Concept

Natural Theology

Intro

Can you know anything about God just by looking at the world, without ever opening a Bible? Christians have traditionally said yes. The created order itself, the fact that anything exists at all, the way the universe is finely tuned, the moral sense built into every culture, points beyond itself to its Maker. That whole project of reasoning from the world to God is called natural theology.

The Bible itself authorizes the practice. Psalm 19 says "the heavens declare the glory of God." Romans 1 says God's "invisible attributes" can be "clearly seen" through what He has made, so clearly that no one has a real excuse for missing Him. Acts 17 shows Paul standing in front of a crowd of pagan philosophers and reasoning from creation and conscience straight into the resurrection.

Natural theology does not claim to do everything. It can get you to "there is a powerful, intelligent, moral Creator." It cannot get you, by reason alone, to the Trinity, the cross, or the resurrection. Those need God's direct revelation in Scripture and in Jesus. Natural theology is the front porch; Scripture takes you inside the house.

Different Christian traditions weigh the porch differently. Catholics and classical Protestants put heavy weight on it. The Reformed tradition tends to say belief in God is so basic to being human that you do not actually need a long chain of arguments to be rational in believing, the arguments are a bonus, not the foundation. Both views are represented in this codex.

The rest of this page traces the long history (Athanasius, Augustine, Aquinas's Five Ways, Paley's watchmaker, the modern revival in analytic philosophy), spells out exactly what natural theology can and cannot prove, and lays out the scriptural warrant that has kept the discipline going for two thousand years.

In full

The discipline of reasoning about God from premises available to human reason and observation of the natural world, apart from special revelation (Scripture). The Christian tradition has historically held that the existence and certain attributes of God can be known (with varying degrees of certainty and scope) through observation, reasoning, and reflection on the natural order, what theologians call general revelation (Romans 1:19-20; Psalm 19:1-3; Acts 14:17, 17:24-28), and that this knowledge is rationally accessible to all humans qua humans, regardless of whether they have heard the gospel.

Natural theology is the apologetic and philosophical activity of making explicit what general revelation reveals, formulating the inferences from creation to Creator into structured arguments that can be examined, tested, and defended. The codex houses these structured arguments in Arguments (the cosmological / teleological / ontological / moral / transcendental etc. families) and the underlying argumentative categories in Theist Arguments. This page is the meta-hub for the discipline as a whole, its history, its scope, its disputes, its place in the apologetic enterprise.

What natural theology claims (and does not claim)

Claims

The existence of God can be inferred from features of the natural world (the existence of contingent beings, the existence of order, the existence of moral consciousness, the existence of consciousness itself, etc.) by reasoning alone.
Certain attributes of God, necessity, aseity, immateriality, intelligence, power, goodness, can be inferred from the same observations.
The inference is rational, not merely emotional or volitional, it can be presented in syllogistic form, defended against objections, and assessed by the same standards used in other philosophical inquiry.
This natural knowledge is insufficient for salvific knowledge of God, it gets you to a deistic-or-theistic First Cause, not specifically to the Trinity, the incarnation, or the Cross. Saving knowledge requires special revelation (Scripture). But the natural knowledge is real knowledge as far as it goes, and it is part of what makes humans morally accountable before God (Romans 1.20, "so that they are without excuse").

Does NOT claim

That natural theology suffices to make a person a Christian. It does not. It gets you to theism; the gospel gets you to Christ.
That natural theology proves God's existence with mathematical certainty in a way no honest doubter could resist. Most natural-theology arguments are inductive or abductive (best-explanation) rather than strictly deductive, and reasonable people can resist any specific argument while remaining rational. The cumulative-case version (see Cumulative Case for Christian Theism) is much stronger than any single argument.
That natural theology is necessary for faith. Faith can arise from special revelation alone (Romans 10:17, "faith cometh by hearing, and hearing by the word of God"), and the Reformed Epistemology tradition (see Reformed Epistemology) argues belief in God is properly basic and does not require natural-theological argument to be warranted.

The proper claim: natural theology is one valid path to theistic belief, not the only path; it is part of the apologetic toolkit, not the whole toolkit.

The historical tradition

Patristic foundations

The early church fathers practiced natural theology informally, appealing to creation as testimony to the Creator, without yet developing systematic arguments. Athanasius (Contra Gentes 35-46, 4th century) reasoned from the order of creation to a single Creator-Mind. Augustine (Confessions X, City of God VIII, On Free Choice of the Will II) developed proto-cosmological and proto-ontological arguments. The patristic instinct was that creation itself testifies; the philosophical articulation was secondary.

Medieval flowering, Aquinas's Five Ways

The systematic high-water mark of natural theology is Thomas Aquinas, Summa Theologiae I.2.3 (c. 1265-1273), the celebrated Five Ways (Quinque Viae):

From motion, everything in motion is moved by another; this cannot regress infinitely; therefore an unmoved Mover (a cosmological argument; see Kalam Cosmological Argument and Cosmological Arguments for related modern descendants).
From efficient causation, every effect has a cause; this cannot regress infinitely; therefore a First Cause.
From contingency and necessity, contingent beings cannot account for their own existence; therefore a Necessary Being (see Necessary vs Contingent Being).
From degrees of perfection, observed degrees of goodness, truth, etc. presuppose a maximally perfect standard.
From design / teleology, natural things acting toward ends imply an Intelligence directing them (a teleological argument; see Teleological Arguments).

Aquinas's Five Ways are not five independent arguments so much as five faces of one underlying inference from features of creation to the existence of God. They have been refined, attacked, and defended continuously for 750 years and remain the most influential structured natural-theological corpus in the Christian tradition. The modern Cosmological-Argument family (Kalam Cosmological Argument, Leibnizian Contingency Argument) descends from Ways 1-3; the Teleological / Fine-Tuning family (Teleological Arguments, Fine-Tuning Argument) from Way 5; the Moral Argument family (Moral Arguments, Argument from Conscience) from a generalization of Way 4.

Modern restatements, Paley, the natural theologians of the 18th-19th centuries

William Paley, Natural Theology (1802), gave the famous watchmaker analogy: just as finding a watch on a heath would lead any rational observer to infer a watchmaker, the intricate organized complexity of biological organisms warrants the inference of a Designer. Paley's argument was the dominant natural-theological argument of the 19th century until Darwin's Origin of Species (1859) offered a naturalistic mechanism (cumulative natural selection) for the appearance of design, temporarily eclipsing the watchmaker argument.

The 20th-21st century revival of natural theology has been substantially the re-asking of the design question at levels Darwin did not address: cosmic fine-tuning, the origin of life and the genetic code, the origin of consciousness, the rational intelligibility of mathematics. See Laws of the Universe as Witness to Design, Intelligent Design, Fine-Tuning Argument, Information Argument for Design.

20th-century renaissance, analytic philosophy of religion

The mid-20th century saw a dramatic revival of natural theology in analytic philosophy, often called the Anglo-American analytic philosophy of religion:

Alvin Plantinga, God and Other Minds (1967); The Nature of Necessity (1974); Warranted Christian Belief (2000). Revived the Ontological Argument in modal form; developed Reformed Epistemology as the framework within which natural theology operates without being foundational.
Richard Swinburne, The Existence of God (Oxford, 1979; 2nd ed. 2004); The Coherence of Theism (1977; 2nd ed. 1993). Probabilistic Bayesian natural theology; the existence of God as the best explanation for the totality of evidence (cosmos + fine-tuning + consciousness + moral law + religious experience + historical revelation in Jesus).
William Lane Craig, The Kalam Cosmological Argument (Macmillan, 1979); Reasonable Faith (Crossway, 3rd ed. 2008). Revival of the Kalam from medieval Islamic philosophy (al-Ghazali) into rigorous contemporary form.
J. P. Moreland, Stephen Davis, Stephen Meyer, John Lennox, Robert Spitzer, others, continuing development of the cosmological, teleological, moral, consciousness-based, and information-theoretic arguments.

The Anglo-American renaissance has substantially reversed the mid-20th-century positivist assumption that natural theology was dead. As atheist philosopher Quentin Smith noted in 2001 ("The Metaphilosophy of Naturalism", Philo 4.2): "naturalists passively watched as realist versions of theism … began to sweep through the philosophical community, until today perhaps one-quarter or one-third of philosophy professors are theists, with most being orthodox Christians."

Scope of valid natural-theological inferences

Natural theology can plausibly establish (with varying degrees of strength):

God exists (cosmological / teleological / contingency arguments).
God is necessary, not contingent (modal cosmological and ontological).
God is immaterial (the cause of space and time cannot itself be spatial-temporal).
God is intelligent (the source of mathematical structure, biological information, fine-tuned constants is mind-like, not random-like).
God is morally significant (moral law presupposes a moral Law-giver).
God is unique / one (parsimony; multiple competing First Causes do not explain the unified cosmos).

Natural theology cannot establish from creation alone:

The Trinity, requires NT special revelation
The incarnation, requires special revelation
The atonement / penal substitution, requires special revelation
Specific doctrines of the inner life of God, requires special revelation
The plan of salvation, requires special revelation

The proper division of labor: natural theology gets you to theism (and perhaps to a theism with certain attributes); special revelation (Scripture, the church, the Spirit) gets you the rest. Natural theology + special revelation = Christian theology.

Reformed Epistemology, the in-house dispute about natural theology's role

A significant Reformed-tradition critique of natural theology (Karl Barth most famously; Cornelius Van Til in the presuppositional school; Alvin Plantinga in a different register) argues that natural theology either (a) fails because human reason is so corrupted by sin that it cannot reliably reason from creation to God, or (b) is unnecessary because belief in God is properly basic, formed directly by the sensus divinitatis in response to creation, without needing inferential argumentation to be warranted.

The Reformed-Epistemology variant (see Reformed Epistemology for the full treatment) does not deny the truth of natural-theological arguments; it argues they are not the foundation of warranted belief in God. Belief in God can be properly basic; arguments are useful supplements, especially in apologetic contexts where the unbeliever requests reasons.

The classical-Thomist response (in the contemporary period: Edward Feser, Ralph McInerny, others) defends the integrity of natural theology against Reformed-presuppositionalist critique: human reason is fallen but not nullified; the natural inferences from creation to Creator remain valid; the cumulative case in natural theology is part of what it means to be a rational creature in a rational creation. See Cumulative Case for Christian Theism for the contemporary reformed-evangelical-classical synthesis.

The codex holds both natural theology and Reformed Epistemology as compatible, complementary approaches.

The Scriptural warrant

Natural theology is not a philosophical imposition on Scripture; Scripture itself authorizes the practice:

Psalm 19:1-3, "The heavens declare the glory of God; and the firmament sheweth his handywork. Day unto day uttereth speech, and night unto night sheweth knowledge. There is no speech nor language, where their voice is not heard." Creation as continuous, universal natural revelation.
Romans 1.19-20, "Because that which may be known of God is manifest in them; for God hath shewed it unto them. For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse." The locus classicus for natural theology in Christian tradition. The natural knowledge of God is real, is culpable (renders unbelief inexcusable), and is inferential (the invisible is understood through the things that are made, the verb noeō, intellectually grasped).
Acts 14:16-17, Paul to the Lystrans: God "left not himself without witness, in that he did good, and gave us rain from heaven, and fruitful seasons, filling our hearts with food and gladness." Natural-theological appeal to providence and creation.
Acts 17:22-31, Paul to the Athenians (the famous Mars Hill speech). Paul reasons from natural theology (the altar to the unknown god, the providence of God, the unity of humanity, God's nearness to us) into the gospel proclamation (the resurrection of Jesus). The model of natural-theological apologetics in Acts.
Romans 2.14-15, the moral law written on Gentile hearts; the natural-theological grounding of the Moral Arguments family.
Hebrews 11.6, "he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him", the propositional minimum for which natural theology can provide the rational basis.

The Pauline pattern in Acts 17 is the apostolic warrant for the discipline. Christianity has done natural theology from its first generation.

Common questions this page answers

Q: What is natural theology?

The discipline of knowing God through reason and general revelation (the created order) apart from special revelation (Scripture); the classical natural-theology arguments (cosmological, teleological, moral, ontological) form the philosophical-apologetic core. Natural theology does not replace Scripture; it provides one set of resources for the case that the God of Christian faith exists.