There are two main objections against epistemological foundation of logical principles: 1. Every argument for them must necessarily make use of them. 2. Logical principles cannot be abstracted from experience because they imply elements of meaning that exceed in principle our finite experience (like universality & necessity). In opposition to these objections I argue for Husserl's thesis that logic needs a theory of experience as a foundation. To show the practicability of his attempt I argue that he is able (...) to avoid the two circles mentioned. Motivated by this investigation the Appendix presents some mathematical doubts concerning the proofs by Cantor of the transfiniteness of the set of real numbers. (shrink)

Take a correct sequent of formal logic, perhaps a simple logical truth, like the law of excluded middle, or something with premises, like disjunctive syllogism, but basically a claim of the form \.Γ can be empty. If you don’t like my examples, feel free to choose your own, everything I have to say should apply to those as well. Such a sequent attributes the properties of logical truth or logical consequence to a schematic sentence or argument. This paper aims (...) to answer the question of how beliefs in such attributions are justified, on both its descriptive and normative interpretations; I aim to say when we generally take ourselves to be justified in forming such beliefs, and to make it plausible that beliefs formed this way really are justified.We can ask such questions about many domains but there are special difficulties for answering them in logic. Some of the difficulties stem from the fact that logic is thought t.. (shrink)

The proof-theoretic analysis of logical semantics undermines the received view of proof theory as being concerned with symbols devoid of meaning, and of model theory as the sole branch of logical theory entitled to access the realm of semantics. The basic tenet of proof-theoretic semantics is that meaning is given by some rules of proofs, in terms of which all logical laws can be justified and the notion of logical consequence explained. In this paper an attempt will be made to (...) unravel some aspects of the issue and to show that this justification as it stands is untenable, for it relies on a formalistic conception of meaning and fails to recognise the fundamental distinction between semantic definitions and rules of inference. It is also briefly suggested that the profound connection between meaning and proofs should be approached by first reconsidering our very notion of proof. (shrink)

In Sect. 1 it is argued that systems of logic are exceptional, but not a priori necessary. Logics are exceptional because they can neither be demonstrated as valid nor be confirmed by observation without entering a circle, and their motivation based on intuition is unreliable. On the other hand, logics do not express a priori necessities of thinking because alternative non-classical logics have been developed. Section 2 reflects the controversies about four major kinds of non-classical logics—multi-valued, intuitionistic, paraconsistent and (...) quantum logics. Its purpose is to show that there is no particular domain or reason that demands the use of a non-classical logic; the particular reasons given for the non-classical logic can also be handled within classical logic. The result of Sect. 2 is substantiated in Sect. 3, where it is shown (referring to other work) that all four kinds of non-classical logics can be translated into classical logic in a meaning-preserving way. Based on this fact a justification of classical logic is developed in Sect. 4 that is based on its representational optimality. It is pointed out that not many but a few non-classical logics can be likewise representationally optimal. However, the situation is not symmetric: classical logic has ceteris paribus advantages as a unifying metalogic, while non-classical logics can have local simplicity advantages. (shrink)

Anti-exceptionalism about logic is the thesis that logic is not special. In this paper, I consider, and reject, a challenge to this thesis. According to this challenge, there are basic logical principles, and part of what makes such principles basic is that they are epistemically exceptional. Thus, according to this challenge, the existence of basic logical principles provides reason to reject anti-exceptionalism about logic. I argue that this challenge fails, and that the exceptionalist positions motivated by it (...) are thus unfounded. I make this case by disambiguating two senses of ‘basic’ and showing that, once this disambiguation is taken into account, the best reason we have for thinking that there are basic principles actually implies that those principles do not require a special epistemology. Consequently, the existence of basic logical principles provides reason to accept, rather than reject, anti-exceptionalism concerning the epistemology of logic. I conclude by explaining how an abductivist, anti-exceptionalist approach to the epistemology of logic can accommodate the notion of basic logical principles. (shrink)

In this paper we consider logical inference as an activity that results in proofs and hence produces knowledge. We suggest to merge the semantical analysis of deliberatively seeing-to-it-that from stit theory and the semantics of the epistemic logic with justification from. The general idea is to understand proving that A as seeing to it that a proof of A is available. We introduce a semantics of various notions of proving as an activity and present a number of valid (...) principles that relate the various notions of proving to each other and to notions of justified knowledge, implicit knowledge, and possibility. We also point out and comment upon certain principles our semantics fails to validate. (shrink)

Joan Weiner has recently claimed that Frege neither uses, nor has any need to use, a truth-predicate in his justification of the logical laws. She argues that because of the assimilation of sentences to proper names in his system, Frege does not need to make use of the Quinean device of semantic ascent in order to formulate the logical laws, and that the predicate ‘is the True’, which is used in Frege's justification, is not to be considered as (...) a truth-predicate, because it does not apply to true sentences or true thoughts. The present paper aims to show that Frege needs to use, and does use, a truth-predicate in this context. It is argued, first, that Frege needs to use a truthpredicate in order to show that the truth of the logical laws is evident from the senses of the sentences by means of which they are formulated, and second, that the predicate that he actually uses, ‘is the True’, must be considered as a truth-predicate in the relevant sense, because it can be used and is actually used by Frege to explain the truth-conditions of thoughts. To defend this interpretation, it is discussed whether the explanatory use of ‘is the True’ in Frege's system is compatible with his deflationary analysis of ‘true’. The paper's conclusion is that there is indeed a conflict here; but, from Frege's point of view, this conflict is due merely to the logical imperfection of natural language and does not affect the proper system but only its propaedeutic. (shrink)

How are justifications for religious violence developed and dothey differ from secular justifications for violence? Can liberalsocieties tolerate potentially violent religious groups? Can thosewho accept religious justifications for violence be dissuaded fromacting violently? Including six in-depth contemporary case studies,The Justification of Religious Violence is the first book toexamine the logical structure of justifications of religiousviolence. The first book specifically devoted to examining the logicalstructure of justifications of religious violence Seeks to understand how justifications for religious violenceare developed and how (...) or if they differ from ordinary secularjustifications of violence Examines 3 widely employed premises used in religiousjustifications of violence – ‘cosmic war’, theimportance of the afterlife, and ‘sacred values’ Considers to what extent liberal democratic societies shouldtolerate who hold that their religion justifies violent acts Reflects on the possibility of effective policy measures topersuade those who believe that violent action is justified byreligion, to refrain from acting violently Informed by recent work in psychology, cognitive science,neuroscience and evolutionary biology Part of the Blackwell Public Philosophy Series. (shrink)

It is often taken for granted by writers who propose--and, for that matter, by writers who oppose--'justifications' of inductions, that deduction either does not need, or can readily be provided with, justification. The purpose of this paper is to argue that, contrary to this common opinion, problems analogous to those which, notoriously, arise in the attempt to justify induction, also arise in the attempt to justify deduction.

Argumentation schemes are forms of argument that capture stereotypical patterns of human reasoning, especially defeasible ones like argument from expert opinion, that have proved troublesome to view deductively or inductively. Much practical work has already been done on argumentation schemes, proving their worth in A1 [19], but more precise investigations are needed to formalize their structures. The problem posed in this paper is what form justification of a given scheme, as having a certain precise structure of inference, should take. (...) It is argued that defeasible argumentation schemes require both a systematic and a pragmatic justification, of a kind that can only be provided by the case study method of collecting key examples of arguments of the types traditionally classified as fallacies, and subjecting them to comparative examination and analysis. By this method, postulated structures for schemes can be formulated as hypotheses to solve three kinds of problems: (1) how to classify such arguments into different types, (2) how to identify their premises and conclusions, and (3) how to formulate the critical questions used to evaluate each type of argument. (shrink)

I want to discuss philosophically, to glance at the logic of, the parts of this expression “the justification of punishment” and then to draw from this discussion one or two morals for discussions of the justification of punishment. This paper is based on one originally given to the Scots Philosophy Club at its Aberdeen meeting in 1953, as the third part of a symposium on The Justification of Punishment.

It is proved that all the isomorphisms in the cartesian category freely generated by a set of objects can be written in terms of arrows from the symmetric monoidal category freely generated by the same set of objects. This proof yields an algorithm for deciding whether an arrow in this free cartesian category is an isomorphism.

The paper examines two of the most influential approaches to the problem of the justification of perceptual knowledge: representationalism and direct realism, taken in a version of epistemological disjunctivism. The problem itself can be represented as the need to demonstrate that there is a logical connection between a statement about the perception of a certain fact, p, and a statement about the knowledge of p. The article notes that both approaches face the problem of “the silence of the senses.” (...) This problem was pointed out by Ch.Travis, who tried to show that the content of sensory experience is not propositional; senses themselves do not tell us what fact we are dealing with when perceptually interacting with the world. The first part of the article reconstructs the argument from looks that Travis proposed to criticize representationalism. This part demonstrates that we cannot accept representationalism as an approach in the philosophy of perception that successfully overcomes the shortcomings of sense data theory. The main drawback of this theory was its adherence to the myth of the given—the idea that in perceptual experience we are dealing with non-propositional, non-conceptual “raw” data. The second part of the paper notes that Travis’s argument can also be directed against such a version of direct realism as epistemological disjunctivism, since according to representatives of this theory, the content of veridical perceptual experience, being identical with the perceived state of affairs, is propositional. This part also analyzes the response to Travis from such a representative of this theory as J.McDowell. While McDowell rejects propositionalism, he nevertheless insists that the content of perceptual experience must be regarded as conceptual. It allows us to avoid the myth of the given. In conclusion, criticism of McDowell’s approach from the phenomenological position taken by H.Dreyfus is discussed, and it is noted that McDowell’s conceptualism is quite compatible with both phenomenology and enactivism. The enactivist understanding of perception that we find in McDowell leads us to accept the enactivist account of perceptual knowledge, where the foundation of knowledge is action, i.e. something epistemically groundless. (shrink)

BackgroundIn many countries health insurers, employers and especially governments are increasingly using pressure and coercion to enhance healthier lifestyles. For example by ever higher taxes on cigarettes and alcoholic beverages, and ever stricter smoke-free policies. Such interventions can enhance healthier behaviour, but when they become too intrusive, an unfree society can emerge. Which lifestyle interventions that use pressure or coercion are justifiable and which are not? We tried to develop an assessment model that can be used for answering this question, (...) on a generally acceptable way, for all sorts of lifestyle interventions.MethodsThe intended assessment model was developed in three phases. In the first phase the model was theoretically developed on the basis of literature study and reasoning. In the second phase the model was empirically tested by assessing two detailed cases from everyday practice using the model. The model was improved again and again. In the third phase the 10th version of the model was developed while writing this article.ResultsAn assessment model for the justification of intrusive lifestyle interventions. It comprises three components: 12 assessment criteria ; an assessment structure with three filters ; a way of assessing.ConclusionsWe have developed an assessment model for the justification of lifestyle interventions that use pressure or coercion to promote health. The correctness, completeness and practicality of the model are likely. Important principles for the justification are the logic and completeness of the underlying argumentation and the proper use of the available scientific information. Parties for and against a particular intervention could use the model to test and strengthen their argumentation and to improve the quality of the intervention. (shrink)

It is argued that existing axiomatic theories of utility do not provide the utility principle or the principle of maximising expected utility with a formal justification. It is also argued that these theories only put mild constraints on a decision-maker in a decision-context. Finally, it is argued that the prospects are not particularly bright for finding formal non-circular arguments for the utility principle that do not rely on the law of large numbers.

Whether empirical givenness has the reliability that foundationalists expect is a point about which some philosophers are highly skeptical. Sellars took the doctrine of givenness as a “myth,” denying the existence of immediate perceptual experience. The arguments in contemporary Western epistemology are concentrated on whether sensory experience has conceptual contents, and whether there is any logical relationship between perceptions and beliefs. In fact, once the elements of words and conceptions in empirical perception are affirmed, the logical relationship between perceptual experience (...) and empirical belief is also affirmed. This relationship takes place through perceptual experience acting as evidence for beliefs. The real problem lies in how one should distinguish between the different relationships with perception of singular beliefs and of universal beliefs, and in how singular beliefs can provide justification for universal beliefs. (shrink)

In the epistemological trajectory of Philosophy of Religion, contemporary religious epistemologists seem to have undertaken the task of attestation of religious beliefs, their defence, ascertainment and justification, resorting to sanctioned methods of epistemic justification. The models of epistemic justification of religious beliefs they have adopted were intended to bring in a kind of objectivity into religious realm and make meaningful assertions on shared experiences. The acclamation of such esteemed epistemic attempts should be viewed as feverish attempts made (...) by religious epistemologists to subject religious beliefs to standard epistemic treatment. In this paper, three contemporary models of justification of religious beliefs by three outstanding religious epistemologists, namely, Alvin Plantinga whose theory of proper basicality and the warrant, the epistemological holism with the application of Lakatosian principle in Philosophy of Science by Nancey Murphy and the cumulative case evidentialism by Richard Swinburne are critically analyzed using the parameters of logical consistency, methodological acumen, norms of belief formation, the role of subjectivity, features of religious language and the hermeneutic dynamics. (shrink)

The thesis of this paper is that we can justify induction deductively relative to one end, and deduction inductively relative to a different end. I will begin by presenting a contemporary variant of Hume ’s argument for the thesis that we cannot justify the principle of induction. Then I will criticize the responses the resulting problem of induction has received by Carnap and Goodman, as well as praise Reichenbach ’s approach. Some of these authors compare induction to deduction. Haack compares (...) deduction to induction, and I will critically discuss her argument for the thesis that we cannot justify the principles of deduction next. In concluding I will defend the thesis that we can justify induction deductively relative to one end, and deduction inductively relative to a different end, and that we can do so in a non-circular way. Along the way I will show how we can understand deductive and inductive logic as normative theories, and I will briefly sketch an argument to the effect that there are only hypothetical, but no categorical imperatives. (shrink)

The problem of psychologism in the philosophy of logic and the different solutions of this problem are considered. Both traditional psychologistic and antipsychologistic solutions are shown to be untenable and the need for a new solution is demonstrated. The original program of metapsychologism is advanced as a solution to the problem of psychologism based on deduction-search theory. Two formalized levels of a logical procedure are distinguished: 1) an object-level at which a notion of inference is formalized; 2) a metalevel (...) at which principles of deduction-search are formalized, and a thesis of metapsychologism according to which metalevel processes are formulated. Metapsychologism lifts usual psychologist considerations one level up in the hierarchy of logical procedure, while a nonpsychologist justification of logical relations is kept at the object-level. The application of the thesis of metapsychologism to different concrete logical procedures is considered. (shrink)

The paper is concerned with the epistemological status of testimony and the question of what may confer justification on true testimonial beliefs and enable us to call such beliefs knowledge. In particular, it addresses certain anti-reductionist arguments in the epistemology of testimony and their incompatibility with the grammatical categories of egophoricity (conjunct/disjunct marking) and evidentiality (information source marking) present in the architecture of natural languages. First, the tradition of epistemological individualism and its rationale are discussed, as well as certain (...) attempts within this tradition to include testimony-based beliefs in the body of legitimate and rational beliefs. The next section is concerned with the anti-reductionist approach to testimonial beliefs and some arguments supporting ‘the credulity principle’ grounded in Thomas Reid's philosophy of common sense. The last two sections show how the anti-reductionist argumentation is threatened with an insoluble dilemma when considered in the context of languages with the grammatical categories of egophoricity (conjunct/disjunct marking) and evidentiality (information source marking). Special attention is paid to the justificatory role of egophoric and evidential marking; how these grammatical categories may influence the process of belief formation, and consequently, how this bears upon the nature of justification for testimonial beliefs. The final conclusion of the paper is that the anti-reductionist claim concerning the directness and non-inferential nature of testimonial knowledge is bound to meet objections grounded in the structure of many natural languages. This leads to a paradox: in discussion with reductionism, anti-reductionists do seek support for their arguments in common sense beliefs reflected in everyday language, and, on the other hand, their claims are incompatible with the linguistic data found in a number of natural languages. (shrink)

Jin Yuelin (1895?1984), a Chinese logician and philosopher, is greatly influenced by Hume's and Russell's philosophies. How should we respond to Hume's problem of induction? This is an important clue to understand Jin's whole philosophical career. The first section of this paper gives a brief historical review of Russell and Jin. The second section outlines Hume's skeptical arguments against causality and induction. The third section expounds Russell's justification of induction by discussing his views on Hume's skepticism, causality, principle of (...) induction, and empirical postulates. The fourth section clarifies Jin's justification of induction by discussing his critique of Hume's epistemology and his arguments for the reliability of causality and the eternal truth and apriority of the principle of induction. The final section compares Jin's justification of induction with Russell's and concludes that there are similarities and differences between their projects and that both their attempts fail. This paper takes the similar responses to the problem of induction by Jin and Russell to demonstrate the communication that there has been between Chinese philosophers and the Western ones. (shrink)

It is with these words that Alan Gewirth opened his 1972 Lindley Lecture at the University of Kansas. And he immediately followed up his opening words with a more or less blanket indictment of almost the entire group of contemporary writers on meta-ethics, who, he would aver, while claiming to be "rationalists" in the matter of the rational justification of moral principles, and while making much of how far they have distanced themselves from the old-line emotivists in this very (...) regard, have nevertheless just not brought it off, so far as their own provision for any such rational justification is concerned. Thus while the emotivists had tended to hold that such reasons as a person might give in support of moral principles could not really function as reasons, but only as causes that might impel or compel acceptance of such principles, the latter-day "rationalists," as Gewirth calls them, insist that good reasons are always in order and logically relevant, so far as any moral or even evaluative judgment is concerned. Indeed, merely to call a thing good, or to judge an action right or wrong, already implies that such a judgment is put forward as one that is universalizable and for which good reasons can be given. Unfortunately, however,—Gewirth goes on to insist—reasons and justifications of this sort turn out, even on the admission of the rationalists themselves, to be valid only on the prior assumption of what might be called "the moral point of view.". (shrink)

The phenomenological movement begins in the Prolegomena to Husserl’s Logical Investigations as a philosophy of logic. Despite this, remarkably little attention has been paid to Husserl’s arguments in the Prolegomena in the contemporary philosophy of logic. In particular, the literature spawned by Gilbert Harman’s work on the normative status of logic is almost silent on Husserl’s contribution to this topic. I begin by raising a worry for Husserl’s conception of ‘pure logic’ similar to Harman’s challenge to (...) explain the connection between logic and reasoning. If logic is the study of the forms of all possible theories, it will include the study of many logical consequence relations; by what criteria, then, should we select one consequence relation as correct? I consider how Husserl might respond to this worry by looking to his late account of the ‘genealogy of logic’ in connection with Gurwitsch’s claim that ‘[i]t is to prepredicative perceptual experience … that one must return for a radical clarification and for the definitive justification of logic’. Drawing also on Sartre and Heidegger, I consider how prepredicative experience might constrain or guide our selection of a logical consequence relation and our understanding of connectives like implication and negation. (shrink)

Many philosophers have claimed that Bayesianism can provide a simple justification for hypothetico-deductive inference, long regarded as a cornerstone of the scientific method. Following up a remark of van Fraassen, we analyze a problem for the putative Bayesian justification of H-D inference in the case where what we learn from observation is logically stronger than what our theory implies. Firstly, we demonstrate that in such cases the simple Bayesian justification does not necessarily apply. Secondly, we identify a (...) set of sufficient conditions for the mismatch in logical strength to be justifiably ignored as a "harmless idealization''. Thirdly, we argue, based upon scientific examples, that the pattern of H-D inference of which there is a ready Bayesian justification is only rarely the pattern that one actually finds at work in science. Whatever the other virtues of Bayesianism, the idea that it yields a simple justification of a pervasive pattern of scientific inference appears to have been oversold. (shrink)

In the present paper we propose a system of propositional logic for reasoning about justification, truthmaking, and the connection between justifiers and truthmakers. The logic of justification and truthmaking is developed according to the fundamental ideas introduced by Artemov. Justifiers and truthmakers are treated in a similar way, exploiting the intuition that justifiers provide epistemic grounds for propositions to be considered true, while truthmakers provide ontological grounds for propositions to be true. This system of logic (...) is then applied both for interpreting the notorious definition of knowledge as justified true belief and for advancing a new solution to Gettier counterexamples to this standard definition. (shrink)

The account of meta-induction (G. Schurz, Hume’s problem solved: the optimality of meta-induction, MIT Press, Cambridge, 2019) proposes a two-step solution to the problem of induction. Step 1 consists in a mathematical a priori justification of the predictive optimality of meta-induction, upon which step 2 builds a meta-inductive a posteriori justification of object-induction based on its superior track record (Sect. 1). Sterkenburg (Br J Philos Sci, forthcoming. 10.1086/717068/) challenged this account by arguing that meta-induction can only provide a (...) (non-circular) justification of inductive predictions for now and for the next future, but not a justification of inductive generalizations (Sect. 2). This paper develops a meta-inductive method that does provide an a posteriori justification of inductive generalizations, in the form of exchangeability conditions (Sect. 3). In Sect. 4, a limitation of the proposed method is worked out: while the method can justify weakly lawlike generalizations, the justification of strongly lawlike generalizations (claimed to hold for all eternity) requires epistemic principles going beyond meta-induction based on predictive success. (shrink)

The results of an empirical study of 150 justifications of verdicts of the Polish Constitutional Tribunal are discussed. CT justifies its decisions mostly on authoritative references to previous decisions and other doxa- type arguments. It thus does not convince the audience of a decision's validity, but rather documents it. Further, the methodology changes depending on features of the case. The results are analysed using a conceptual framework of sociological systems theory. It is shown that CT's justification methodology ignores the (...) redundancy of the legal system, finding redundancy redundant. This is a risky strategy of decision- making, enabling political influence. (shrink)

A notion of experimental series is developed, in which experiments or experimental sets are connected through experimental suggestions arising from previous experimental outcomes. To that end, the justification of Howard Temin’s DNA provirus hypothesis is examined. The hypothesis originated with evidence from two exploratory experimental sets on an oncogenic virus and was substantiated by including evidence from three additional experimental sets. Collectively these sets comprise an experimental series and the accumulative evidence from the series was adequate to justify the (...) hypothesis by persuading the virology community of its veracity. The notion of crucial experiment is also discussed in terms of experimental series. (shrink)

A notion of experimental series is developed, in which experiments or experimental sets are connected through experimental suggestions arising from previous experimental outcomes. To that end, the justification of Howard Temin's DNA provirus hypothesis is examined. The hypothesis originated with evidence from two exploratory experimental sets on an oncogenic virus and was substantiated by including evidence from three additional experimental sets. Collectively these sets comprise an experimental series and the accumulative evidence from the series was adequate to justify the (...) hypothesis by persuading the virology community of its veracity. The notion of crucial experiment is also discussed in terms of experimental series. (shrink)

Theories of epistemic justification are commonly assessed by exploring their predictions about particular hypothetical cases – predictions as to whether justification is present or absent in this or that case. With a few exceptions, it is much less common for theories of epistemic justification to be assessed by exploring their predictions about logical principles. The exceptions are a handful of ‘closure’ principles, which have received a lot of attention, and which certain theories of justification are well (...) known to invalidate. But these closure principles are only a small sample of the logical principles that we might consider. In this paper, I will outline four further logical principles that plausibly hold for justification and two which plausibly do not. While my primary aim is just to put these principles forward, I will use them to evaluate some different approaches to justification and (tentatively) conclude that a ‘normic’ theory of justification best captures its logic. (shrink)

Different analyses of two-wrongs reasoning are presented and provide relief for the Groarke, Tindale, and Fisher analysis which is suggestive of the origin of this type of reasoning in Bentham and Mill. Aquinas's doctrine of double effect is entertained as a possible counterexample (which it is not). Two-wrongs reasoning can be either acceptable (reasonable) or unacceptable, and there are conditions that can be laid down for both situations in discourse. A negative version of the utilitarian principle assists us in understanding (...) two-wrongs reasoning in moral contexts. (shrink)

The paper relates evidence and justification logics, both philosophically and technically. On the philosophical side, it is suggested that the difference between the approaches to evidence in the two families of logics can be explained as a result of their focusing on two different notions of support provided by evidence. On the technical side, a justification logic with operators pertaining to both kinds of support is shown to be sound and complete with respect to a special class (...) of awareness models. In addition, a realization theorem with respect to K is shown to hold for the logic. (shrink)

The author discusses a question related to a certain aspect of justification of legal decisions, often so-called internal justification-a legal decision is internally justified if and only if it can be deduced from the norm(s) applicable to the case, and from the statement(s) describing the facts of the case. According to this notion, infinite irrelevant logical consequences are justified. To avoid this counterintuitive conclusion, the author analyzes three notions of relevance: Sperber-Wilson's notion, Anderson-Belnap's notion, and Schurz's notion. The (...) author presents a reconstruction of the notion of relevance very close to Schurz's notion, extended to make it suitable to the particular characteristics of deontic logic. Finally, this notion of relevance is used to discuss some aspects of the concept of normative system, conceived as a deductive system, that is, a system containing all its logical consequences. (shrink)

ABSTRACT:In this address, I distinguish and explore three conceptions of wages. A wage is a reward, given in recognition of the performance of a valued task. It is also an incentive: a way to entice workers to take and keep jobs, and to motivate them to work hard. Finally, a wage is a price of labor, and like all prices, conveys valuable information about relative scarcity. I show that each conception of wages has its own normative logic, or appropriate (...) justification, and these logics can come apart. This explains some of the debate about wages and makes the project of justifying a wagesimpliciterdifficult. I identify which logic we should choose, since we must choose, and say what this means for how we should think about the justification of pay. (shrink)

Justification of theorems plays a vital role in any rational human activity. It is indispensable in science. The deductive method of justifying theorems is used in all sciences and it is the only method of justifying theorems in deductive disciplines. It is based on the notion of proof, thus it is a method of proving theorems. In the Warsaw School of Logic (WSL) – the famous branch of the Lvov-Warsaw School (LWS) – two types of the method: axiomatic (...) deduction method and natural deduction method were developed and practiced. In this paper, both of these methods are briefly discussed with an emphasis on their historical, groundbreaking significance for logic. The axiomatic method by means of rejection (proposed by Jan Łukasiewicz – a co-creator of the WSL), which is the method of the so-called rejection proof (rejection/refutation method) in logical systems and the proving method of generalized natural deduction, which is a hybrid deduction–refutation method of proving theorems, are also outlined in the paper. The author discusses their historical significance. This paper also contains a brief mention of the most significant results which the application of the discussed methods introduced into contemporary scientific research, not only logical one. (shrink)

Without directly addressing the Demarcation Problem for logic—the problem of distinguishing logical vocabulary from others—we focus on distinctive aspects of logical vocabulary in pursuit of a second goal in the philosophy of logic, namely, proposing criteria for the justification of logical rules. Our preferred approach has three components. Two of these are effectively Belnap’s, but with a twist. We agree with Belnap’s response to Prior’s challenge to inferentialist characterisations of the meanings of logical constants. Belnap argued that (...) for a logical constant to exist, its rules must be conservative over a previously given consequence relation and guarantee the uniqueness of the constant. The twist is that we require logical vocabulary to be provably conservative, not over a previously given formal consequence relation, but over a previously given meaningful vocabulary of a language. Uniqueness is also a feature defined in terms of provability: if two syntactically distinguished expressions are governed by the same rules, then formulas with them as main operators are interderivable. Belnap’s criteria are not only those for the existence of a logical constant, but more: they are what distinguishes logical vocabulary from all other expressions. It is the defining mark of a logical constant that it is provably conservative over the fragment of the language which excludes it and that its rules guarantee its uniqueness. The third component is the topic neutrality of logic. The provable conservativeness of logic over a previously given vocabulary of a language is motivated, in part, by appeal to molecularism in the theory of meaning. Molecularity is a feature endorsed by the theory of meaning as a whole, so it does not distinguish logical constants from other expressions. The same is true for conservativeness. We argue that molecularity, and hence conservativeness, are implicit presuppositions of speakers’ use of language: the addition of new vocabulary to a language is presupposed to be conservative. But this presupposition is one that we should be able reflectively to endorse (such as when attempting a rational reconstruction of the use of the vocabulary). Thus, where conservativeness is found to fail, this defect should be remedied and the use of the vocabulary corrected (as in classical negation) or excised altogether (as in pejoratives). We go on to characterise a notion of topic neutrality, which we argue applies to logical vocabulary. We then note that reflective endorsement of the conservativeness of a topic neutral vocabulary requires a proof that the vocabulary is conservative relative to any base vocabulary. Thus we require that logical vocabulary be demonstrably conservative. Allying this requirement, distinctive of logic, to a general consideration about the commitments of assertion yields a mode of justification for logical constants akin to some conceptions of Harmony, i.e., to the idea that the consequences of assertion of a logical complex need to be warranted by the grounds and ought to be the strongest consequences warranted by the grounds. Intuitionistic logic acquires a somewhat familiar justification but emanating from a new motivation. (shrink)

The article analyses the meta- epistemological problem of the justification of a theory of knowledge. The first section is dedicated to the morphological reconstruction of the problem, the second presents a diagnosis of the problem in terms of a metatheoretical and logically non- contradictory "petitio principii" and the third delineates the limits within which strategies for the treatment of the problem could be elaborated.

In this paper I discuss the problem of rationality of beliefs. The standard model of rationality proposes three conditions: 1) proper articulation, 2) respecting the requirements of logic , 3) sufficient justification. The second condition is usually understood as two requirements: one concerning consistency, the other suitable deductive abilities. This idea of logical rationality is idealised and not used in practice. For this reason the idealized conception should be reformulated. The conception of minimal logical rationality requires the fulfilment (...) of some conditions but it would not presuppose logical omniscience. (shrink)