Ad Hoc or Modus Ponens? Why Mind-First Reality Outperforms Naturalism
Abstract
Naturalism faces a recurring pattern: each major domain of evidence requires a distinct defensive maneuver. Cosmological fine-tuning invokes unobservable multiverses. The origin of biological information appeals to unspecified chemical processes across deep time. Consciousness is dismissed as illusion or deferred to future neuroscience. The reliability of reason itself is either assumed without justification or explained away as adaptive heuristic. These moves share a structure: they preserve the naturalist core by adding auxiliary hypotheses that resist empirical test. By contrast, a mind-first ontology (the view that rational mind is fundamental rather than derivative) generates these phenomena as natural entailments. Fine-tuning follows from intentional design. Information-rich biology follows from intelligent agency. Consciousness is native rather than anomalous. Reason is grounded rather than accidental. This paper argues that the comparison favors mind-first metaphysics on standard criteria of theory evaluation: empirical fit, explanatory unification, and parsimony at the level of fundamental commitments. Naturalism survives via modus tollens reversals, denying unexpected consequences to preserve prior commitments. Mind-first ontology proceeds by modus ponens, accepting what the evidence straightforwardly implies.
Keywords: naturalism, theism, fine-tuning, argument from reason, inference to best explanation, philosophy of science, ad hoc hypothesis
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1. Introduction
Scientific methodology prizes theories that predict rather than accommodate, that unify rather than fragment, that posit fewer fundamental entities rather than more. When a theory survives only by continually adding protective hypotheses to explain away anomalies, we grow suspicious. When it must invoke different escape routes for different domains, the suspicion deepens. The pattern suggests defensive maneuvering rather than robust explanation.
This paper examines whether metaphysical naturalism (the view that physical reality exhausts what exists) displays this pattern when confronted with the full range of evidence bearing on ultimate questions. The claim is not that naturalism is internally contradictory or that its defenders are intellectually dishonest. The claim is narrower and more testable: that naturalism’s survival strategy structurally resembles ad hoc hypothesis accumulation, while a mind-first alternative generates the same evidence as straightforward prediction.
The argument proceeds in three stages. First, the deductive core: naturalism faces a fundamental problem accounting for the necessary truths that make reasoning possible. Second, the inductive pattern: multiple independent domains of evidence (cosmological, biological, and phenomenological) converge on mind as explanatorily prior. Third, the abductive assessment: standard criteria of theory evaluation favor the ontology that unifies these domains under a single explanatory principle over the ontology that requires distinct protective moves for each.
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2. The Deductive Core: Reason, Necessity, and Self-Defeat
2.1 The Structure of the Problem
The target of this section is contingency-only physicalism: the view that all facts supervene on contingent physical arrangements and that no non-physical, non-contingent features of reality exist. Some philosophers who call themselves naturalists accept necessary truths as “ontologically lightweight” abstracta or as features of modal structure. Whether this remains naturalism in any substantive sense is doubtful; if necessary truths are real and constrain all possible physical configurations, they are not physical. Naturalists who embrace them have already conceded the central point: physical reality is not ontologically basic. The debate then concerns what grounds necessity, not whether it exists. The argument here addresses those who resist that concession.
Valid deductive inference is necessarily truth-preserving. This necessity is not psychological (how we feel compelled to reason), linguistic (how we happen to use logical terms), or merely descriptive (what inferences people typically draw). It is ontological: if the premises of a valid argument are true, the conclusion cannot be false. The “cannot” here expresses metaphysical impossibility, not practical difficulty.
This creates a problem for any metaphysics committed to the view that all facts are contingent physical facts. J.B.S. Haldane identified the tension early: “If my mental processes are determined wholly by the motions of atoms in my brain, I have no reason to suppose that my beliefs are true. They may be sound chemically, but that does not make them sound logically” (Haldane 1927, p. 209). The point is not that brain processes cannot implement reasoning (clearly they can); the point is that the validity of reasoning cannot be accounted for by appeal to physical causation alone.
C.S. Lewis developed this insight into what Victor Reppert calls “the argument from reason.” Lewis distinguished between two types of connection between mental events: cause–effect relations (one brain state producing another) and ground–consequent relations (one proposition logically entailing another). Naturalism can explain the former. It cannot explain the latter. “Even if grounds do exist, what exactly have they got to do with the actual occurrence of the belief as a psychological event?” (Lewis 1960, p. 25). Neural events have causes; valid inferences have grounds. Naturalism must either reduce grounds to causes (in which case validity becomes illusory) or acknowledge that something other than physical causation is operative in rational thought.
2.2 Plantinga’s Evolutionary Development
Alvin Plantinga extended this line of argument by focusing specifically on the conjunction of naturalism with evolutionary theory. His Evolutionary Argument Against Naturalism (EAAN) grants, for the sake of argument, that natural selection shaped human cognitive faculties. The question is whether faculties shaped for survival would also be reliable for truth.
Plantinga argues that the probability is either low or inscrutable: P(R|N&E), the probability that our cognitive faculties are reliable given naturalism and evolution, cannot be confidently assessed as high. Evolution selects for adaptive behavior, not true belief. If a belief produces survival-enhancing behavior regardless of its truth value, selection pressure is indifferent to its accuracy. The beliefs that “the tiger is dangerous” and “the tiger is a god requiring propitiation by flight” may produce identical behavior. Natural selection cannot distinguish them.
This generates a defeater. If the naturalist cannot trust that her cognitive faculties reliably produce true beliefs, she cannot trust the reasoning that led her to accept naturalism. The position undercuts itself. The problem is not direct contradiction; it is the removal of the epistemic ground on which the position stands (Plantinga 1993, ch. 12; 2011, chs. 10–12).
The EAAN has been contested. Fitelson and Sober (2007) challenge Plantinga’s probability assessments, arguing that natural selection may favor truth-tracking mechanisms more reliably than he allows. The debate continues. What matters for present purposes is that the Necessity Argument developed below does not depend on the EAAN’s probability claims. The Necessity Argument is logically prior: it concerns the preconditions of valid inference as such, not the reliability of evolved faculties. Even if the EAAN were successfully rebutted, the Necessity Argument would stand.
2.3 The Necessity Argument
Both Lewis’s and Plantinga’s arguments presuppose the framework I have elsewhere called the Necessity Argument Against Naturalism (Longmire 2026). The deeper problem is not merely that naturalism struggles to account for reliable cognition. It cannot account for the necessary truths that make cognition (reliable or otherwise) possible at all.
Deductive validity is a modal concept. To say that an inference is valid is to say that in every possible world where the premises are true, the conclusion is true. This involves necessary truth: the relation between premises and conclusion holds not contingently but essentially. If naturalism holds that all facts supervene on contingent physical arrangements, then there is no ontological space for necessary truth. Laws of logic would become cosmic accidents, true in this universe perhaps, yet lacking any deep sense of being binding.
The naturalist faces a dilemma. She can deny that logical truths are genuinely necessary, in which case her own arguments lose their binding force: they become reports of local regularity rather than demonstrations of what must be so. Or she can admit necessary truth into her ontology, in which case she has abandoned the core naturalist commitment that physical reality is all there is. Either horn undermines the naturalist project.
2.4 The Logical Priority
These three arguments (Lewis’s AFR, Plantinga’s EAAN, and the Necessity Argument) form a dependency hierarchy. The Necessity Argument is foundational: without necessary truth, there is no deductive validity; without deductive validity, there is no rational inference to evaluate for reliability. The AFR builds on this: it shows that even granting the apparatus of valid inference, naturalism cannot account for rational causation entering the physical order. The EAAN builds further: it shows that even granting both validity and rational causation, the specific mechanism of natural selection provides no assurance that our reasoning tracks truth.
Together they constitute a deductive case that naturalism is self-undermining. The naturalist cannot rationally affirm naturalism, because the resources required for rational affirmation are unavailable within a consistently naturalist framework. This is not a claim about psychology (naturalists can certainly feel confident); it is a claim about epistemology (that confidence lacks justification).
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3. The Inductive Pattern: Convergent Evidence for Mind
3.1 Cosmological Fine-Tuning
The physical constants and initial conditions of our universe fall within extraordinarily narrow ranges compatible with complex chemistry, stable stars, and embodied life. The cosmological constant is fine-tuned to roughly one part in 10^120. The gravitational constant, electromagnetic force, and strong nuclear force are balanced within tolerances that, if varied slightly, would preclude structure formation entirely.
Robin Collins provides the most comprehensive philosophical treatment of this evidence, arguing that fine-tuning confirms theism over naturalism by a likelihood ratio (Collins 2009). The intuition is straightforward: if a mind intended to create a universe capable of hosting other minds, we would expect precisely the kind of calibrated physics we observe. If no mind was involved, we would not expect it. The evidence confirms what theism predicts and disconfirms what naturalism predicts.
The standard naturalist response invokes a multiverse: if infinitely many universes exist with varying constants, then by selection effect we necessarily find ourselves in one of the rare life-permitting configurations. This move deserves scrutiny.
A distinction is warranted. Some multiverse proposals arise from independent theoretical work in inflationary cosmology and string theory; they are not invented solely to neutralize fine-tuning. Others are posited with no independent motivation. The latter are straightforwardly ad hoc. The former require more careful assessment.
Even theoretically motivated multiverse models face two problems. First, the universe-generating mechanism must itself be finely calibrated to produce a distribution of constants that includes life-permitting values. The fine-tuning problem recurs at a higher level. Second, even granting such a mechanism, the prior probability of mind-first ontology may still exceed that of an infinite unobserved cosmos. Parsimony at the level of fundamental commitments favors positing one purposive mind over infinitely many unobservable universes. The multiverse, whether theoretically motivated or not, does not clearly outperform mind-first metaphysics on standard criteria of theory choice.
3.2 Biological Information
The origin of life requires explaining the emergence of functionally specified information. DNA encodes instructions for building proteins using a symbolic system: sequences of nucleotides that bear no necessary physical relation to the amino acids they specify. Francis Crick’s “sequence hypothesis” recognized this: the nucleotide bases function like alphabetic characters conveying digital information (Crick 1958).
The information content of even the simplest self-replicating cell vastly exceeds what unguided chemistry can explain. Bill Gates observed that “DNA is like a computer program, but far, far more advanced than any software we’ve ever created” (Gates 1995). Richard Dawkins acknowledged that the genetic code is “uncannily computer-like” (Dawkins 1986, p. 17). The observation is common ground; the explanation is contested.
Stephen Meyer argues that intelligent agency is the only known cause of functionally specified information (Meyer 2009). Our uniform experience is that codes, languages, and programs originate from minds. The inference to intelligent design follows the same logic we employ when attributing meaning to archaeological inscriptions or extraterrestrial signals. If SETI researchers received a modulated signal encoding the first thousand prime numbers, they would conclude intelligence. They would conclude this without observing the sender, recognizing instead the causal signature of mind.
Naturalism responds with time and chance: given billions of years and vast combinatorial space, improbable configurations become inevitable. This response confuses two questions. Probability calculations over the relevant state space consistently yield values below the threshold of physical possibility; more combinations would be required than the universe contains elementary particle events. And crucially, the question is not whether a particular sequence could arise. The question is whether the functional constraints that define the sequence space can be met by random search. The target is not any arbitrary sequence; it is one of the vanishingly rare sequences that fold into functional proteins and coordinate into viable cells.
3.3 Consciousness
Thomas Nagel, himself an atheist, argues in Mind and Cosmos that “the materialist neo-Darwinian conception of nature is almost certainly false” (Nagel 2012, p. 3). His concern is philosophical rather than religious: materialism cannot account for consciousness, cognition, or value. This failure is not merely a matter of current ignorance; it is a matter of conceptual structure.
Consciousness presents the “hard problem”: how does subjective experience arise from objective physical processes? There is an explanatory gap between third-person descriptions of brain states and first-person awareness of phenomenal qualities. Nagel argues this gap is ontological rather than epistemological. It is not something we haven’t yet figured out; it is something that cannot be figured out within materialist premises. Physical theory deals in quantities, relations, and structures; consciousness involves qualities, meanings, and perspectives. The categories are incommensurable.
Naturalist responses follow familiar patterns. Eliminativists deny that consciousness exists as we naively conceive it, claiming phenomenal experience is illusion. Yet denying consciousness is self-defeating: the denial is itself a conscious judgment. Mysterians accept that consciousness is real but declare it inexplicable, a brute fact we must accept without understanding. Yet this is explanatory surrender, not explanation. Promissory materialists defer to future neuroscience. Yet deferral is not solution, and there are principled reasons (Nagel’s reasons) for thinking the solution cannot come from within materialism.
Mind-first ontology dissolves the problem. If mind is fundamental rather than derivative, consciousness is not something physical processes must somehow generate. It is native to reality at its base. Particular human consciousnesses emerge through physical embodiment, but the capacity for consciousness inheres in the fundamental nature of things. This is idealism or theism, distinct from dualism: mind is ontologically prior; matter is mind’s instrument or expression.
A note on alternatives: panpsychism and Russellian monism have gained traction as positions that take consciousness as fundamental while remaining non-theistic. These views share the crucial commitment that mind is not derivative from mindless matter. They belong on the mind-first side of the ledger. If a reader finds panpsychism more congenial than theism, the central thesis of this paper still stands: mind-first metaphysics outperforms mind-last naturalism. The primary contrast is between ontologies that treat mind as fundamental and those that treat it as emergent from or reducible to the non-mental. Strict physicalist naturalism loses that contest regardless of which mind-first alternative one prefers.
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4. The Abductive Assessment: Theory Evaluation Criteria
4.1 Empirical Fit
Both naturalism and mind-first ontology can accommodate the evidence surveyed above; that is precisely why they remain live options. The question is which accommodates it more naturally.
Naturalism accommodates fine-tuning by positing unobserved multiverses. It accommodates biological information by positing unobserved chemical precursors and vast timescales. It accommodates consciousness by denying it, deferring it, or declaring it inexplicable. Each accommodation is tailored to a specific domain. There is no unifying principle that predicts these diverse phenomena from naturalist premises.
Mind-first ontology predicts all three. An intelligent agent intending to create a universe hospitable to other minds would fine-tune the physics. An intelligent agent creating embodied creatures would encode their biological instructions symbolically. An intelligent agent creating beings in its own image would endow them with consciousness. The phenomena converge on a single explanatory principle: purposive mind is fundamental.
4.2 Explanatory Unification
Peter Lipton’s account of inference to the best explanation emphasizes that good explanations unify diverse phenomena under common principles (Lipton 2004). A theory that requires different mechanisms for different domains (with no principled connection between them) is explanatorily weaker than one that derives multiple phenomena from a single source.
Naturalism explains fine-tuning via multiverse physics, biological information via prebiotic chemistry, and consciousness via neuroscience. These are three independent research programs with no obvious theoretical connection. The multiverse has no implications for the origin of life; chemical evolution has no implications for phenomenal experience. The “explanations” are isolates.
Mind-first ontology derives all three from one source: an intentional, rational, conscious agent whose purposes include the existence of other intentional, rational, conscious agents. The fine-tuning sets the stage; the biological information provides the embodiment; the consciousness constitutes the goal. The explanatory unification is comprehensive.
4.3 Parsimony
Occam’s razor counsels against multiplying entities beyond necessity. Naturalists often invoke it against theism: why posit God when physics suffices?
The relevant parsimony, however, is not entity-counting at the surface level; it is parsimony at the level of fundamental commitments. Naturalism posits matter, energy, space, time, physical laws, and (to handle the evidence) unobserved multiverses, unspecified chemical precursors, and either eliminativism or promissory notes about consciousness. The list grows as anomalies accumulate.
Mind-first ontology posits mind as fundamental. Matter, energy, space, time, and physical laws are expressions or instruments of mind. The diversity of phenomena we observe flows from a single ontological commitment: purposive intelligence at the base of reality. This is more parsimonious at the level that matters: fewer unexplained explainers.
4.4 Ad Hoc versus Modus Ponens
The structural difference can be expressed logically. Naturalism proceeds by modus tollens when faced with evidence:
1. If naturalism is true, then we would not expect fine-tuning.
2. We observe fine-tuning.
3. Therefore… naturalism adds a multiverse hypothesis to block the inference.
The pattern repeats for each domain. The core commitment is protected by constructing auxiliary hypotheses that absorb the evidential impact. This is the hallmark of degenerating research programs (in Lakatos’s terminology): the protective belt grows while the core remains untested.
Mind-first ontology proceeds by modus ponens:
1. If purposive mind is fundamental, then we would expect fine-tuning.
2. We observe fine-tuning.
3. Therefore, evidence confirms purposive mind.
The same pattern holds for biological information, consciousness, and rational reliability. The evidence follows from the premises. No auxiliary hypotheses are needed. The core commitment generates the observations directly.
A clarification on “prediction”: the claim is comparative, not absolute. Mind-first ontology does not entail with probability 1 that a universe with fine-tuning, biological information, and consciousness must exist. A purposive mind could have created otherwise. The claim is that given the aim of creating rational, embodied agents, these features are robustly expected. The likelihood of the evidence given mind-first ontology with rational-creature-aims significantly exceeds the likelihood given naturalism. Bayesian confirmation does not require deductive entailment; it requires that the evidence be more expected under one hypothesis than under its rival. That condition is met.
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5. Objections and Replies
5.1 “This is God-of-the-Gaps Reasoning”
The objection misunderstands the argument’s structure. God-of-the-gaps reasoning invokes divine action to fill temporary ignorance, gaps that scientific progress might close. The present argument does not invoke God to explain what physics cannot yet explain. It argues that certain phenomena are in principle inexplicable on naturalist premises. The issue is not data we lack; it is conceptual resources that are unavailable.
The necessary truth required for valid inference is not a gap awaiting physical explanation; it is a category that physical explanation cannot address. The functional specificity of biological information is not a gap awaiting chemical explanation; it is a marker that our uniform experience attributes to minds. The subjective character of consciousness is not a gap awaiting neural explanation; it is a feature that neural explanation cannot reach.
5.2 “Science Requires Methodological Naturalism”
The objection conflates methodological and metaphysical naturalism. Methodological naturalism is a research heuristic: investigate physical causes for physical phenomena. This paper does not challenge that heuristic. Scientists should continue seeking natural explanations for natural events.
The target is metaphysical naturalism: the philosophical claim that physical causes are all there are. This is a worldview claim rather than a methodological commitment, and it is subject to philosophical evaluation. The argument here is that metaphysical naturalism fails standard criteria of theory evaluation when assessed against the full range of evidence.
5.3 “Theism Has Its Own Explanatory Gaps”
Granted. Mind-first ontology does not answer every question. Why does God permit evil? Why create through evolutionary processes? Why remain hidden?
These are questions about divine purposes rather than questions about conceptual coherence. The naturalist faces a different problem: the question is not “why would mind do this?” but “how could mindlessness produce this?” The former is a theological puzzle; the latter is a philosophical impossibility. It is better to have a puzzle than an impossibility.
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6. Conclusion
The argument of this paper is abductive, not demonstrative. It claims that mind-first ontology provides a better explanation of the evidence than metaphysical naturalism. It does not claim that naturalism is contradictory (though the self-defeat arguments approach that conclusion), nor that theism is proven beyond doubt.
The criteria applied are standard in philosophy of science: empirical fit, explanatory unification, parsimony at the level of fundamentals, and the distinction between theories that predict versus those that merely accommodate. By these criteria, naturalism displays the structure of a degenerating research program: it survives by adding protective hypotheses (multiverses, promissory chemistry, consciousness denial) that are tailored to specific anomalies and lack unifying theoretical motivation.
Mind-first ontology displays the opposite structure. It posits one fundamental reality, purposive mind, and derives the observed phenomena as natural consequences. Fine-tuning, biological information, consciousness, and rational reliability are not anomalies to be explained away; they are predictions to be confirmed.
The title’s disjunction is not merely rhetorical. Naturalism proceeds by modus tollens, reversing the implication when evidence threatens the conclusion. Mind-first ontology proceeds by modus ponens, affirming the consequent when evidence confirms the antecedent. The logical asymmetry reflects an explanatory asymmetry. One worldview accommodates; the other predicts. By the standards we apply to theories generally, prediction is superior to accommodation.
None of this compels belief. Philosophy rarely compels. Yet it shifts the burden. The naturalist can no longer claim default rational status. She must explain why her protective hypotheses are not ad hoc, why her promissory notes will be redeemed, why her denials of consciousness do not self-defeat. Until those explanations are forthcoming, mind-first ontology holds the field.
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