Argument

Grounding Argument from Cognitivism

Intro

Here is a simple question that does a lot of work: is it true that torturing a child for fun is wrong, or is it just a feeling?

Most people, believers and atheists alike, answer "true." Not "true for me," not "I dislike it," but true, the way it is true that the earth goes around the sun. If you say that, you hold two positions philosophers have names for. You are a cognitivist (moral statements are the kind of thing that can be true or false) and a realist (some of them really are true, whatever anyone thinks).

This argument starts there and asks one follow-up question. Every true statement is true because of something. "The earth orbits the sun" is true because of the actual earth and the actual sun. So what makes "torturing a child for fun is wrong" true?

There are only four serious candidates on the table:

1. Human opinion or culture. It is wrong because we, or our society, say so.
2. A natural fact. It is wrong because it lowers well-being, a fact about brains and bodies.
3. A brute moral fact. It is wrong, full stop, and nothing further explains it.
4. God's nature. It is wrong because it is contrary to the character of a perfectly good God, in whose image the child is made.

The argument works by elimination. Opinion cannot be the ground, because then the torturer's culture could make it right, and you already said it is really wrong. Well-being cannot be the ground, because well-being gives the wrong answer in easy cases and cannot get from "this is what happens" to "this is what you must do." Brute facts cannot be the ground, because "it just is" explains nothing, a fact cannot command a person, and an atheist philosopher, Sharon Street, has shown that on evolution we would have no reason to think our moral beliefs track such facts anyway.

That leaves the fourth option. The goodness that makes the torture wrong is the goodness of God Himself.

The argument does not say atheists cannot be good, or cannot know right from wrong. Scripture says they can, because the law is written on every heart. It asks a narrower question: what makes moral truth true? On that question, the answers without God keep running out.

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In full

A deductive disjunctive syllogism for theism from the truth-aptness and truth of moral claims. P1 secures cognitivism plus realism by a paradigm case (gratuitous child torture). P2 applies a general truthmaker or grounding principle: contingent and necessary truths alike stand in an explanatory relation to what makes them so. P3 offers an exhaustive menu of grounds: mind-dependent (individual or collective attitude), naturalistic (descriptive facts such as well-being), non-naturalistic and non-theistic (sui generis moral facts with no further ground), and theistic (God's necessarily good nature, with obligation grounded in His commands). P4 to P6 eliminate the first three options. The conclusion follows by disjunctive syllogism.

The argument differs from the familiar two-premise Moral Argument in where it puts the pressure. The Craig form defends a conditional ("if God does not exist, objective moral values do not exist") in one block. This form unpacks that conditional into a menu and defeats each secular entry on its own terms, so the opponent must name which ground he holds before the exchange can continue. It is especially useful against secular realists such as Sam Harris, who share P1 and so cannot escape by retreating to relativism.

This page is structured as debate prep: diagnostic question first, a metaethics map so you know which position you are facing, per-premise affirmative case with steel-manned objections and 1:1 rebuttals, an honest-limits section, and a live-cite kit.

Argument structure

Form

Deductive disjunctive syllogism (A or B or C or D; not A; not B; not C; therefore D). The form is valid. Soundness turns on two things: whether the menu in P3 is complete, and whether each elimination holds. P4 and P5 are strong and most trained opponents concede them. P6 is where the serious secular realists (Erik Wielenberg, Russ Shafer-Landau, David Enoch) make their stand, and P3 is where a clever opponent will try to add a fifth option. Both are addressed below, and both are named honestly in the limits section.

The diagnostic question

Before you run the argument, find out who you are talking to. One question sorts almost everyone:

"Is it true that torturing a child for fun is wrong, or is it just a feeling?"

There are three branches.

1. "It's true." The person is a cognitivist realist. Good: P1 is granted and you have common ground. Move straight to P2 ("then something makes it true; what is it?") and walk the menu. Most secular realists will pick (b) well-being (the Harris line) or (c) brute fact (the Wielenberg line). Go to P5 or P6.
2. "It's just a feeling," or "it's an expression of disapproval." The person is a non-cognitivist. The argument does not start until P1 is secured, so switch tools. Press the cost: then "the Holocaust was evil" is not true either, it is only a shout of disgust, and "slavery was wrong" was no more correct in 1860 than "slavery is fine." Ask whether they really believe that, and whether they argue, reason, and protest as if they do. See Moral Anti-Realism Defeater.
3. "It's true for me," or "it's wrong in our culture." The person is a subjectivist or relativist. That is option (a), so P4 applies directly: if culture makes it wrong, a culture that approved of it would make it right. Ask whether a society that voted for child torture would be correct. See Subjective Morality Defeater and Intersubjective Morality Defeater.

Tactical note: do not argue with the person's answer before you have it. Ask, wait, then take the branch they chose. Most people pick branch 1, and the rest of this page is built for that branch.

Metaethics map

Metaethics asks what moral statements are and what, if anything, makes them true. The map below places every position you are likely to meet.

Non-cognitivism (moral statements are not true or false at all):

• Emotivism (A.J. Ayer, Language, Truth and Logic, 1936). "Stealing is wrong" expresses a feeling, roughly "Stealing, boo!" It states nothing.
• Prescriptivism (R.M. Hare, The Language of Morals, 1952). Moral statements are universal commands, like "Do not steal, and let everyone not steal." Commands are not true or false.
• Expressivism (the modern descendant, associated with Simon Blackburn and Allan Gibbard). Moral talk expresses attitudes or plans, with an elaborate account of why it sounds fact-stating.
• The standing problem for the whole family: moral statements behave logically like statements. "If lying is wrong, then getting your brother to lie is wrong; lying is wrong; so getting your brother to lie is wrong" is a valid argument. Feelings and commands do not combine that way. (This is the Frege-Geach problem.)

Cognitivism (moral statements are true or false):

• Realism (some moral statements are true, and their truth does not depend on anyone's attitudes):
  • Theistic realism. Moral truth is grounded in God's nature, with obligation grounded in His commands. This page's conclusion. See Divine Command Theory and Divine Simplicity.
  • Naturalist realism. Moral facts are natural facts, for example facts about well-being or human flourishing. Sam Harris holds a version of this.
  • Non-naturalist realism. Moral facts are real, objective, and irreducible to natural facts, with no further ground. Russ Shafer-Landau (Moral Realism: A Defence, 2003) and Erik Wielenberg (Robust Ethics, 2014). See Atheist Moral Realism Defeater.
• Error theory (J.L. Mackie, Ethics: Inventing Right and Wrong, 1977). Moral statements try to state objective facts, but there are no such facts, so every positive moral claim is false. Mackie was an atheist who judged objective values too strange to exist without God and so denied them.
• Subjectivism and relativism. Moral statements are true, but only relative to an individual's attitudes (subjectivism) or a culture's code (relativism).

Where this argument engages: P1 rules out non-cognitivism and error theory by the paradigm case. P4 rules out subjectivism and relativism. P5 and P6 rule out the two secular realisms. Theistic realism is what remains.

Common ground with Sam Harris

Sam Harris is a useful opponent for this argument precisely because he agrees with its first premise. In The Moral Landscape (2010) Harris argues that there are objective right and wrong answers to moral questions, that a religion endorsing cruelty is objectively mistaken, and that relativism is false. He is a cognitivist realist, not a relativist.

So the debate with a Harris-style opponent is not "is morality real?" Both sides say yes. The debate is "what grounds it?" Harris answers: facts about the well-being of conscious creatures, which science can in principle measure. That is option (b), and P5 addresses it directly. The full case against well-being as the ground, with ten concrete counterexamples, is in Well-Being Cannot Ground Morality Defeater.

Credit the agreement out loud. It changes the temperature of the conversation and narrows it to the one question that matters.

P1, Some moral statements are objectively true

Affirmative case

1. The paradigm case. Torturing a child for fun is wrong. Not unfashionable, not disliked, wrong. This proposition is more certain than any philosophical theory that would deny it. If a theory implies it is false, that counts against the theory.
2. We reason with moral statements. We infer from them, contradict them, and correct them. "You said lying is wrong, so you cannot lie to me now" is a valid argument. Only truth-apt statements behave this way.
3. Moral reform requires a fixed standard. We say abolition was progress, not mere change. Progress means getting closer to something true. Without moral truth, Wilberforce was not right and the slaveholders wrong; they simply disagreed.
4. Protest presupposes truth. The atheist who says the God of the Bible is cruel is making a moral claim he intends to be true, not reporting his mood.

Anticipated objections

1. "Moral claims are just expressions of emotion (Ayer)."
2. "There are no objective moral facts; all moral claims are false (Mackie)."
3. "Moral disagreement across cultures shows there is no moral truth."

Rebuttals

1. Emotivism cannot handle moral logic. The Frege-Geach problem: in "if lying is wrong, then getting your brother to lie is wrong," the clause "lying is wrong" expresses no feeling (the speaker may not be asserting it), yet the argument is valid. Emotivism also implies that "torturing children is wrong" and "torturing children is fine" do not contradict each other, which no one believes. Failure mode: a theory of meaning that cannot account for how the words are actually used.
2. Error theory trades a certainty for a theory. It asks us to believe that "torturing a child for fun is wrong" is false. That is less credible than any premise used to support error theory. Mackie himself judged that objective values would need something like God to explain them; he denied the values rather than accept God. That is a reason to take the values seriously, not a reason to deny them. Failure mode: the Moorean shift, giving up the more certain thing to keep the less certain one.
3. Disagreement does not show there is no truth. Cultures have disagreed about the shape of the earth and the cause of disease. Deep moral agreement (do not murder the innocent, keep faith, protect the weak) runs under the surface differences, and much disagreement is about facts (who counts as a person) rather than values. Failure mode: treating disagreement as proof of no fact of the matter.

Live-cite kit

• Scripture: Romans 2:14-15 (the work of the law written in the heart); Isaiah 5:20 (woe to those who call evil good).
• Scholarly: C. S. Lewis, Mere Christianity Bk I; J. Budziszewski, What We Can't Not Know (2003).
• Aphorism: "If it is only a feeling, then the child's torturer is not wrong. He just feels differently."

Tactical notes

• Get P1 granted out loud before anything else. Use the diagnostic question.
• If the opponent tries to change the example ("what about eating meat?"), bring it back. The argument needs only one objectively true moral statement.

P2, Objectively true statements have a ground

Affirmative case

1. Truth depends on reality. A true statement is true because of how things are. "Water boils at 100°C at sea level" is true because of water. Truth does not float free of what it is about.
2. The principle is not special pleading. We apply it everywhere else, in science, history, and law. Asking "what makes this true?" of a moral claim is asking the ordinary question.
3. Even secular realists accept a version of it. Harris gives a ground (well-being). Naturalist realists give a ground (natural properties). Only the non-naturalist says "no further ground," and P6 shows the cost.

Anticipated objections

1. "Some truths are basic and need no ground."
2. "Mathematical truths have no ground, and moral truths are like them."

Rebuttals

1. Basic truths still have something they are about. Even a basic truth is made true by its subject matter. The question is whether moral facts can be basic and binding and knowable, which is P6's subject. Failure mode: using "basic" to close a question that is still open.
2. The mathematics comparison helps the theist. Many philosophers, including theists from Augustine onward, locate necessary truths in the mind of God. And mathematical truths do not command anyone. "2+2=4" places no duty on you; "do not torture children" does. The comparison breaks exactly where morality is most distinctive. Failure mode: an analogy that leaves out obligation.

Tactical notes

• P2 is rarely contested in live debate. State it, give the water example, move on.

P3, The ground is opinion, a natural fact, a brute fact, or God's nature

Affirmative case

1. The four options map the field. Either the moral fact depends on minds or it does not. If on human minds, that is (a). If not on minds, then it is either a natural fact (b), a non-natural fact with no further ground (c), or grounded in a non-human mind and nature, God (d).
2. The standard secular theories sort into the menu. Subjectivism and relativism are (a). Contractarianism grounds morality in agreement, which is (a) at the collective level. Utilitarianism and Harris's view are (b). Wielenberg and Shafer-Landau are (c).
3. Hybrid views inherit the problems of their parts. A view that grounds morality partly in well-being and partly in brute facts must survive both P5 and P6.

Anticipated objections

1. "You've left out Kantian constructivism: morality is grounded in the structure of rational agency."
2. "You've left out ideal-observer theory: right is what a fully informed, impartial observer would approve."
3. "Maybe the ground is something no one has thought of yet."

Rebuttals

1. Constructivism falls into the menu. If "rational agency" is a natural fact about brains, it is (b) and faces the is-ought gap. If it is a normative fact about what reason requires, it is (c), a brute non-natural fact, and faces P6. Either way it does not escape. Failure mode: a new label on an old option.
2. The ideal observer is either hypothetical or real. If hypothetical, the ground is a counterfactual about human attitudes, which is (a) with idealization. If real, an all-knowing, impartial, perfectly good observer is a description of God. Failure mode: describing God and calling it secular.
3. An unspecified option is not an objection. The argument is a comparison of the live candidates. If the opponent has a fifth, he should name it, and then it can be tested. Until then, the elimination stands. Failure mode: treating "maybe something else" as a defeater.

Tactical notes

• When an opponent offers a "fifth option," ask one sorting question: "Does it depend on minds or not? Is it a natural fact or not?" Almost every proposal lands in (a), (b), or (c) within two questions.

P4, Not (a): opinion and culture collapse into relativism

Affirmative case

1. If opinion makes it wrong, opinion can make it right. If the wrongness of torturing a child is grounded in our disapproval, then a society that approved of it would make it right for them. That contradicts P1, which the opponent already granted.
2. Reformers become criminals. If culture defines right, then anyone who goes against the culture is wrong by definition. Martin Luther King Jr. and the abolitionists were moral offenders in their own societies.
3. Relativism is self-undermining. "Everyone ought to tolerate other cultures' morals" is itself a non-relative moral claim. The relativist needs at least one objective truth to state his view.

Anticipated objections

1. "It is grounded in human nature we all share, not in any one culture."
2. "It is grounded in agreement among rational people, not mere opinion."

Rebuttals

1. Shared human nature is a natural fact. That moves the view to option (b), and P5 applies. Failure mode: relabeling.
2. Agreement is still opinion, just more of it. If rational agreement makes torture wrong, then if rational people agreed otherwise, it would be right. If the reply is "rational people could never agree to that," then something other than agreement is doing the work, and that something is the real ground. See Intersubjective Morality Defeater. Failure mode: counting votes and calling the total a fact.

Live-cite kit

• Scripture: Isaiah 5:20; Proverbs 17:15 (justifying the wicked and condemning the righteous are both an abomination).
• Aphorism: "If culture makes it wrong, the right culture can make it right."

P5, Not (b): well-being cannot be the ground

Affirmative case

1. Well-being gives wrong verdicts. If right means "maximizes well-being," then harvesting one healthy patient's organs to save five is right, framing an innocent man to stop a riot is right, and secretly breaking a promise to a dying friend is right whenever the numbers favor it. We know these are wrong. The full list of ten cases is in Well-Being Cannot Ground Morality Defeater.
2. The is-ought gap (David Hume). "This act lowers well-being" describes what is. "You must not do it" prescribes what ought to be. No list of descriptive facts entails a prescription without adding a moral premise, here "you ought to maximize well-being." That premise is the thing that needed grounding. See Is-Ought Fallacy.
3. Defining good as well-being is not showing it. One can always ask, "this maximizes well-being, but is it good?" and the question is not empty. That is G. E. Moore's open-question test. If the question makes sense, "good" and "maximizes well-being" do not mean the same thing.
4. Knowing is not grounding. Frank Turek puts the distinction sharply against Harris:

The question is not what method should we use to discover what is moral, but what actually makes something moral? (Frank Turek, Stealing from God, PDF p. 110)

Anticipated objections

1. "Harris says well-being is as basic in ethics as logic is in reasoning. You cannot justify logic either."
2. "The counterexamples would lower well-being in the long run (fear of hospitals, collapse of trust)."
3. "Add rights and justice to well-being and the counterexamples disappear."

Rebuttals

1. The analogy fails on both sides. Rejecting logic is self-refuting; you must use logic to reject it. Rejecting well-being-maximizing is not; it is exactly what we do when we refuse to harvest the patient. And logic does not command. Calling well-being "axiomatic" admits it has not been grounded. Failure mode: an unjustified premise called an axiom.
2. Stipulate secrecy and the wrong remains. Make the organ harvest undetectable and the scapegoat's framing permanent. The long-run harms vanish, and the act is still wrong. So the wrongness was never about the long-run harms. Failure mode: answering a different case.
3. Adding rights concedes the point. If rights override well-being, then well-being is not the standard; the rights are, and they need their own ground. Failure mode: a hybrid whose load-bearing part is not well-being.

Live-cite kit

• Scripture: Romans 3:8 (Paul rejects "let us do evil, that good may come"); Genesis 9:6 (the individual's life protected because of the image of God, not because of totals).
• Scholarly: Hume, Treatise III.1.1; G. E. Moore, Principia Ethica (1903); Turek, Stealing from God (2014), ch. on morality; William Lane Craig vs Sam Harris (Notre Dame, 2011).
• Aphorism: "Science can tell you what will hurt someone. It cannot tell you that you must not."

Tactical notes

• Lead with one counterexample, not a list. The organ harvest is the cleanest. Ask "is it right?" and wait.
• When the opponent adds rights, say plainly: "Then we agree well-being is not the foundation. What grounds the rights?"

P6, Not (c): brute moral facts cannot be the ground

Affirmative case

1. Brute facts explain nothing. To say the wrongness of torture is a brute fact is to say there is no answer to "why is it wrong?" That is not a ground; it is the absence of one. Theism offers an explanation (the act violates the image of God and is contrary to God's goodness); brute realism offers a stop sign.
2. Facts do not obligate persons. An obligation is owed. It has authority over a will. An impersonal fact, however necessary, does not command anyone and is not someone to whom anything is owed. Persons bind persons. This is Robert Adams's point about obligation as a social, relational reality, and it is why the argument lands on a personal God rather than an impersonal principle.
3. The evolutionary debunking problem (Sharon Street). Street, an atheist, argues that if our moral beliefs were shaped by natural selection, they were shaped for survival and reproduction, not for tracking mind-independent moral facts. The realist then faces a dilemma. Either our moral beliefs do not track the facts (so we cannot know them, and realism loses its point), or they happen to track them (an unexplained coincidence). Street's own answer is to give up realism. Theism avoids the dilemma: the same God who is the standard of goodness made human minds to know it.
4. The queerness problem (J.L. Mackie). Mackie judged that objective moral facts would be strange entities, unlike anything else in a naturalist world, known by a strange faculty. He concluded there were none. The brute realist accepts the strangeness without explaining it.

Anticipated objections

1. "Brute moral facts are no worse than God being a brute fact."
2. "There are third-factor replies to Street (Wielenberg, Enoch)."
3. "Necessary truths do not need explanations."

Rebuttals

1. God is not a brute add-on. On classical theism God exists necessarily and is the one ultimate explanation for many things at once: the existence of the world, its order, minds, and moral truth. The brute realist adds a separate, unexplained layer of moral facts to a world that otherwise contains only matter and energy, and that layer explains nothing else. One explanation of many things beats many unexplained things. Failure mode: treating every stopping point as equal.
2. The replies remain contested inside the atheist camp. Street rejected Wielenberg's third-factor reply, and the debate is unresolved after two decades. The apologist does not need to win the technical exchange, only to note that the strongest atheist critic of realism does not think it has been answered. See Atheist Moral Realism Defeater. Failure mode: citing a reply as if it had settled the matter.
3. Even necessary truths can be grounded. The fact that something could not have been otherwise does not mean nothing explains it. Theists hold that necessary moral truths are grounded in God's necessary nature, which explains both their necessity and their authority. Failure mode: treating necessity as self-explaining.

Live-cite kit

• Scripture: Romans 2:14-15 (conscience as designed moral knowledge, the answer to Street's alignment problem); Genesis 1:27 (minds made in the image of the Knower).
• Scholarly: Sharon Street, "A Darwinian Dilemma for Realist Theories of Value," Philosophical Studies 127 (2006); J.L. Mackie, Ethics: Inventing Right and Wrong (1977); Robert Adams, Finite and Infinite Goods (1999).
• Aphorism: "Facts don't bind. Persons bind."

Tactical notes

• Street is the strongest single citation here because she is an atheist arguing from the opponent's own premises.
• Do not overclaim. Brute realism is not self-contradictory. The claim is that it explains less than theism and leaves obligation and moral knowledge without an account.

Conclusion

Therefore objective moral truth is grounded in God's nature. If P1 to P6 are true, the conclusion follows by disjunctive syllogism. The opponent must reject P1 (and say the child's torture is not really wrong), add a genuine fifth option to P3, or defend one of the three eliminated grounds against the objections above.

The conclusion is that God's nature is the ground, not His bare will. That distinction is what answers the Euthyphro dilemma.

The Euthyphro reply

The opponent will almost always ask: "Is something good because God commands it, or does God command it because it is good?" If the first, goodness is arbitrary. If the second, goodness is a standard above God.

The reply is that the dilemma is false. There is a third option, which is this argument's conclusion: goodness is grounded in God's nature, and obligation is grounded in His commands, which flow from that nature.

• God's commands are not arbitrary, because they express an unchanging, perfectly good character.
• Goodness is not above God, because it is God's character, not a standard He consults.
• The question "could God command cruelty?" has the answer no, for the same reason a triangle cannot have four sides. It would contradict what God is.

Turek states the third option directly:

God Himself is the unchanging standard of Good. The buck has to stop somewhere, and it stops at God's unchanging moral nature. (Frank Turek, Stealing from God, PDF p. 114)

And the dilemma cuts back. Every metaethic must stop somewhere. The brute realist stops at facts he cannot explain; the theist stops at a person who is goodness itself. The full treatment is in Euthyphro Dilemma Objection Defeater; see also Divine Command Theory and Divine Simplicity.

Honest limits

Know where the argument is weakest so you are not surprised in debate.

1. P3 completeness is the main vulnerability. The argument is only as strong as its menu. The sorting question ("mind-dependent or not, natural or not?") handles most proposed fifth options, but a sophisticated opponent can press views that resist sorting (some forms of constructivism, or quietist realism that refuses to say what grounds anything). The honest claim is that no known secular option escapes the menu, not that none ever could.
2. P6 is genuinely contested in professional philosophy. Russ Shafer-Landau defends non-naturalist realism carefully, holding that moral facts are sui generis and need no further ground, and he has replies to the queerness and debunking arguments. Wielenberg has a worked-out third-factor reply to Street. These views are not foolish. The theist's case against them is comparative: they leave obligation and moral knowledge less explained than theism does.
3. The argument establishes a personal, good, necessary ground, not the full Christian doctrine of God. Moving from that ground to the God of the Bible needs the wider case. See Christian God is the Only True God and Cumulative Case for Christian Theism.
4. The argument concerns grounding, not knowing or doing. It does not claim that atheists lack moral knowledge or moral lives. Romans 2:14-15 says the opposite.

Stating these limits openly makes the argument more credible, not less.

Master objections

1. "Atheists are just as moral as Christians." Reply: agreed, and the argument predicts it. The law is written on every heart. The question is not who behaves well but what makes good behavior good.
2. "This is a god-of-the-gaps argument." Reply: it is not built on what we do not know about nature. It is built on the logical gap between descriptive and prescriptive claims, which no future discovery of descriptive facts can close.
3. "Why God and not a Platonic Form of the Good?" Reply: an impersonal Form shares the problems of option (c). It cannot command, and it is not someone to whom obligations are owed. A personal ground fits obligation; an impersonal one does not.
4. "God's nature is just a brute fact too." Reply: see P6, rebuttal 1. A necessary, personal being that explains many things is a better stopping point than many unexplained moral facts that explain nothing further.
5. "The Bible contains commands I find immoral." Reply: that is a separate objection with its own treatment, and raising it presupposes the objective standard this argument is trying to ground.

Tactical opening / closing

Opening line: "Can I ask you something before we start? Is it true that torturing a child for fun is wrong, or is that just a feeling? Because if it's true, I'd like to ask what makes it true."

Closing landing strip: "We agree it's really wrong. We've looked at the four things that could make it wrong. Opinion can't, because then opinion could make it right. Well-being can't, because it tells us to harvest the patient. Brute facts can't, because they explain nothing and command no one. What's left is a good God whose image that child bears. That's not a gap in our knowledge. That's where the argument goes."

Connection to Scripture

Whoso sheddeth man's blood, by man shall his blood be shed: For in the image of God made he man. (Genesis 9:6, ASV)

• Genesis 9:6 grounds the wrongness of murder not in social cost or majority feeling but in what a human being is: the image of God. That is option (d) stated in a single verse. The prohibition is given to Noah, before Sinai and before Israel, so it binds all humanity.

(for when Gentiles that have not the law do by nature the things of the law, these, not having the law, are the law unto themselves; in that they show the work of the law written in their hearts, their conscience bearing witness therewith, and their thoughts one with another accusing or else excusing them); (Romans 2:14-15, ASV)

• Romans 2:14-15 explains why the diagnostic question works on almost everyone: moral knowledge is written on the heart, so people know P1 is true before they have a theory. It also answers Street's alignment problem: our moral faculties track moral truth because the Lawgiver wrote it there.
• Genesis 1:27, the image of God as the ground of human worth.
• Isaiah 5:20, "Woe unto them that call evil good, and good evil," against relativism.
• Micah 6:8, "He hath showed thee, O man, what is good," morality as revealed by a personal God.

Patristic / scholarly note

Patristic:

• Augustine reads Romans 2 as evidence that the moral law is God's handwriting in human nature:

For who but God has written the law of nature in the hearts of men? (Augustine, NPNF1 vol. 6, PDF p. 36)

• He ties that moral knowledge to the image of God, which sin damages but does not erase:

what was impressed on their hearts when they were created in the image of God has not been wholly blotted out (Augustine, anti-Pelagian writings, NPNF1 vol. 5, ch. 48, PDF p. 82)

Medieval: Aquinas, Summa Theologiae I-II q. 91 and q. 94: the natural law is the rational creature's participation in the eternal law, which is God's own reason.

Modern:

• Robert Adams, Finite and Infinite Goods (1999): the good grounded in God's nature, obligation in His commands.
• David Baggett and Jerry Walls, Good God (2011).
• William Lane Craig, Reasonable Faith (3rd ed., 2008), ch. on the moral argument.
• Frank Turek, Stealing from God (2014), the epistemology-ontology distinction against Harris.
• On the secular side: Sharon Street (2006), J.L. Mackie (1977), Russ Shafer-Landau (2003), Erik Wielenberg (2014), Sam Harris (2010).

See also

• Moral Argument, the classic two-premise form this argument unpacks
• Well-Being Cannot Ground Morality Defeater, the full case against option (b), with ten counterexamples
• Atheist Moral Realism Defeater, the full case against option (c)
• Moral Anti-Realism Defeater, for opponents who deny P1
• Subjective Morality Defeater and Intersubjective Morality Defeater, against option (a)
• Harm-Reduction Cannot Ground Morality (Defeater), the structural failures of harm-based ethics
• Euthyphro Dilemma Objection Defeater, the full Euthyphro reply
• Divine Command Theory, obligation grounded in God's commands
• Divine Simplicity, God's nature as goodness itself
• Argument from Conscience, the experiential side of moral knowledge
• Is-Ought Fallacy, the gap P5 depends on
• David Hume, source of the is-ought gap
• Sam Harris, the leading naturalist realist
• Sharon Street, the evolutionary debunking dilemma
• J.L. Mackie, error theory and the queerness argument
• Erik Wielenberg, the leading non-naturalist atheist realist
• Imago Dei, the anthropology behind Genesis 9:6
• Moral Arguments, parent hub
• Arguments, master index