In his original essay, The Form of Practical Knowledge, Stephen Engstrom argues for placing Kant’s ethics in the tradition of practical cognitivism. My remarks are intended to highlight the merits of his interpretation in contrast to intuitionism and constructivism, understood as ways of appropriating Kant’s legacy. In particular, I will focus on two issues: first, the special character of practical knowledge—as opposed to theoretical knowledge and craft expertise; and second, the apparent tension between the demands of morality and the requirements (...) of instrumental reason, when this is understood as driven by concerns for happiness, prudence, and personal integrity. (shrink)

One of the most familiar arguments for expressivist metaethics is the claim that the rival theory, moral realism, cannot provide a satisfying explanation of why moral properties supervene on natural properties. Non-cognitivism, however, has its own problems explaining supervenience. Expressivists try to establish supervenience either by second-order disapproval of type-inconsistent moral evaluations or by pragmatic considerations. But disapproval of inconsistency is merely a contingent attitude that people happen to have; and pragmatic justification does not allow for appraisers to take their (...) own moral attitudes seriously enough. What has been overlooked is a third alternative. The metaethical theory that can best account for supervenience is neither realist nor non-cognitivist but an objectivist version of constructivism. On the constructivist theory, right and wrong are determined by the principles that people would (hypothetically) consent to under ideal conditions. Type-consistency is a required feature of any principles regulating our conduct, if they are to be freely agreed to by ideally rational people. (shrink)

In the Foundations of the Metaphysics of Morals Kant presented a method for discovering what morality requires us to do in any situation and claimed that it is a method everyone can use. The method consists in testing one's maxim against the requirement stated in the formulations of the categorical imperative. There has been endless discussion of the adequacy of Kant's method in giving moral guidance, but there has been little effort to situate Kant's view of ethical method in its (...) historical context. In this paper I try to do so. I take the label "method of ethics" from the work of Henry Sidgwick. A method of ethics, he says, is any rational procedure by which we determine what it is right for an individual to do or what an individual ought to do. Since the moralists I want to consider do not all think of morality as rational, I shall broaden the notion by saying that a method is any systematic or regular procedure, rational or not, by which we determine what morality requires... (shrink)

In this paper I trace the development of one of the central debates of late twentieth-century moral philosophy—the debate between realism and what Rawls called “constructivism.” Realism, I argue, is a reactive position that arises in response to almost every attempt to give a substantive explanation of morality. It results from the realist’s belief that such explanations inevitably reduce moral phenomena to natural phenomena. I trace this belief, and the essence of realism, to a view about the nature of concepts—that (...) it is the function of all concepts to describe reality. Constructivism may be understood as the alternative view that a normative concept refers schematically to the solution to a practical problem. A constructivist account of a concept, unlike a traditional analysis, is an attemptto work out the solution to that problem. I explain how the philosophies of Kant and Rawls can be understood on this model. (shrink)

The goal of the following paper is to consider the development and viability of Korsgaard’s latest work, Self-Constitution. More specifically, I show that we should understand this book as a response to difficulties with both Korsgaard’s argument in 1996’s The Sources of Normativity and Korsgaard’s earlier attempts to explain what marks the difference between realist and constructivist approaches to ethical theory. I begin by focusing primarily on her essay “Realism and Constructivism in Twentieth-Century Moral Philosophy.” Here I consider exactly how (...) Korsgaard defines constructivism and what makes constructivism different from realist approaches to ethics. I then examine Korsgaard’s two most influential books – Sources and Self-Constitution – in light of this definition. Looking at Sources I argue that there is a serious problem with Korsgaard’s attempt to develop a constructivist moral theory; more specifically, I expose a tension in Korsgaard’s claim that ethical concepts both are rooted in a philosophy of action and exist only as the solution to a concrete practical problem. I then turn to Self-Constitution. I show that a different account of the distinction between realism and constructivism is proposed, one that not only seems designed to avoid the problems that plagued Sources but also forces Korsgaard to significantly revise and retreat from earlier attempt to distinguish constructivism from realism. Finally, I argue that obstacles remain for even this more moderate account. -/- . (shrink)

Constitutivism is the view that it is possible to derive contentful, normatively binding demands of practical reason and morality from the constitutive features of agency. Whereas much of the debate has focused on the constitutivist's ability to derive content, David Enoch has challenged her ability to generate normativity. Even if one can derive content from the constitutive aims of agency, one could simply demur: ?Bah! Agency, shmagency?. The ?Why be moral?? question would be replaced by the ?Why be an agent?? (...) question. It is the aim of this paper to show that the shmagency objection is essentially correct, though not as originally defended by Enoch. Since Enoch posed his argument as ruling out the normative authority of agency under any conception of the constitutive features of agency, constitutivists have responded by arguing for the inescapability of certain minimal features of agency. I argue that this amounts to equivocation: the constitutivist appeals to a minimal conception of agency in answering the normative question but to a richer understanding in answering the content question. The key to the shmagency objection, as I shall defend it, is to insist that the same sense of agency must be employed in answering both questions. A shmagent can concede that there may be inescapable ways of understanding agency, but insist that any such understanding would have to be too minimal to generate substantive content. (shrink)

Onora O'Neill; I *—The Presidential Address: Constructivisms in Ethics, Proceedings of the Aristotelian Society, Volume 89, Issue 1, 1 June 1989, Pages 1–18, ht.

This essay addresses the relationship between Kant's theory of moral motivation and theories of normativity. Constructivist or "ideal agent" theories of normativity claim that what makes a principle normative is that rational agents endorse or possess a motive of a certain kind to comply with it, or that they endorse or possess such a motive to comply with it insofar as they are rational. Korsgaard has argued that Kant's "motivational analysis" of the concept of obligation in Grundlegung I provides an (...) argument for such a constructivist theory of normativity. In this examination of Korsgaard's argument, I defend two important modifications of the concept of "intrinsic normativity" and suggests that once these modifications are made, the motivational analysis argument fails to establish the constructivist claim that the normative authority of the supreme principle of morality is constituted by or depends solely upon agents' motivational states. While Kant's motivational analysis helps to reveal the nature of the alleged internal relation between the supreme principle of morality and the nature of the rational will, it does not demand the adoption of a constructivist theory of normativity. (shrink)

It is often argued that future-directed decisions are effective at shaping our future conduct because they give rise, at the time of action, to a decisive reason to act as originally decided. In this paper, I argue that standard accounts of decision-based reasons are unsatisfactory. For they focus either on tie-breaking scenarios or cases of self-directed distal manipulation. I argue that future-directed decisions are better understood as tools for the non-manipulative, intrapersonal division of deliberative labor over time. A future-directed decision (...) to ϕ gives rise to a defeasible exclusionary reason to ϕ. This reason is grounded on the default authority that is normally granted to one’s prior self as an “expert” deliberator. I argue that this kind of exclusionary reason is the only one that can account for the effectiveness of future-directed decisions at shaping our diachronic agency without violating our autonomy over time. (shrink)

The dominant interpretation of Kant as a moral constructivist has recently come under sustained philosophical attack by those defending a moral realist reading of Kant. In light of this, should we read Kant as endorsing moral constructivism or moral realism? In answering this question we encounter disagreement in regard to two key independence claims. First, the independence of the value of persons from the moral law (an independence that is rejected) and second, the independence of the content and authority of (...) the moral law from actual acts of willing on behalf of those bound by that law (an independence that is upheld). The resulting position, which is called not ‘all the way down’ constructivism, is attributed to Kant. (shrink)

13. The Normative Thoughts of Neighborly Love, Part 1.

The article offers an account of the constructivist methodology in ethics and political philosophy as 1) deriving from an agnostic moral ontology and 2) proposing intersubjective justifiability as the criterion of justification for normative principles. It then asks whether constructivism, conceived in this way, can respond to the challenge of “content skepticism about practical reason”, namely whether it can provide sufficiently precise normative guidance whilst remaining faithful to its methodological commitment. The paper critically examines to alternative way of meeting this (...) challenge, namely John Rawls's original position and O'Neill's Kantian constructivism, analyses what is problematic about both, and endorses a third, possibly intermediate model. Within such a model, the basic features of the original position are accepted, but in a flexible and heuristic manner, thereby accommodating some of O'Neill's concerns. (shrink)

It is often debated whether what we ought, politically, to do is determined by standards that are independent of any actual political process or whether, by contrast, judgments reached in actual democratic processes have constitutive importance in determining what we should do. This paper argues that this is not an exclusive disjunction and that, consistently with there being independent standards, constitutively authoritative judgments can enter into the truth-conditions pertaining to claims about what we ought, politically, to do. The crucial objection (...) to constitutive judgment is that it involves an unacceptable form of bootstrapping, according to which reasons arise out of nothing. To circumvent this objection, the paper deploys John Broome's notion of a wide-scope 'normative requirement'. Normative requirements affect what ought to be done without altering the balance of reasons and defuse the bootstrapping objection by blocking the derivation of all-things-considered conclusions. To show that politics involves constitutive authority of this kind, the paper defends two illustrative normative requirements applicable to the political process that give constitutive roles to political judgments of various kinds. Throughout, the discussion is enlivened by comparisons to the judgments of a baseball umpire, which have been illuminatingly discussed by Robert Brandom. (shrink)

. This paper questions nearly every major point Christina Lafont makes about “the validity of social norms” and their relation to moral realism and Kantian constructivism. I distinguish realisms from theories of objective or subjective knowledge, then from cognitivism. Next, I distinguish Kant and constructivism from Rawls' political constructivism. Finally, I propose clues for an alternative theory of moral constructivism.

(No abstract is available for this citation).

More and more people seem to think that constructivism - in political philosophy, in moral philosophy, and perhaps in practical reasoning most generally - is the way to go. And yet it is surprisingly hard to even characterize the view. In this paper, I go to some lengths trying to capture the essence of a constructivist position - mostly in the realm of practical reason - and to pinpoint its theoretical attractions. I then give some reason to suspect that there (...) cannot be a coherent constructivist view about practical reason as a whole, at least not if it is to be interestingly constructivist, in a sense I make reasonably precise. (shrink)

In the contemporary metaethical debate, expressivist (Blackburn, Gibbard) and constructivist (Korsgaard, Street) views can be viewed as inspired by irrealist ideas from Hume and Kant respectively. One realist response to these contemporary irrealist views is to argue that they are inconsistent with obvious surface-level appearances of ordinary ethical thought and discourse, especially the fact that we talk and act as if there is ethical knowledge . In this paper, I explore some constructivist and expressivist options for responding to this objection. (...) My conclusion is that, although both constructivists and expressivists can capture other surface-level features of ethical thought and discourse, the possibility of ethical knowledge causes special problems for these versions of irrealism. I end with some comments about where I think irrealists should begin to look for a response to these special problems, which points, somewhat surprisingly, towards an alternative inferentialist form of irrealism about epistemic and ethical thought and discourse, which is inspired by Sellars. (shrink)

This essay argues that normative judgments, in general, and moral judgments, in particular, are "truth apt" and can be objects of belief. Other main claims are: judgments about reasons, if interpreted as true, do not have metaphysical implications that are incompatible with a scientific view of the world. Two kinds of normative claims should be distinguished: substantive claims about what reasons people have and structural claims about what attitudes people must have insofar as they are rational. Employing this distinction, the (...) practical significance of substantive normative judgments is explained, and critical analysis of expressivist and Kantian views on this question is offered. (shrink)

Most agree that when it comes to so-called 'first-order' normative ethics and political philosophy, constructivist views are a powerful family of positions. When it comes to metaethics, however, there is serious disagreement about what, if anything, constructivism has to contribute. In this paper I argue that constructivist views in ethics include not just a family of substantive normative positions, but also a distinct and highly attractive metaethical view. I argue that the widely accepted 'proceduralist characterization' of constructivism in ethics is (...) inadequate, and I propose what I call the 'practical standpoint characterization' in its place. I then offer a general taxonomy of constructivist positions in ethics. Since constructivism's standing as a family of substantive normative positions is relatively uncontested, I devote the remainder of the paper to addressing skeptics' worries about the distinctiveness of constructivism understood as a metaethical view. I compare and contrast constructivism with three other standard metaethical positions with which it is often confused or mistakenly thought to be compatible: realism; naturalist reductions in terms of an ideal response; and expressivism. In discussing the contrast with expressivism, I explain the sense in which, according to the constructivist, the distinction between substantive normative ethics and metaethics breaks down. I conclude by distinguishing between two importantly different debates about the mind-dependence of value. I argue that a failure to make this distinction is part of what explains why the possibility of constructivism as a metaethical view is often overlooked. (shrink)

Some commentators have attributed constructivism to Kant at the first-order level; others cast him as a meta-ethical constructivist. Among meta-ethical constructivist interpretations I distinguish between ‘atheistic’ and ‘agnostic’ versions regarding the existence of an independent moral order. Even though these two versions are incompatible, each is linked with central Kantian doctrines, revealing a tension within Kant's own view. Moreover, among interpretations that cast Kant as rejecting substantive realism but embracing procedural realism, some (i.e., those that are ‘constructivist’) face charges of (...) indeterminacy or relativism, while others (practical reasoning views) face ‘daunting rationalism’ objections. I close with some objections to interpreting Kant as a meta-ethical constructivist. (shrink)

Christine M. Korsgaard is one of today's leading moral philosophers: this volume collects ten influential papers by her on practical reason and moral psychology ...

Agency and identity -- Necessitation -- Acts and actions -- Aristotle and Kant -- Agency and practical identity -- The metaphysics of normativity -- Constitutive standards -- The constitution of life -- In defense of teleology -- The paradox of self-constitution -- Formal and substantive principles of reason -- Formal versus substantive -- Testing versus weighing -- Maximizing and prudence -- Practical reason and the unity of the will -- The empiricist account of normativity -- The rationalist account of normativity (...) -- Kant on the hypothetical imperative -- Against particularistic willing -- Deciding and predicting -- Autonomy and efficacy -- The function of action -- The possibility of agency -- Non-rational action -- Action -- Attribution -- The psychology of action -- Expulsion from the garden : the transition to humanity -- Instinct, emotion, intelligence, and reason -- The parts of the soul -- Inside or outside -- Pull yourself together -- The constitutional model -- Models of the soul -- The city and the soul -- Platonic virtues -- Justice : substantive, procedural, and platonic -- Kant and the constitutional model -- Defective action -- The problem of bad action -- Being governed by the wrong law -- Or five bad constitutions -- Conceptions of evil -- Degrees of action -- Integrity and interaction -- Deciding to be bad -- The ordinary cases -- Dealing with the disunified -- Kant's theory of interaction -- My reasons -- Deciding to treat someone as an end in himself -- Interacting with yourself -- How to be a person -- What's left of me? (shrink)

This paper criticizes two accounts of the normativity of practical principles: the empiricist account and the rationalist or realist account. It argues against the empiricist view, focusing on the Humean texts that are usually taken to be its locus classicus. It then argues both against the dogmatic rationalist view, and for the Kantian view, through a discussion of Kant's own remarks about instrumental rationality in the second section of the Groundwork. It further argues that the instrumental principle cannot stand alone. (...) Unless there are normative principles directing us to the adoption of certain ends, there can be no requirement to take the means to our ends. The familiar view that the instrumental principle is the only requirement of practical reason is incoherent. (shrink)

1. The Shmagency Challenge to Constitutivism In metaethics – and indeed, meta-normativity – constitutivism is a family of views that hope to ground normativity in norms, or standards, or motives, or aims that are constitutive of action and agency. And mostly because of the influential work of Christine Korsgaard and David Velleman, constitutivism seems to be gaining grounds in the current literature. The promises of constitutivism are significant. Perhaps chief among them are the hope to provide with some kind of (...) answer to the skeptic about morality or perhaps practical reason, and the hope to secure for practical reason a kind of objectivity that is consistent with its practical, motivationally engaged nature. The former philosophical motivation for constitutivism – most clearly present in much of Korsgaard’s relevant work[1] – relies on the fact that constitutive norms seem to be less mysterious than not-clearly-constitutive norms. There arguably is nothing mysterious about, say, the norms of certain reasonably-well-defined activities, like building a house, or playing chess. And challenges by the relevant skeptic – the one asking "Why should I make sure the house I’m building can shelter people from the weather?" or "Why should I not castle when my king is checked?" – seem very rare, barely intelligible, and anyway remarkably easy to cope with. We should explain to the misguided skeptic that if he doesn’t even try to build something that can protect people from the weather, he’s not in the business of building a house at all; that if she doesn’t even try to play by the rules of chess, she’s not in the business of playing chess at all; and so on. It would be nice, the constitutivist hope seems to go, if we had something equally powerful by way of a response to the skeptic asking "Why be moral?". The other main motivation for constitutivism – most clearly present in David Velleman’s relevant work[2] – starts from a commitment to some rather strong kind of existence-internalism about reasons: An agent has a reason to?, according to such views ), only if she can come to?, or at least to be motivated to?, by sound deliberation starting from her actual motivational set. (shrink)

Kantian constructivists accord a constitutive, justificatory role to the issue of scope: they typically claim that first-order practical thought depends for its authority on being suitably acceptable within the right scope, or by all relevant others, and some Kantian constructivists, notably Onora O'Neill, hold that our views of the nature and criteria of practical reasoning also depend for their authority on being suitably acceptable within the right scope. The paper considers whether O'Neill-type Kantian constructivism can coherently accord this key role (...) to the issue of scope while adhering to the universalist, ‘cosmopolitan’ commitments at its core. The paper argues that this is not so. On the one hand, it shows that O'Neill's attempt to ‘fix’ the scope of practical reasoning supposes, rather than establishes, a view of ethical standing and the scope of practical reasoning. On the other hand, the paper argues that Kantian constructivism should endorse a non-constructivist, perfectionist view of the good to determine that scope. The paper thereby supports the perfectionist conjecture that Kantian constructivism, in order to defend its universalist commitments, should take refuge in non-constructivist, perfectionist considerations, and that Kantian constructivism should therefore construe perfectionism as a partial, though uneasy, ally. (shrink)

John Mackie's stimulating book is a complete and clear treatise on moral theory. His writings on normative ethics-the moral principles he recommends-offer a fresh approach on a much neglected subject, and the work as a whole is undoubtedly a major contribution to modern philosophy.The author deals first with the status of ethics, arguing that there are not objective values, that morality cannot be discovered but must be made. He examines next the content of ethics, seeing morality as a functional device, (...) basically the same at all times but changing significantly in response to changes in the human condition. He sketches a practical moral system, criticizing but also borrowing from both utilitarian and absolutist views. Thirdly, the frontiers of ethics, areas of contact with psychology, metaphysics, theology, law and politcs, are explored.Throughout, his aim is to discuss a wide range of questions that are both philosophical and practical, working within a distinctive version of subjectivism-an "error" theory of the apparent objectivity of values. John Mackie has drawn on the contributions of such classic thinkers as Plato, Aristotle, Hobbes, Hume, Kant and Sidgwick, and on more recent discussions, to produce a thought-provoking account that will inspire both the general reader and the student of philosophy. (shrink)

Introduction -- Part I: Willing as practical knowing -- The will and practical judgment -- Fundamental practical judgments : the wish for happiness -- Part II: From presuppositions of judgment to the idea of a categorical imperative -- The formal presuppositions of practical judgment -- Constraints on willing -- Part III: Interpretation -- The categorical imperative -- Applications -- Conclusion.

Making room for character -- Pluralism and the community of moral judgment -- A cosmopolitan kingdom of ends --Responsibility and moral competence --Can virtue be taught?: the problem of new moral facts -- Training to autonomy: Kant and the question of moral education -- Bootstrapping -- Rethinking Kant's hedonism -- The scope of moral requirement -- The will and its objects -- Obligatory ends -- Moral improvisation -- Contingency in obligation.

This book brings together the lectures that inspired a generation of students--and a regeneration of moral philosophy.

Some of these essays articulate views of justice and liberalism distinct from those found in the two books.

What is the Moral Problem? NORMATIVE ETHICS VS. META-ETHICS It is a common fact of everyday life that we appraise each others' behaviour and attitudes from ...

This volume collects some influential essays in which Simon Blackburn, one of our leading philosophers, explores one of the most profound and fertile of philosophical problems: the way in which our judgments relate to the world. This debate has centered on realism, or the view that what we say is validated by the way things stand in the world, and a variety of oppositions to it. Prominent among the latter are expressive and projective theories, but also a relaxed pluralism that (...) discourages the view that there are substantial issues at stake. The figure of the "quasi-realist" dramatizes the difficulty of conducting these debates. Typically philosophers thinking of themselves as realists will believe that they alone can give a proper or literal account of some of our attachments--to truth, to facts, to the independent world, to knowledge and certainty. The quasi-realist challenge, developed by Blackburn in this volume, is that we can have those attachments without any metaphysic that deserves to be called realism, so that the metaphysical picture that goes with our practices is quite idle. The cases treated here include the theories of value and knowledge, modality, probability, causation, intentionality and rule-following, and explanation. A substantial new introduction has been added, drawing together some of the central themes. The essays articulate a fresh alternative to a primitive realist/anti-realist opposition, and their cumulative effect is to yield a new appreciation of the delicacy of the debate in these central areas. (shrink)

Two centuries after they were published, Kant's ethical writings are as much admired and imitated as they have ever been, yet serious and long-standing accusations of internal incoherence remain unresolved. Onora O'Neill traces the alleged incoherences to attempts to assimilate Kant's ethical writings to modern conceptions of rationality, action and rights. When the temptation to assimilate is resisted, a strikingly different and more cohesive account of reason and morality emerges. Kant offers a "constructivist" vindication of reason and a moral vision (...) in which obligations are prior to rights and in which justice and virtue are linked. O'Neill begins by reconsidering Kant's conceptions of philosophical method, reason, freedom, autonomy and action. She then moves on to the more familiar terrain of interpretation of the Categorical Imperative, while in the last section she emphasizes differences between Kant's ethics and recent "Kantian" ethics, including the work of John Rawls and other contemporary liberal political philosophers. (shrink)

Introduction The Many Moral Realisms Geoffrey Sayre-McCord I. Introduction Recognizing the startling resurgence in realism, ...

The Queen's College, Oxford, UK In his article `Facts and Principles', G.A. Cohen attempts to refute constructivist approaches to justification by showing that, contrary to what their proponents claim, fundamental normative principles are fact- in sensitive. We argue that Cohen's `fact-insensitivity thesis' does not provide a successful refutation of constructivism because it pertains to an area of meta-ethics which differs from the one tackled by constructivists. While Cohen's thesis concerns the logical structure of normative principles, constructivists ask how normative principles (...) should be justified . In particular, their claim that justified fundamental normative principles are fact-sensitive follows from a commitment to agnosticism about the existence of objective moral facts. We therefore conclude that, in order to refute constructivism, Cohen would have to address questions of justification, and take a stand on those long-standing meta-ethical debates about the ontological status of moral notions (for example, realism versus anti-realism) with respect to which he himself wants to remain agnostic. Key Words: John Rawls • normative justification • realism versus anti-realism • methodological versus substantive principles. (shrink)

The publicity of a moral conception is a central idea in Kantian and contractarian moral theory. Publicity carries the idea of general acceptability of principles through to social relations. Without publicity of its moral principles, the intuitive attractiveness of the contractarian ideal seems diminished. For it means that moral principles cannot serve as principles of practical reasoning and justification among free and equal persons. This article discusses the role of the publicity assumption in Rawls’s and Scanlon’s contractualism. I contend that (...) a regard for publicity and a moral conception’s potential to provide a public basis for justification and agreement account for much of the evolution of Rawls’s account of justice after A Theory of Justice . I also discuss whether contractualism can provide a basis for justification and general agreement under the social conditions that it endorses. I contend that it cannot, and conclude with a discussion showing why this should not be a problem for contractualism. Despite appearances, contractualism is a distinctive form of contractarianism, substantially different from Rawls’s position and the social contract tradition out of which it evolved. Key Words: contractarianism • contractualism • John Rawls • public justification • T.M. Scanlon • justice. (shrink)

Constructivism about practical judgments, as I understand it, is the notion that our true normative judgments represent a normative reality, while denying that that reality is independent of our exer-cise of moral and practical judgment. The Kantian strain of practical constructivism (through Kant himself, John Rawls, Christine Korsgaard, and others) has been so influential that it is tempting to identify the constructivist approach in practical domains with the Kantian development of the out-look. In this essay I explore a somewhat different (...) variety of practical constructivism, which I call Aristotelian Constructivism. My aim is to establish conceptual space for this form of constructivism by indicating both in what ways it agrees with its Kantian counterparts and in what ways it differs. I argue that Aristotelian Constructivism is on one sense more faithful to the constructivist enterprise than the Kantian varieties, in that its understanding of both the establishment of practical truth and the vindication of the theory itself is constructivist. (shrink)

The paper addresses O'Neill's view that her version of Kant's Categorical Imperative, namely, the requirement of followability (RF), marks the supreme principle of reason; it takes issue with her claim that RF commits us to Kantian constructivism in practical philosophy. The paper distinguishes between two readings of RF: on a weak reading, RF ranges over all (practical) reasoning but does not commit to constructivism, and on a strong version RF commits to constructivism but fails to meet its own test, and (...) so is self-defeating. The paper argues that RF, if understood strongly, depends for its reasonableness on reasons that cannot coherently be required to meet RF, so that RF cannot be the supreme principle of reason. The paper considers several responses to this problem in order to suggest that RF depends for its reasonableness on perfectionist considerations. (shrink)