The phenomenology of a priori intuition is explored at length (where a priori intuition is taken to be not a form of belief but rather a form of seeming, specifically intellectual as opposed to sensory seeming). Various reductive accounts of intuition are criticized, and Humean empiricism (which, unlike radical empiricism, does admit analyticity intuitions as evidence) is shown to be epistemically self-defeating. This paper also recapitulates the defense of the thesis of the Autonomy and Authority of Philosophy given in the (...) author’s “A Priori Knowledge and the Scope of Philosophy” (Philosophical Studies, 1996). (shrink)
This study provides a unified theory of properties, relations, and propositions (PRPs). Two conceptions of PRPs have emerged in the history of philosophy. The author explores both of these traditional conceptions and shows how they can be captured by a single theory.
The paper begins with a clarification of the notions of intuition (and, in particular, modal intuition), modal error, conceivability, metaphysical possibility, and epistemic possibility. It is argued that two-dimensionalism is the wrong framework for modal epistemology and that a certain nonreductionist approach to the theory of concepts and propositions is required instead. Finally, there is an examination of moderate rationalism’s impact on modal arguments in the philosophy of mind -- for example, Yablo’s disembodiment argument and Chalmers’s zombie argument. A less (...) vulnerable style of modal argument is defended, which nevertheless wins the same anti-materialist conclusions sought by these other arguments. (shrink)
The topic of a priori knowledge is approached through the theory of evidence. A shortcoming in traditional formulations of moderate rationalism and moderate empiricism is that they fail to explain why rational intuition and phenomenal experience count as basic sources of evidence. This explanatory gap is filled by modal reliabilism -- the theory that there is a qualified modal tie between basic sources of evidence and the truth. This tie to the truth is then explained by the theory of concept (...) possession: this tie is a consequence of what, by definition, it is to possess (i.e., to understand) one’s concepts. A corollary of the overall account is that the a priori disciplines (logic, mathematics, philosophy) can be largely autonomous from the empirical sciences. (shrink)
This paper provides a defense of two traditional theses: the Autonomy of Philosophy and the Authority of Philosophy. The first step is a defense of the evidential status of intuitions (intellectual seemings). Rival views (such as radical empiricism), which reject the evidential status of intuitions, are shown to be epistemically self-defeating. It is then argued that the only way to explain the evidential status of intuitions is to invoke modal reliabilism. This theory requires that intuitions have a certain qualified modal (...) tie to the truth. This result is then used as the basis of the defense of the Autonomy and Authority theses. The paper closes with a defense of the two theses against a potential threat from scientific essentialism. (shrink)
Radical empiricism is the view that a person's experiences (sensory and introspective), or a person's observations, constitute the person's evidence. This view leads to epistemic self-defeat. There are three arguments, concerning respectively: (1) epistemic starting points; (2) epistemic norms; (3) terms of epistemic appraisal. The source of self-defeat is traced to the fact that empiricism does not count a priori intuition as evidence (where a priori intuition is not a form of belief but rather a form of seeming, specifically intellectual (...) as opposed to sensory). Moderate rationalism, by contrast, avoids self-defeat. (shrink)
Scientific essentialism is the view that some necessities can be known only with the aid of empirical science. The thesis of the paper is that scientific essentialism does not extend to the central questions of philosophy and that these questions can be answered a priori. The argument is that the evidence required for the defense of scientific essentialism is reliable only if the intuitions required by philosophy to answer its central questions is also reliable. Included is an outline of a (...) modal reliabilist theory of basic evidence and a concept-possession account of the reliability of a priori intuition. (shrink)
Recent work in philosophy of language has raised significant problems for the traditional theory of propositions, engendering serious skepticism about its general workability. These problems are, I believe, tied to fundamental misconceptions about how the theory should be developed. The goal of this paper is to show how to develop the traditional theory in a way which solves the problems and puts this skepticism to rest. The problems fall into two groups. The first has to do with reductionism, specifically attempts (...) to reduce propositions to extensional entities-either extensional functions or sets. The second group concerns problems of fine grained content-both traditional 'Cicero'/'Tully' puzzles and recent variations on them which confront scientific essentialism. After characterizing the problems, I outline a non-reductionist approach-the algebraic approach-which avoids the problems associated with reductionism. I then go on to show how the theory can incorporate non-Platonic (as well as Platonic) modes of presentation. When these are implemented nondescriptively, they yield the sort of fine-grained distinctions which have been eluding us. The paper closes by applying the theory to a cluster of remaining puzzles, including a pair of new puzzles facing scientific essentialism. (shrink)
This is a sustained critique of materialism. The contributors offer arguments from conscious experience, rational thought, the interaction of mind and body, and the unity and persisting identity of human persons, and develop a wide range of alternatives.
The paper elaborates upon various points and arguments in the author’s “A Priori Knowledge and the Scope of Philosophy” (Philosophical Studies, 1993), in which the author defends the autonomy of philosophy from the empirical sciences. It provides, for example, an extended defense of the modal reliabilist theory of basic evidence, including a new argument against evolutionary explanations of the reliability of intuitions. It also contains a fuller discussion of how to neutralize the threat of scientific essentialism to the autonomy of (...) philosophy. (shrink)
Functionalism would be mistaken if there existed a system of deviant relations (an “anti-mind”) that had the same functional roles as the standard mental relations. In this paper such a system is constructed, using “Quinean transformations” of the sort associated with Quine’s thesis of the indeterminacy of translation. For example, a mapping m from particularistic propositions (e.g., that there exists a rabbit) to universalistic propositions (that rabbithood is manifested). Using m, a deviant relation thinking* is defined: x thinks* p iff (...) x thinks m(p). Such deviant relations satisfy the commonly discussed functionalist psychological principles. Finally, a more complicated system of deviant relations is constructed, one satisfying sophisticated principles dealing with the self-conscious rational mind. (shrink)
It is argued that, because of scientific essentialism, two currently popular arguments against the mind-body identity thesis -- the multiple-realizability argument and the Nagel-Jackson knowledge argument -- are unsatisfactory as they stand and that their problems are incurable. It is then argued that a refutation of the identity thesis in its full generality can be achieved by weaving together two traditional Cartesian arguments -- the modal argument and the certainty argument. This argument establishes, not just the falsity of the identity (...) thesis, but also the metaphysical possibility of disembodiment. (shrink)
This paper provides a new approach to a family of outstanding logical and semantical puzzles, the most famous being Frege's puzzle. The three main reductionist theories of propositions (the possible-worlds theory, the propositional-function theory, the propositional-complex theory) are shown to be vulnerable to Benacerraf-style problems, difficulties involving modality, and other problems. The nonreductionist algebraic theory avoids these problems and allows us to identify the elusive nondescriptive, non-metalinguistic, necessary propositions responsible for the indicated family of puzzles. The algebraic approach is also (...) used to defend antiexistentialism against existentialist prejudices. The paper closes with a suggestion about how this theory of content might enable us to give purely semantic (as opposed to pragmatic) solutions to the puzzles based on a novel formulation of the principle of compositionality. (shrink)
Presented here is an argument for the existence of universals. Like Church's translation- test argument, the argument turns on considerations from intensional logic. But whereas Church's argument turns on the fine-grained informational content of intensional sentences, this argument turns on the distinctive logical features of 'that'-clauses embedded within modal contexts. And unlike Church's argument, this argument applies against truth-conditions nominalism and also against conceptualism and in re realism. So if the argument is successful, it serves as a defense of full (...) ante rem realism. The argument emphasizes the need for a unified treatment of intensional statements -- modal statements as well as statements of assertion and belief. The larger philosophical moral will be that ante rem universals are uniquely suited to carry a certain kind of modal information. Linguistic entities, mind-dependent universals, and instance-dependent universals are incapable of serving that function. (shrink)
The paper begins with an argument against eliminativism with respect to the propositional attitudes. There follows an argument that concepts are sui generis ante rem entities. A nonreductionist view of concepts and propositions is then sketched. This provides the background for a theory of concept possession, which forms the bulk of the paper. The central idea is that concept possession is to be analyzed in terms of a certain kind of pattern of reliability in one’s intuitions regarding the behavior of (...) the concept. The challenge is to find an analysis that is at once noncircular and fully general. Environmentalism, anti-individualism, holism, analyticity, etc. provide additional hurdles. The paper closes with a discussion of the theory’s implications for the Wittgenstein-Kripke puzzle about rule-following and the Benacerraf problem concerning mathematical knowledge. (shrink)
This is the only complete logic for properties, relations, and propositions (PRPS) that has been formulated to date. First, an intensional abstraction operation is adjoined to first-order quantifier logic, Then, a new algebraic semantic method is developed. The heuristic used is not that of possible worlds but rather that of PRPS taken at face value. Unlike the possible worlds approach to intensional logic, this approach yields a logic for intentional (psychological) matters, as well as modal matters. At the close of (...) the paper, the origin of incompleteness in logic is investigated. The culprit is found to be the predication relation, a relation on properties and relations that is expressed in natural language by the copula. (shrink)
Modal intuitions are the primary source of modal knowledge but also of modal error. According to the theory of modal error in this paper, modal intuitions retain their evidential force in spite of their fallibility, and erroneous modal intuitions are in principle identifiable and eliminable by subjecting our intuitions to a priori dialectic. After an inventory of standard sources of modal error, two further sources are examined in detail. The first source - namely, the failure to distinguish between metaphysical possibility (...) and various kinds of epistemic possibility - turns out to be comparatively easy to untangle and poses little threat to intuition-driven philosophical investigation. The second source is the local misunderstanding of one's concepts . This pathology may be understood on analogy with a patient who is given a clean bill of health at his annual check-up, despite his having a cold at the time of the check-up: although the patient's health is locally disrupted, his overall health is sufficiently good to enable him to overcome the cold without external intervention. Even when our understanding of certain pivotal concepts has lapsed locally, our larger body of intuitions is sufficiently reliable to allow us, without intervention, to ferret out the modal errors resulting from this lapse of understanding by means of dialectic and/or a process of a priori reflection. This source of modal error, and our capacity to overcome it, has wide-ranging implications for philosophical method - including, in particular, its promise for disarming skepticism about the classical method of intuition-driven investigation itself. Indeed, it is shown that skeptical accounts of modal error are ultimately self-defeating. (shrink)
This paper demonstrates that there is an inconsistency in functionalism in psychology and philosophy of mind. Analogous inconsistencies can be expected in functionalisms in biology and social theory. (edited).
Revised and reprinted; originally in Dov Gabbay & Franz Guenthner (eds.), Handbook of Philosophical Logic, Volume IV. Kluwer 133-251. -- Two sorts of property theory are distinguished, those dealing with intensional contexts property abstracts (infinitive and gerundive phrases) and proposition abstracts (‘that’-clauses) and those dealing with predication (or instantiation) relations. The first is deemed to be epistemologically more primary, for “the argument from intensional logic” is perhaps the best argument for the existence of properties. This argument is presented in the (...) course of discussing generality, quantifying-in, learnability, referential semantics, nominalism, conceptualism, realism, type-freedom, the first-order/higher-order controversy, names, indexicals, descriptions, Mates’ puzzle, and the paradox of analysis. Two first-order intensional logics are then formulated. Finally, fixed-point type-free theories of predication are discussed, especially their relation to the question whether properties may be identified with propositional functions. (shrink)
Revised and reprinted in Handbook of Philosophical Logic, volume 10, Dov Gabbay and Frans Guenthner (eds.), Dordrecht: Kluwer, (2003). -- Two sorts of property theory are distinguished, those dealing with intensional contexts property abstracts (infinitive and gerundive phrases) and proposition abstracts (‘that’-clauses) and those dealing with predication (or instantiation) relations. The first is deemed to be epistemologically more primary, for “the argument from intensional logic” is perhaps the best argument for the existence of properties. This argument is presented in the (...) course of discussing generality, quantifying-in, learnability, referential semantics, nominalism, conceptualism, realism, type-freedom, the first-order/higher-order controversy, names, indexicals, descriptions, Mates’ puzzle, and the paradox of analysis. Two first-order intensional logics are then formulated. Finally, fixed-point type-free theories of predication are discussed, especially their relation to the question whether properties may be identified with propositional functions. (shrink)
Self-consciousness constitutes an insurmountable obstacle to functionalism. Either the standard functional definitions of mental relations wrongly require the contents of self-consciousness to be propositions involving “realizations” rather than mental properties and relations themselves. Or else these definitions are circular. The only way to save functional definitions is to expunge the standard functionalist requirement that mental properties be second-order and to accept that they are first-order. But even the resulting “ideological” functionalism, which aims only at conceptual clarification, fails unless it incorporates (...) the thesis that the mental properties are fully “natural” universals. Accordingly, mental properties are sui generis: first-order, nonphysical, natural universals. (shrink)
In this introduction, before summarizing the contents of the volume, the authors characterize materialism as it is understood within the philosophy of mind, and they identify three respects in which materialism is on the wane.
Direct reference theory faces serious prima facie counterexamples which must be explained away (e.g., that it is possible to know a priori that Hesperus = Phosphorus). This is done by means of various forms of pragmatic explanation. But when those explanations that provisionally succeed are generalized to deal with analogous prima facie counterexamples concerning the identity of propositions, a fatal dilemma results. Either identity must be treated as a four-place relation (contradicting what just about everyone, including direct reference theorists, takes (...) to be essential to identity). Or direct reference theorists must incorporate a view that was rejected in pretty much our first lesson about identity—namely, that Hesperus at twilight is not identical to Hesperus at dawn. One way of the other, the direct reference theory is thus inconsistent with basic principles concerning the logic of identity, which nearly everyone, including direct reference theorists, take as starting points. (shrink)
Arguments are given against the thesis that properties and propositional functions are identical. The first shows that the familiar extensional treatment of propositional functions -- that, for all x, if f(x) = g(x), then f = g -- must be abandoned. Second, given the usual assumptions of propositional-function semantics, various propositional functions (e.g., constant functions) are shown not to be properties. Third, novel examples are given to show that, if properties were identified with propositional functions, crucial fine-grained intensional distinctions would (...) be lost. (shrink)
This paper contains replies to comments on the author's paper "A Priori Knowledge and the Scope of Philosophy." Several points in the argument of that paper are given further clarification: the notion of our standard justificatory procedure, the notion of a basic source of evidence, and the doctrine of modal reliabilism. The reliability of intuition is then defended against Lycan's skepticism and a response is given to Lycan's claim that the scope of a priori knowledge does not include philosophically central (...) topics such as the nature of consciousness. Next a counterfactual account of intuitions proposed by Sosa is criticized. Finally, in response to certain questions raised by Sosa, the explanation of the evidential status of intuition offered in the original paper receives further elaboration. (shrink)
Modal intuitions are not only the primary source of modal knowledge but also the primary source of modal error. An explanation of how modal error arises — and, in particular, how erroneous modal intuitions arise — is an essential part of a comprehensive theory of knowledge and evidence. This chapter begins with a summary of certain preliminaries: the phenomenology of intuitions, their fallibility, the nature of concept-understanding and its relationship to the reliability of intuitions, and so forth. It then identifies (...) two sources of modal error: the first has to do with the failure to distinguish between metaphysical possibility and various kinds of epistemic possibility; the second, with the local misunderstanding of one's concepts. The first source of error is widely misunderstood; the second source has not been discussed in philosophical literature. This source of modal error, and the potential to overcome it, has wide-ranging implications for philosophical method. The failure to understand these sources of modal error has recently led to sceptical accounts of intuition and modal error, which are, ultimately self-defeating. (shrink)
Higher-order theories of properties, relations, and propositions are known to be essentially incomplete relative to their standard notions of validity. It turns out that the first-order theory of PRPs that results when first-order logic is supplemented with a generalized intensional abstraction operation is complete. The construction involves the development of an intensional algebraic semantic method that does not appeal to possible worlds, but rather takes PRPs as primitive entities. This allows for a satisfactory treatment of both the modalities and the (...) propositional attitudes, and it suggests a general strategy for developing a comprehensive treatment of intensional logic. (shrink)
After a brief history of Brentano's thesis of intentionality, it is argued that intentionality presents a serious problem for materialism. First, it is shown that, if no general materialist analysis (or reduction) of intentionality is possible, then intentional phenomena would have in common at least one nonphysical property, namely, their intentionality. A general analysis of intentionality is then suggested. Finally, it is argued that any satisfactory general analysis of intentionality must share with this analysis a feature which entails the existence (...) of a nonphysical "level of organization". (shrink)
Suppose that, for every event, whether mental or physical, there is some physical event causally sufficient for it. Suppose, moreover, that physical reductionism in its various forms fails—that mental properties cannot be reduced to physical properties and mental events cannot be reduced to physical events. In this case, how could there be mental causation? More specifically, how could mental events cause other mental events, physical events, and intentional actions? The primary goal of this paper is to answer this question.
In the history of epistemology, discussions of the a priori have been bound up with discussions of necessity and analyticity, often in confusing ways. Disentangling these confusions is an essential step in the study of the a priori. This will be the aim of my introductory remarks. The goal of the remainder of the paper will then be to try to develop a unified account of the a priori, dealing with the notions of intuition and a priori evidence, the question (...) of why intuitions qualify as evidence, and the question of how they can be a reliable guide to the truth about a priori matters. (shrink)
In a lengthy review article, C. Anthony Anderson criticizes the approach to property theory developed in Quality and Concept (1982). That approach is first-order, type-free, and broadly Russellian. Anderson favors Alonzo Church’s higher-order, type-theoretic, broadly Fregean approach. His worries concern the way in which the theory of intensional entities is developed. It is shown that the worries can be handled within the approach developed in the book but they remain serious obstacles for the Church approach. The discussion focuses on: (1) (...) the fine-grained/coarse-grained distinction, (2) proper names and definite descriptions, (3) the paradox of analysis and Mates’ puzzle, and (4) the logical, semantical, and intentional paradoxes. (shrink)
This paper summarizes and extends the transmodal argument for the existence of universals (developed in full detail in "Universals"). This argument establishes not only the existence of universals, but also that they exist necessarily, thereby confirming the ante rem view against the post rem and in re views (and also anti-existentialism against existentialism). Once summarized, the argument is extended to refute the trope theory of properties and is also shown to succeed even if possibilism is assumed. A nonreductionist theory of (...) universals and properties is then outlined, and it is sketched how to reap the benefits of possibilism and Meinongianism in an actualist setting. (shrink)
It is argued that the distinction between the mental and the nonmental is at bottom logical. The paper begins by sketching and defending a theory of intensional logic in which the notion of logically and metaphysically basic relations (called connections) can be defined. This notion is then employed in an analysis of intentionality: a connection is intentional iff it can contingently connect some individual to some proposition or concept independently of whether it connects the individual to some necessarily equivalent proposition (...) or concept. After potential counterexamples have been explained away, the paper then extends the analysis to a general analysis of mentality. Finally, a "transcendental" argument is given for the thesis that at least some mental relations must be logically and metaphysically basic. (shrink)
Commonplace syntactic constructions in natural language seem to generate ontological commitments to a dazzling array of metaphysical categories - aggregations, sets, ordered n-tuples, possible worlds, intensional entities, ideal objects, species, intensive and extensive quantities, stuffs, situations, states, courses of events, nonexistent objects, intentional and discourse objects, general objects, plural objects, variable objects, arbitrary objects, vague kinds and concepts, fuzzy sets, and so forth. But just because a syntactic construction in some natural language appears to invoke a new category of entity, (...) are we theoreticians epistemically justified in holding that there are such entities? This would hardly seem sufficient. To be epistemically justified, the ontology to which we theoreticians are committed must pass strict standards: the entities must be of the sort required by our best comprehensive theory of the world. The thesis of this paper is that fine-grained type-free intensional entities are like this. If the thesis is right, these entities have a special objective status perhaps not possessed by some of the other ontological categories associated with special syntactic constructions in natural language. In fact, it is plausible to hold that fine-grained type-free intensional entities provide the proper minimal framework for constructing logical and linguistic theories. In this paper my strategy will be to survey the competing conceptions of fine-grained type-free intensionality and to present arguments in support of one of them. Following this narrowing down process, I will go on to the indicated epistemological considerations. (shrink)
This paper answers critical responses to the author’s “A Theory of Concepts and Concept Possession.” The paper begins with a discussion of candidate counterexamples to the proposed analysis of concept possession -- including, e.g., a discussion of its relationship to Frank Jackson’s Mary example. Second, questions concerning the author’s general methodological approach are considered. For instance, it is shown that -- contrary to the critics’ suggestions -- an analysis of concept possession cannot invoke belief alone, but must also invoke intuition. (...) Finally, a defense is given for the realist framework within which the theory of concepts, and of their possession conditions, is formulated. (shrink)
Ontological functionalism's defining tenet is that mental properties can be defined wholly in terms of the general pattern of interaction of ontologically prior realizations. Ideological functionalism's defining tenet is that mental properties can only be defined nonreductively, in terms of the general pattern of their interaction with one another. My Self-consciousness Argument establishes: ontological functionalism is mistaken because its proposed definitions wrongly admit realizations into the contents of self-consciousness; ideological functionalism is the only viable alternative for functionalists. Michael Tooley's critique (...) misses the target: he offers no criticism of - except for an incidental, and incorrect, attack on certain self-intimation principles - and, since he himself proposes a certain form of nonreductive definition, he tacitly accepts. Finally, as with all other nonreductive definitions, Tooley's proposal can be shown to undermine functionalism's ultimate goal: its celebrated materialist solution to the Mind-Body Problem. The explanation of these points will require a discussion of: Frege-Russell disagreements regarding intensional contexts; the relationship between self-consciousness and the traditional doctrine of acquaintance; the role of self-intimation principles in functionalist psychology; and the Kripke-Lewis controversy over the nature of theoretical terms. (shrink)
First, given criteria for identifying universals and particulars, it is shown that stuffs appear to qualify as neither. Second, the standard solutions to the logico-linguistic problem of mass terms are examined and evidence is presented in favor of the view that mass terms are straightforward singular terms and, relatedly, that stuffs indeed belong to a metaphysical category distinct from the categories of universal and particular. Finally, a new theory of the copula is offered: 'The cue is cold', 'The cube is (...) ice', and 'Ice is water' all have the form 'A is B'. On the basis of the logical behavior of stuff-names with respect to this univocal copula, definitions are suggested for 'X is a stuff', 'X composes Y', 'X is a material object', and even 'Matter'. Hence an expanded form of logicism. (shrink)
In this chapter I argue that there is such a barrier created by self-conscious intentional states—conscious intentional states that are about one’s own conscious intentional states. As we will see, however, this result is entirely compatible with a scientific theory of mind, and, in fact, there is an elegant non-reductive framework in which just such a theory may be pursued.
The dominant school of logic, semantics, and the foundation of mathematics construct its theories within the framework of set theory. There are three strategies by means of which a member of this school might attempt to justify his ontology of sets. One strategy is to show that sets are already included in the naturalistic part of our everyday ontology. If they are, then one may assume that whatever justifies the everyday ontology justifies the ontology of sets. Another strategy is to (...) show that set theory is already part of logic. In this case, the ontology of sets would be justified in the sam way logic is justified. The third strategy is to show that set theory plays some unique role in theoretical work. If it does, then its ontology would be justified pragmatically. In this paper it is shown that none of these strategies is successful. One properly constructs foundations, not within set theory. bit within an intensional logic that takes properties, relations, propositions as basic. (shrink)
This paper begins with a brief summary of the Self-consciousness Argument, developed in the author’s paper “Self-consciousness.” (This argument is designed to refute the extant versions of functionalism -- American functionalism, Australian functionalism, and language-of-thought functionalism.) After this summary is given, two thesis are defended. The first is that the Self-consciousness Argument is not guilty of a Fregean equivocation regarding embedded occurrences of mental predicates, as has been suggested by many commentators, including Mark McCullagh. The second thesis is that the (...) Self-consciousness Argument cannot be avoided by weakening the psychological theory upon which Ramsified functional definitions are based. Specifically, it does no good to excise psychological principles involving embedded mental predicates. Why? Because functional definitions based on the resulting sparse theories are exposed to an interesting new family of counterexamples. (shrink)
In this paper, the arguments against the mind-body identity thesis from the author’s  paper, “Mental Properties,” are presented but in significantly more detail. It is shown that, because of scientific essentialism, two currently popular arguments against the identity thesis -- the multiple-realizability argument and the Nagel-Jackson knowledge argument -- are unsatisfactory as they stand and that their problems are incurable. It is then shown that a refutation of the identity thesis in its full generality can be achieved by weaving (...) together two traditional Cartesian arguments -- the modal argument and the certainty argument. This argument establishes, not just the falsity of the identity thesis, but also the metaphysical possibility of disembodiment. The paper ends with a discussion of the nature of the relation between the mind and the body. (shrink)
In the history of philosophy, especially its recent history, a number of definitions of necessity have been ventured. Most people, however, find these definitions either circular or subject to counterexamples. I will show that, given a broadly Fregean conception of properties, necessity does indeed have a noncircular counterexample-free definition.