physics, time flows uniformly and universally. “Now” is the same for everyone, everywhere. Two events are either simultaneous or they are not — that’s a fact independent of who asks the question. Special relativity destroys this picture completely. Whether two spatially separated events happen “at the same time” is not an absolute fact about the universe. It is a fact relative to a particular inertial reference frame — a particular state of motion. Two events that are simultaneous for an observer at rest on Earth can be non-simultaneous for an observer moving past at high velocity, and vice versa.
This is not a measurement error or a limitation of our instruments. It is a fundamental feature of spacetime. The reason is well understood: simultaneity is defined by the synchronization of clocks, and clock synchronization depends on light signals, and light signals travel at a finite speed that is the same in all reference frames. These facts together make simultaneity irreducibly relative.
What is not relative, crucially, is the causal structure of spacetime. Whether two events are causally connected — whether one lies in the “light cone” of the other — is an absolute, frame-independent fact. If light from the star’s explosion can reach Abraham’s eyes, then E₁ (the emission) is in the absolute past of E₂ (the perception) in every possible reference frame. No boost, no change of perspective can undo this. The causal ordering of lightlike and timelike separated events is invariant.
The Light Cone as the Geometry of Perception
Da Silva’s central move is to translate naïve realism’s constitution claim into the language of spacetime geometry. Instead of asking whether the star and Abraham’s experience exist “at the same time” — a question that special relativity reveals to be under-specified — we ask whether the star’s emission event lies on Abraham’s past light cone. This is the right question. And its answer is frame-independent.
When Abraham sees the ancient star, two events are connected: E₁, the emission of light from the star, and E₂, the arrival of that light at Abraham’s eyes and the corresponding perceptual episode. These events are connected by a lightlike geodesic — a path through spacetime traced by a photon moving at speed c. The spacetime interval between them is zero: Δs² = c²Δt² − Δx² = 0. This is an invariant. Every observer in every reference frame agrees on it.
The naïve realist can now reformulate the constitution claim: the star’s manifest properties constitute Abraham’s perceptual episode when and because the star’s world-line intersects Abraham’s past light cone. This is not a claim about simultaneity. It is a claim about causal and geometrical connection in spacetime. And it is precisely as well-founded for distant stars as it is for the nearby red ball on the table.
VI · THE SOLUTION
How Relativity Dissolves the Objection
With the relativistic machinery in place, the time-lag objection can be met not by denying any of its premises but by revealing that its premises cannot be jointly true within any single inertial reference frame. This is the heart of da Silva’s argument, and it is elegant in a way that the eternalist and non-temporal constitution strategies simply are not.
Return to the argument’s structure. Premise 2 says the experience and the object must exist simultaneously. Premise 3 says they do not. The objection claims both are true — together, simultaneously, in the same epistemic situation. But the moment we ask “simultaneous in which frame?” the joint truth of the premises becomes impossible to establish.
Frame by Frame
Consider Abraham’s own rest frame S. In this frame, the constitution relation holds — the starlight arrives, Abraham’s experience occurs, the light cone connection is established. Premise 2 as stated — that the constituting object must simultaneously exist — is simply false in this frame. The star exploded millions of years ago in S’s time coordinates. But this does not defeat naïve realism; it just means Premise 2 is not a requirement that falls out of naïve realism when properly understood in relativistic terms. Constitution does not require temporal simultaneity; it requires lightlike connection.
Now consider the star’s own rest frame S′. In this frame, the star ceased to exist long before Abraham’s observation. Premise 3 (object and experience non-simultaneous) is true. But the constitutive connection still holds in this frame too, because the light cone connection is frame-invariant. The objector would need Premise 2 to be true in this frame as well — but it isn’t. The naïve realist’s constitution claim (properly recast as a light cone claim) does not require simultaneity in S′ either.
“A pair of events can be causally connectable or strictly simultaneous in some inertial frame, but never both at once. The time-lag objection requires both — and the geometry of spacetime forbids exactly that combination.”
— Da Silva’s central insight, paraphrased
What about a “third frame” S″ chosen specifically to make the emission and perception events simultaneous? Here the geometry is decisive. For two lightlike-connected events — events connected by a signal traveling at c — no Lorentz boost can make them simultaneous. A finite boost always leaves a nonzero time difference Δt′ ≠ 0. If you somehow forced simultaneity by choosing a spacelike connection, you would break the causal connection — E₂ would fall outside E₁’s light cone, which means the light from the star could not have caused Abraham’s experience. You would be describing a perceptual episode that the star couldn’t have produced.
The objector is thus caught in a trap of spacetime geometry. To have Premises 2 and 3 jointly true — in a single frame, at a single moment — requires a configuration that physics forbids. No inertial frame satisfies both requirements simultaneously. The argument is not merely weakened; it is structurally undermined.
VII · WIDER SIGNIFICANCE
What This Means for the Philosophy of Perception
The Methodological Lesson
Da Silva’s approach exemplifies what we might call physicalized metaphysics: the practice of resolving apparently intractable philosophical disputes by attending carefully to what our best confirmed physical theories actually say about the structure of reality. The time-lag objection was framed in pre-relativistic terms — absolute time, universal simultaneity, a single objective “now.” These are concepts that special relativity has definitively superseded. A philosophical argument built on pre-relativistic intuitions about time is not just wrong; it is anachronistic.
This is a genuinely important methodological point. Philosophy of perception has sometimes proceeded in isolation from physics, treating the nature of perception as if it could be fully resolved by conceptual analysis alone. But perception is a physical process. Photons travel through space. Retinas transduce electromagnetic energy. Neural signals propagate at finite speeds. All of this happens in spacetime, and spacetime has a structure revealed by relativity. Philosophical accounts of perception that ignore this structure are not merely incomplete — they risk being positively wrong.
What Perception Actually Is, in Spacetime
There is something philosophically rich in the recast picture of perception that da Silva’s account implies. On this view, a perceptual episode is a node in the causal-geometric structure of spacetime. It is the arrival point of a lightlike (or subluminal) geodesic that traces back to the object’s world-line. The “direct presence” that naïve realism talks about is not presence in the sense of temporal simultaneity — it is presence in the sense of spacetime connection.
THE RECAST PICTURE
Perception as Spacetime Constitution
An object O constitutes a perceptual episode P when the world-line that carries O’s manifest properties intersects P’s past light cone. This is an invariant, frame-independent condition. It does not require temporal simultaneity. It requires causal-geometric connection — and this holds as robustly for distant stars as for nearby objects.
The Parsimony Advantage
One of the most powerful features of this approach is its parsimony. It requires no new metaphysical commitments. It does not need eternalism or presentism or growing-block theories of time. It does not need non-temporal constitution or any other exotic philosophical machinery. It requires only special relativity — a theory we already accept on independent grounds, confirmed to extraordinary precision by a century of experiments.
The contrast with Moran’s eternalist strategy is particularly sharp. Both approaches deny Premise 2 — both say the naïve realist is not committed to temporal simultaneity between perceiver and object. But Moran denies it by adding a disputed metaphysical theory; da Silva denies it by pointing to accepted physics. The latter is simpler, better grounded, and more convincing.
VIII · CRITICAL EXAMINATION
Where the Argument Might Be Pressed Further
No philosophical argument is beyond scrutiny, and da Silva’s approach — elegant as it is — raises questions worth pressing. Not as objections that defeat the view, but as avenues for further development.
The Scope of the Solution
The argument works most cleanly for perception of objects connected to the perceiver by lightlike signals — photons traveling at c. But most ordinary perception involves light passing through media — glass, water, atmosphere — where the group velocity is less than c. In these cases, the path from emission to perception is timelike rather than lightlike. Da Silva acknowledges this and notes that the argument still holds: sub-luminal paths keep every intermediate event inside the future light cone of E₁. The constitution connection is preserved.
The Nature of Properties Carried Through Spacetime
There is a philosophical question lurking in the description of light as “carrying” the star’s properties. In what sense does a photon carry redness? Photons have frequency and energy; redness is a quality that depends on how a nervous system processes certain frequencies of electromagnetic radiation. Is it coherent to say the photon “carries” the star’s manifest property of yellowness when yellowness, strictly speaking, is a relational property that requires both a stimulus and a perceiver?
The naïve realist can reasonably say that the star possesses objective physical properties (spectral emission patterns) and that these are literally transmitted through spacetime, and that what the perceiver experiences as yellowness is the direct encounter with those objective properties. Whether that preserves everything the naïve realist wants to say about “manifest properties” depends on further commitments in the theory of color and secondary qualities.
Does the Argument Establish Too Much?
One might wonder whether the special-relativistic argument, if successful, implies that naïve realism can accommodate any perception, no matter how indirect or delayed. After all, any light-based perception involves a light cone connection. But the light cone connection is not sufficient on its own for naïve realist constitution — it is necessary. The naïve realist still needs to say what it is about the specific causal-geometric connection between object and perceiver that makes it a case of direct perception rather than mere indirect causal influence.
IX · CONCLUSION
The Light That Never Really Left
There is something quietly profound in the picture that emerges from da Silva’s analysis. Naïve realism, properly understood through the lens of special relativity, does not describe perception as a transaction occurring at an instant in time. It describes perception as a relationship across spacetime — a causal-geometric bond between an object and a perceiver, stretched along a null geodesic, invariant across all reference frames.
There is something almost consoling in this. When you look up at that ancient star and receive its light in your eye, you are not being deceived. You are not apprehending something that has nothing to do with the star. You are receiving — directly, causally, invariantly — the physical signature of an object that was once genuinely there. The universe has kept faith with you across the light-years. What constitutes your experience is the star’s own properties, traveling at the speed of light, arriving at the exact moment and in the exact form that makes your perceptual episode possible.
“Something in your eyes took a thousand years to get here.”
— U2, “Iris (Hold Me Close)” — Epigraph to the paper
The song lyric with which da Silva opens his paper turns out to be more than a poetic flourish. It is a precise description of what is philosophically at stake. The light in your eyes — the light that constitutes your experience — did take a thousand (or a million) years to get here. But it got here. It maintained its causal continuity across the void. And in arriving, it brought with it the genuine presence of its source.
Special relativity does not make perception seem more mysterious; it makes it seem, in a strange way, more intimate. The universe’s past is not gone from us. It is threaded through the present in every beam of ancient starlight, reaching across spacetime to touch our retinas and — if the naïve realist is right about the nature of experience — to constitute the luminous fact of our perceptual encounter with the world.
The time-lag objection assumed that time is absolute, that “now” is universal, that the star’s non-existence-now must disqualify it from constituting experience-now. Special relativity shows that none of these assumptions is true. Once they are abandoned — once we take seriously what physics actually says about the structure of time — the objection dissolves, and naïve realism stands.
Reference
Da Silva, G. B. (2026). Spacetime and perception: a special relativistic defense of naïve realism. Synthese, 207, 186. https://doi.org/10.1007/s11229-026-05516-x
