The relationship between descriptive facts and normative judgments remains one of the most contentious issues in moral philosophy. HUME ON ‘IS’ AND ‘OUGHT’ challenges the conventional understanding of David Hume’s famous passage, revealing a more nuanced approach to moral reasoning that bridges empirical observations with ethical conclusions through human sentiments and shared interests. Rather than erecting an impenetrable barrier between facts and values, Hume’s actual position demonstrates how moral inferences operate through mediating concepts rooted in human nature—a insight that transforms our understanding of practical reasoning and ethical justification.
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Understanding the Traditional Interpretation of HUME ON ‘IS’ AND ‘OUGHT’
The conventional reading of Hume’s celebrated passage from Book III of the Treatise of Human Nature has dominated moral philosophy for decades. According to this interpretation, HUME ON ‘IS’ AND ‘OUGHT’ establishes an unbridgeable logical gap between descriptive statements about what “is” and prescriptive statements about what “ought” to be. Philosophers like R.M. Hare have even dubbed this principle “Hume’s Law,” treating it as a foundational prohibition against deriving moral conclusions from purely factual premises.
In Hume’s original text, he observes that moral treatises typically begin with factual observations—establishing God’s existence or making “observations concerning human affairs”—before imperceptibly shifting to moral conclusions expressed through “ought” statements. This transition, Hume notes, is “of the last consequence” because it seems “altogether inconceivable” how this new moral relation can be “a deduction from others, which are entirely different from it”.
However, this traditional interpretation has led to what A.C. MacIntyre identifies as a problematic formalism in ethics—treating moral reasoning as if it must conform to the strictures of deductive logic. Such formalism disconnects morality from human nature and reduces ethical arguments to categorical syllogisms devoid of sentiment and empirical grounding.
Reexamining HUME ON ‘IS’ AND ‘OUGHT’: MacIntyre’s Critical Analysis
MacIntyre’s groundbreaking reinterpretation reveals that HUME ON ‘IS’ AND ‘OUGHT’ has been fundamentally misunderstood. The conventional reading faces a crucial problem: if Hume truly prohibits deriving “ought” from “is,” then Hume himself violates this principle throughout his moral theory. Most notably, in his account of justice, Hume explicitly derives moral obligations from factual observations about human interests and social utility.
Consider Hume’s argument about justice: he demonstrates that the rules of justice are justified because “the whole plan or scheme is highly conducive, or indeed absolutely requisite both to the support of society, and the well-being of every individual”. This constitutes a clear derivation of normative conclusions (“we ought to follow just rules”) from factual premises (such rules promote general welfare). If the standard interpretation were correct, Hume would be committing the very error he supposedly condemns.
The Problem of Terminological Precision
MacIntyre’s analysis reveals a crucial oversight in the traditional interpretation: HUME ON ‘IS’ AND ‘OUGHT’ relies on misunderstanding Hume’s use of “deduction.” The conventional reading assumes Hume means logical entailment, but eighteenth-century usage employed “deduce” synonymously with “infer”. When Hume discusses formal logical relationships, he consistently uses “demonstrative arguments,” not “deduction.”
This terminological precision matters significantly. Hume’s concern is not with logical impossibility but with improper inference—warning against transitions from factual to moral statements without recognizing the mediating role of human sentiments and passions. The passage serves as a methodological caution rather than a metaphysical prohibition.
HUME ON ‘IS’ AND ‘OUGHT’ and the Role of Bridge Concepts
The reinterpreted HUME ON ‘IS’ AND ‘OUGHT’ reveals how moral reasoning actually operates through what we might call “bridge concepts”—intermediary notions that connect descriptive premises with normative conclusions. These concepts include desires, needs, interests, pleasure, pain, sympathy, and utility—all rooted in human psychology and social experience.
Hume’s moral theory demonstrates these bridge concepts throughout. In his account of justice, the transition from factual observations about social cooperation to moral obligations occurs through concepts like “common interest,” “mutual advantage,” and “public utility”. Similarly, his analysis of natural virtues like benevolence operates through sympathetic identification with others’ happiness and welfare.
Practical Reasoning and Motivational Force
HUME ON ‘IS’ AND ‘OUGHT’ illuminates Hume’s broader understanding of practical reasoning. Unlike purely formal logical systems, moral reasoning must connect with human motivations to generate action. As Hume famously argues, “reason is, and ought only to be the slave of the passions”. This principle explains why moral judgments require more than logical validity—they must engage with human sentiments and desires to produce behavioral outcomes.
The bridge concepts in HUME ON ‘IS’ AND ‘OUGHT’ serve precisely this function. When we argue “if you desire happiness, then you ought to act virtuously,” the concept of desire mediates between the factual claim about virtue’s effects and the normative conclusion about how to act. This structure preserves both logical coherence and motivational efficacy.
Justice and Artificial Virtues in HUME ON ‘IS’ AND ‘OUGHT’
Hume’s distinction between natural and artificial virtues provides crucial context for understanding HUME ON ‘IS’ AND ‘OUGHT’. Natural virtues like benevolence and courage spring directly from human sentiments and require no social conventions. Artificial virtues like justice, honesty regarding property, and promise-keeping arise through social processes designed to solve collective action problems.
Justice exemplifies how HUME ON ‘IS’ AND ‘OUGHT’ operates in practice. Hume argues that justice emerges because humans face “numberless wants and necessities” with “slender means” to satisfy them. Through gradual social learning, communities develop conventional rules that serve everyone’s long-term interests, even when individual just acts might be personally costly.
This account clearly derives normative obligations from factual premises about human nature and social conditions. The obligation to respect property rights follows from the empirical observation that such rules promote collective welfare and individual flourishing. The inference succeeds because it operates through bridge concepts like mutual advantage, social stability, and rational self-interest.
HUME ON ‘IS’ AND ‘OUGHT’ and Contemporary Moral Philosophy
The reinterpretation of HUME ON ‘IS’ AND ‘OUGHT’ has significant implications for contemporary debates in moral philosophy. Rather than supporting non-cognitivist theories that deny objective moral truth, Hume’s position suggests that moral judgments can be objective when properly grounded in human nature and empirical observations about welfare and flourishing.
This reading also challenges the strict fact-value distinction that has dominated modern ethics. While HUME ON ‘IS’ AND ‘OUGHT’ acknowledges important logical and methodological constraints on moral reasoning, it does not erect an absolute barrier between empirical and normative domains. Instead, it provides guidance for legitimate moral inferences through appropriate mediating concepts.
Implications for Practical Ethics
Understanding HUME ON ‘IS’ AND ‘OUGHT’ correctly transforms our approach to applied ethics. Rather than treating moral arguments as purely formal exercises, we can ground ethical reasoning in careful empirical observations about human psychology, social institutions, and the conditions for human flourishing. This approach avoids both crude naturalistic fallacies and excessive moral formalism.
For example, arguments about environmental ethics can legitimately move from factual claims about climate change to normative conclusions about policy obligations—provided they operate through appropriate bridge concepts like human welfare, intergenerational justice, and shared vulnerability. The key is ensuring that these inferences acknowledge their dependence on human values and sentiments rather than claiming purely logical necessity.
Variables in Hume’s Moral Framework
HUME ON ‘IS’ AND ‘OUGHT’ involves several key variables that mediate between factual observations and moral conclusions:
Sympathy: The psychological mechanism through which we share others’ sentiments and form moral judgments based on their effects on human welfare. Sympathy enables us to move beyond narrow self-interest to consider broader social consequences.
Utility: The principle that actions and institutions should be evaluated based on their contributions to human happiness and welfare. Utility provides a factual criterion for moral assessment while remaining grounded in human values and concerns.
Conventions and Customs: Social practices that emerge through collective experience and serve shared interests. These conventional arrangements bridge individual psychology and social morality by creating stable expectations and mutual obligations.
Passions and Desires: The motivational forces that drive human action and provide the ultimate basis for moral evaluation. Unlike pure reason, passions connect moral judgments with behavioral motivation, ensuring that ethics remains practically relevant.
Interpreting these variables correctly reveals how HUME ON ‘IS’ AND ‘OUGHT’ operates as a dynamic system linking empirical observations about human nature with normative conclusions about conduct and institutions.
HUME ON ‘IS’ AND ‘OUGHT’ Against Religious Morality
MacIntyre’s historical analysis reveals that HUME ON ‘IS’ AND ‘OUGHT’ originally targeted religious moral systems rather than moral reasoning in general. Hume’s critique focuses on “vulgar systems of morality”—the commonly accepted religious frameworks of his era that derived moral obligations from divine commands without adequate attention to human nature and welfare.
Consider Richard Allestree’s The Whole Duty of Man, a work Hume read in his youth. Allestree argues that God’s creation of humanity establishes absolute obligations of obedience, reasoning from the fact of divine creation to conclusions about moral duty. HUME ON ‘IS’ AND ‘OUGHT’ challenges such arguments not because they move from “is” to “ought,” but because they ignore the necessary mediating role of human sentiments and interests.
This interpretation explains Hume’s subsequent development of a naturalistic moral theory grounded in human psychology rather than divine authority. By replacing religious foundations with empirical observations about human nature, HUME ON ‘IS’ AND ‘OUGHT’ advances a more scientific approach to ethics.
The Historical Context of HUME ON ‘IS’ AND ‘OUGHT’
Understanding HUME ON ‘IS’ AND ‘OUGHT’ requires appreciating its place in the broader history of moral philosophy. MacIntyre argues that Hume represents a crucial turning point, defending the connection between morality and human nature against both religious authoritarianism and emerging Kantian formalism.
Medieval moral philosophy successfully integrated Aristotelian insights about human flourishing with Christian teachings about divine law. This synthesis grounded moral obligations in both human nature and divine authority, creating a coherent framework for practical ethics. The Protestant Reformation disrupted this synthesis by emphasizing human corruption and divine arbitrariness, severing the connection between natural inclinations and moral obligations.
HUME ON ‘IS’ AND ‘OUGHT’ attempts to restore this connection through empirical psychology rather than metaphysical argument. By showing how moral judgments arise from human sentiments and serve human interests, Hume provides a naturalistic foundation that avoids both religious dogmatism and moral skepticism.
HUME ON ‘IS’ AND ‘OUGHT’ and Modern Debates
The correct interpretation of HUME ON ‘IS’ AND ‘OUGHT’ illuminates contemporary philosophical disputes about moral realism, naturalism, and practical reasoning. Rather than supporting anti-realist positions that deny objective moral truth, Hume’s approach suggests that moral facts exist as features of human psychology and social organization.
This reading aligns with recent work by philosophers like Hilary Putnam, who challenges the strict fact-value distinction by showing how scientific reasoning itself involves evaluative commitments. Just as scientific theories are chosen based on values like simplicity and explanatory power, moral judgments can be objective when properly grounded in empirical observations about human welfare and flourishing.
HUME ON ‘IS’ AND ‘OUGHT’ also supports contextualist approaches to moral reasoning that emphasize the importance of particular circumstances and local knowledge. Rather than seeking universal moral principles valid across all contexts, Hume’s approach suggests that moral reasoning succeeds by attending carefully to specific human needs and social conditions.
Frequently Asked Questions
What is the “is-ought problem” in Hume’s philosophy?
The is-ought problem refers to the difficulty of deriving normative conclusions (what ought to be) from purely descriptive premises (what is). However, HUME ON ‘IS’ AND ‘OUGHT’ shows that Hume’s actual concern was with improper inferences that ignore the mediating role of human sentiments, not with logical impossibility.
Does Hume believe moral conclusions can never be derived from factual observations?
No. HUME ON ‘IS’ AND ‘OUGHT’ demonstrates that Hume regularly derives moral conclusions from empirical observations throughout his moral theory, particularly in his account of justice. His concern is methodological rather than metaphysical—ensuring that such inferences operate through appropriate bridge concepts.
What are “bridge concepts” in moral reasoning?
Bridge concepts are intermediary notions like desire, sympathy, utility, and shared interests that connect factual premises with normative conclusions. HUME ON ‘IS’ AND ‘OUGHT’ reveals how these concepts enable legitimate moral inferences while preserving logical coherence.
How does Hume’s position differ from modern non-cognitivism?
Unlike non-cognitivists who deny objective moral truth, HUME ON ‘IS’ AND ‘OUGHT’ grounds moral judgments in empirical facts about human nature and social welfare. While moral judgments express sentiments, they can be objectively correct or incorrect based on their relationship to human flourishing.
Why is the reinterpretation of Hume’s is-ought passage important?
The reinterpretation shows that HUME ON ‘IS’ AND ‘OUGHT’ supports naturalistic approaches to ethics that ground moral reasoning in human psychology and social science. This undermines excessive formalism and restores the connection between moral philosophy and empirical knowledge about human welfare.
What role do passions play in Hume’s moral theory?
Passions provide the motivational foundation for moral judgments and actions. HUME ON ‘IS’ AND ‘OUGHT’ shows how moral reasoning must engage with human desires and emotions to generate behavioral outcomes, explaining why purely rational approaches to ethics fail to motivate conduct.
How does Hume’s account of justice illustrate his approach to moral reasoning?
Justice exemplifies HUME ON ‘IS’ AND ‘OUGHT’ by deriving moral obligations from factual observations about social cooperation and mutual advantage. The rules of property and promise-keeping are justified because they serve collective welfare, showing how moral conclusions can emerge from empirical premises through appropriate mediating concepts.
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