12.3 Refuting Observations and Preferred-Frame Tests
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Two kinds of observation would count directly against the ontology: a confirmed physically realized
closed timelike curve, and a retrocausal dependence in the interventionist sense, P(O_t |
do(F_{t+Δ})) ≠ P(O_t) that cannot be reduced to correlations, post-selection, or boundary
conditions, and cannot be eliminated by an empirically equivalent formulation without
retrocausation. Time-symmetric descriptions and correlations with later variables do not meet this
standard. Either would contradict the requirement that each present be generated from its past alone
(§9.4.2; §13). No maintained physical connection between the present and a past or future moment has
ever been observed; phenomena that suggest one — entanglement between photons that never coexisted,
delayed-choice erasure, violations of temporal Leggett–Garg inequalities — establish correlations
among present records, not persisting links across time.
Other observations would change the cost of holding the ontology without deciding it. A physically
preferred global foliation, whether detected as preferred-frame effects or required by an
empirically successful theory of quantum gravity, would remove the principal relativistic objection
to presentism, though an eternalist may accept such a foliation too. Conversely, Lorentz invariance
confirmed to ever deeper levels raises the cost without refuting the view.
CTGP inherits the local phenomenology of general relativity: the cosmological frame has no effect on
local physics. Because the generative present is defined by cosmological time and introduces no new
field, the preferred-frame parameters that would couple local physics to the CMB rest frame vanish.
For an observer moving through that frame at v/c ≈ 1.2 × 10⁻³, such couplings of strength α would
produce sidereal and annual modulations of clock rates and propagation of order α(v/c)². Lunar laser
ranging and pulsar timing bound the relevant post-Newtonian preferred-frame parameters at about 4 ×
10⁻⁵ and 2 × 10⁻⁹ (Will 2014), and atomic-clock and spectroscopic comparisons bound preferred-frame
effects on matter far more tightly (Kostelecký and Russell 2011). All such results are null, as CTGP
requires. They are consistent with CTGP but do not discriminate it from eternalism, which makes the
same prediction. Preferred-frame theories with a dynamical timelike vector, such as Einstein–æther
and khronometric gravity (Jacobson and Mattingly 2001; Hořava 2009), are the natural comparison
class, and their bounds apply to any Layer 3 extension of CTGP that would give the generation flow
independent dynamics. The two halves of this claim should be stated together. CTGP introduces no
local Lorentz violation and no new local field; it does commit to a globally distinguished foliation
wherever cosmological time is regular. The null results above bear on the first half, not the
second, and no measurement of local physics could bear on the second.
12.4 Operational Locatability of the Present
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The generative present is not a posit beyond the reach of measurement. The universe contains nearly
universal reference structures through which it becomes measurable: the CMB, the most comprehensive
cosmological rest-frame reference, and the 21 cm hyperfine line, a spectroscopic reference for
redshift and motion across cosmological distances (since reionization carried mainly by neutral
hydrogen in and around galaxies). Neither generates time; both make its large-scale ordering
observable. Any observer can determine the cosmic time of their own stage from the local CMB
temperature, which falls in inverse proportion to the scale factor, and their motion relative to the
cosmological frame from the CMB dipole, about 370 km s⁻¹ for the Solar System. The question “which
stage of the cosmic present am I in” therefore has an operational answer, and the correction it
requires can be computed in practice: for SN1987A the difference between the cosmological-time
placement and the naive light-travel-time subtraction is at most about 200 years out of 168,000
(Appendix E). This establishes that CTGP’s present is physically well defined. It does not
discriminate CTGP from eternalism, which can use the same cosmic clock. That observers always find
their own present real is guaranteed under both readings, since every observation occurs at the
observer’s stage; it therefore confirms physical instantiation without bearing on ontological
exclusivity.
12.5 Summary of Empirical Standing
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Level | Claim | Empirical status
----------------+----------------------------------------------+-----------------------------------
Ontology | Only the present exists | Not observable (Proposition 12.1)
Structural | Fundamental laws are generable from the | Empirically exposed; refutable;
constraint | present (entailed by CTGP, merely permitted | consistent with current physics
| by eternalism) | (§12.2)
Physical | Generation law, couplings, and signatures of | Ordinary empirical hypotheses;
realization | σ | density-weighted forms excluded
| | (§11)
Three outcomes are possible for any physical realization of CTGP. If the added physics fails, as
density-weighted generation does, that refutes the realization, not the ontology. If the added
physics succeeds but is observationally equivalent to its rivals, CTGP is a physically coherent
formulation of presentism without experimental discrimination. If it succeeds and yields
observations its rivals do not naturally reproduce, the support runs along a chain: the observation
supports a physical theory, the theory supports objective becoming, and becoming lends indirect
support to presentism. At no step does an observation verify the ontology directly. CTGP does not
seek an experiment that detects the nonexistence of the past; it seeks a coherent realization of
objective becoming whose empirical consequences, if any, are carried by explicitly stated physics.
====================================================================================================
PART IV. Evaluation
====================================================================================================
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13. Objections and Replies
----------------------------------------------------------------------------------------------------
Objection O1 (Relativity of simultaneity): Presentism requires a global present, but SR denies
absolute simultaneity.
Reply: CTGP does not require an operationally absolute simultaneity relation between arbitrary
spacelike-separated events. It requires a foliation adequate for cosmology and compatible with GR's
initial-value structure. Cosmological time provides a physically grounded, non-absolute global
'now', which on large scales is the rest frame of the CMB — not a kinematic absolute but a physical
fact about our universe. The metaphysical claim concerns the ontological structure of M(σ), defined
by cosmological time, not the conventions individual observers use to label events as simultaneous
(§9.4).
Objection O2 (Lorentz invariance): Any preferred foliation violates Lorentz invariance.
Reply: A global foliation can be physically emergent while local laws remain Lorentz-invariant
(§9.3.1). Preferred frames in cosmology are properties of solutions, not new physics, and CTGP
predicts no preferred-frame effects on local physics, consistent with existing null results (§12.3).
Objection O3 (Diffeomorphism invariance): 'Growth' is a gauge artifact.
Reply: Growth is not a gauge artifact. The temporal ordering CTGP relies on begins from the causal
structure of spacetime itself: by the Hawking–King–McCarthy and Malament theorems, the causal
ordering relation already determines the conformal structure of the spacetime metric. Geroch and
Bernal–Sánchez then show that this causal ordering can be represented by smooth temporal functions
whose level sets are spacelike Cauchy hypersurfaces. CTGP does not introduce temporal ordering; it
selects a physically preferred representative of a class of orderings already latent in globally
hyperbolic GR. The representative is cosmological time, defined from the causal and metric structure
alone, which in cosmology coincides with the matter rest frame. The ontology is not a coordinate
artifact but a claim about causal structure. Equivalence classes under diffeomorphisms are
respected; the growth claim is made at the level of equivalence classes, not coordinate labels, and
cosmological time is preserved by isometries (Proposition 17.8).
Objection O4 (No empirical difference): CTGP is metaphysical over-interpretation.
Reply: CTGP does not claim that its ontology is observable: presentist and eternalist readings of
identical physics are observationally equivalent (§12.1). It is nonetheless empirically exposed
through the requirement that physical law be generable from the present, which can be refuted
(§12.2), and it makes commitments in the philosophy of mind that are not empirically neutral
(Appendix D).
Objection O5 (Infinite Regress of Laws): If σ governs the emergence of physical laws, what governs
σ? This threatens an infinite regress of meta-laws.
Reply: σ is not an emergent law requiring a further law to explain it but a primitive generative
structure, and explanatory chains may terminate in primitives without contradiction, as causal set
theory terminates at the partial order. The point is formalized by the Generative Minimality
Principle (Postulate 5) and the Primitive Generative Structure Principle (§10.4).
Objection O6 (What Is σ Defined Over?): If spacetime is not fundamental, what mathematical object
does σ live on? A scalar field requires a manifold; a manifold requires spacetime; but spacetime is
claimed to be emergent.
Reply: σ is not fundamentally a field over spacetime but an ordering parameter labeling generative
stages; at the pre-geometric level it orders a partially ordered set of stages without requiring a
manifold (§10.3). The continuum action of §9.1 is accordingly an effective low-energy description,
with the same status GR occupies within quantum gravity.
Objection O7 (Closed timelike curves): If spacetime admits closed timelike curves, a global Cauchy
foliation fails, and with it the generated present.
Reply: CTGP does not treat global hyperbolicity as a convenience: a solution with closed timelike
curves is a geometry that no sequence of generative stages could produce (§9.4.2). The known CTC-
admitting spacetimes — Gödel’s rotating dust universe, Tipler cylinders, and Kerr interiors beyond
the Cauchy horizon — are either inconsistent with observed cosmological boundary conditions or
idealizations that break down before the chronology-violating region is reached (§9.5). The
restriction is therefore physically motivated, and a confirmed observation of chronology violation
would falsify the framework (§12.3).
Objection O8 (Worldline perspective): Eternalists can explain temporal experience as a worldline
perspective within the block.
Reply: The worldline response succeeds only if the phenomenology of temporal experience is treated
as a representational illusion — a feature of how observers inside the block model their situation,
not of how things are. CTGP rejects this on the grounds developed in §§2.2 and 3: structure alone
does not amount to experience, and the felt asymmetry between past and future is a positive
constraint on ontology. The worldline perspective is descriptive and cannot say why any part of a
static manifold is accompanied by experience; CTGP supplies the architecture — active present-edge
processes, causal continuity, classicalization — within which that question can be posed (Appendix
D).