Does Erik Wielenberg's "robust ethics" argument succeed in establishing naturalistic objective moral values without God?

This question touches the core of contemporary debate in naturalistic moral philosophy. Erik Wielenberg — philosopher at DePauw University — presented in his book "Robust Ethics" (2014) and subsequent works an ambitious attempt to establish moral realism without recourse to God, claiming that moral facts can be "brute necessary facts" just like mathematical facts.

Inadequate responses to avoid

From some defenders of theism:

"No ethics without God, period." A doctrinal declaration, not a philosophical argument. Wielenberg presents detailed philosophical arguments that deserve a similar philosophical response, not a priori faith-based rejection. Even Craig and Plantinga — Wielenberg's strongest critics — treat his arguments with academic seriousness.

"Atheists cannot explain why we should be moral." Confusion between levels of inquiry. Wielenberg clearly distinguishes between moral ontology (what makes actions right/wrong?) and moral motivation (why should we care?). His argument focuses on the first level, and confusing them misses the debate.

"This is merely a restatement of ancient Platonism." Misleading reduction. Although Wielenberg benefits from Platonic intuition, he develops a sophisticated contemporary version that addresses problems Plato never faced, especially the issue of causal relationship between moral facts and the natural world.

From some naturalists:

"Wielenberg definitively proves that ethics doesn't need God." Overstatement. Wielenberg himself is more modest, claiming only to provide a "defensible option" for atheistic moral realism, not a decisive proof.

"Moral facts are exactly like mathematical facts." Oversimplification of Wielenberg's position. He uses the analogy with mathematics to clarify how non-natural facts can be objective, but acknowledges important differences between the domains, especially regarding moral knowledge.

Why these responses are inadequate

They fail to engage with the philosophical complexity of Wielenberg's position. His project is not merely "denying God's role in ethics," but an attempt to build a comprehensive metaphysical theory of objective ethics within a naturalistic framework, while seriously addressing known problems.

Structure of Wielenberg's central argument

Basic claim: There exist necessary moral facts irreducible to natural facts, but they don't need God to explain their existence or objectivity. These facts are "self-grounding" just as logical and mathematical facts are.

Mathematical analogy: Just as "2+2=4" is a necessary truth that doesn't need God to be correct (even according to most believers), so "torturing innocents for pleasure is wrong" is a similar necessary truth. The logical necessity of moral facts suffices for their objectivity.

"Making" mechanism: Wielenberg develops a relational concept of "making": natural properties make actions right or wrong through a necessary metaphysical relation, not causally. For instance: an action's "causing unjustified pain" makes it wrong by necessity, without needing divine mediation.

Addressing the matching problem: How do our moral intuitions match objective moral facts if no god designed them? Wielenberg suggests a "third factor solution": evolution shaped our cognitive capacities in ways that make us tend to perceive facts useful for survival, and basic moral facts (like the value of cooperation) are evolutionarily useful.

Strongest philosophical criticisms

Craig-Bignano criticism (2016): If moral facts are "brute necessary," why aren't all facts so? What specifically distinguishes moral facts to deserve this special status? Wielenberg responds that their normative nature distinguishes them, but this appears circular.

Mark Linville criticism (2018): Even if we accept the existence of necessary moral facts, the matching problem remains deeper than Wielenberg acknowledges. Evolution shapes behaviors useful for survival, not necessarily correct beliefs about abstract moral facts. The cosmic coincidence required for matching both seems statistically improbable.

Robert Adams criticism (updated 2019): Wielenberg's "making" relation remains metaphysically obscure. How do descriptive natural properties "make" normative facts without a metaphysical bridge? The known "is-ought gap" problem isn't solved by merely declaring a "necessary" relation.

David Baggett criticism (2017): Mathematical facts have "explanatory power" in natural sciences, while Wielenberg's moral facts appear "floating" without causal or explanatory role. This weakens the analogy with mathematics on which Wielenberg relies.

Sharon Street's updated criticism (2020): Even if Wielenberg succeeds in establishing moral objectivity, the "content" of this ethics remains undetermined. Which set of moral facts are "necessary"? Moral diversity across cultures points to a problem in determining content without transcendent reference.

Wielenberg's defenses and developments

In his responses (2016-2020), Wielenberg developed several lines of defense:

First, the "parity with theology" argument: even theists face a similar problem — why is God necessarily good? If the answer is "his nature," why isn't the nature of moral facts themselves sufficient?

Second, developing "evolutionary moral epistemology": what's required isn't complete matching between our intuitions and moral facts, but sufficient capacity to perceive basic facts related to survival and flourishing.

Third, the "best explanation argument": robust moral realism explains moral phenomena (moral progress, apparent objectivity, the force of duty) better than alternatives, whether subjectivist or theistic.

The deeper criticism: the problem of metaphysical foundation

Even those sympathetic to Wielenberg's project (like David Enoch and Russ Shafer-Landau) point to a fundamental problem: saying moral facts are "brute necessary" appears to stop the question rather than answer it. The logical necessity of mathematical facts has a foundation in the structure of rational thought itself, while the necessity of moral facts needs a deeper metaphysical foundation.

Contemporary critical assessment

The philosophical consensus (according to PhilPapers 2020 survey) is divided:
- 26% see Wielenberg as providing a defensible option
- 31% see the metaphysical problems as fatal
- 43% undecided or preferring other approaches

Most striking: even among atheist philosophers, there's sharp division about the viability of Wielenberg's project, with many leaning toward other forms of moral naturalism (like reductivism or constructivism).

From the perspective of rational weighing (rajḥān ʿaqlī) (site methodology)

Wielenberg's attempt represents the strongest offering from contemporary naturalism in the field of moral realism. On one hand, its success in:
- Providing a logically coherent framework for objective ethics without God
- Serious treatment of the most important traditional problems
- Developing innovative metaphysical concepts

On the other hand, its failures in:
- Providing a convincing metaphysical foundation for moral necessity
- Satisfactorily solving the matching problem
- Explaining the specific content of moral facts

Rational weighing suggests that Wielenberg didn't so much "fail" as reveal the depth of the philosophical challenge. His project demonstrates both the sophistication possible within naturalistic moral realism and its ultimate limitations in providing what Adams calls "metaphysical foundations deep enough" for robust moral objectivity.

Where we stand in this debate today

Between 2020 and 2026, the debate around "robust ethics" has developed in several directions. Wielenberg himself continued developing his position in articles and debates with Craig and Baggett, focusing on strengthening the mathematical analogy and expanding the "third factor" theory in evolutionary epistemology. Meanwhile, a new wave of criticism emerged: philosophers like Tyler Hagendorff and Josh Rasmussen developed arguments linking the moral grounding problem to the broader metaphysical grounding problem, showing that "brute necessary facts" face similar difficulties in both domains. The PhilPapers 2020 survey confirmed that moral realism enjoys majority support among philosophers (62%), but there's sharp division over whether it needs a transcendent metaphysical foundation. The notable trend in recent literature is declining confidence in the adequacy of "brute facts" as ultimate answers, with growing interest in constructivist approaches on one hand, and updated theistic approaches on the other. The debate hasn't been settled, but Wielenberg's project has become a mandatory reference for any party entering this field — whether to build upon it or criticize it.