Analyzing the process of keeping promise we identify its sequence structure and its phase sequences in time. This allows us to arrive at a time order principle forming according to which obligation performance cannot precede in time its sufficient or necessary conditions performance. We further observe that a given promise must always be taken as an element of a certain system of promises. As a result we review definitions of the terms sufficient condition and necessary condition as no more allowing (...) their mutual defining, or symmetry . We try to discover the compliance rules concerning the condition – the conditioned vector, the course of events vector and the time vector. We conclude that it indicates an incorrect use if, provided the condition – the conditioned vector complies with the course of events vector, the negative time difference in the descriptive use of sentences involving either the if-then connective or the only if connective is obtained. Only when using sentences for abductive explanation with a dominating epistemic vector the negative difference of time does not indicate erroneous use; however, this is possible only for the term of sufficient condition. We further suggest reviewed definition generalization involving the terms of sufficient condition and necessary condition containing always a parameter element denot-ing a given modality type, or a particular system of rules, laws, etc. Such definition satisfies Brennan’s requirement of a “general formal scheme” where the notion of sufficient condition and necessary condition symmetry does not apply. (shrink)

The paper proposes a solution to the problem of counterfactuals, building on both Rescher’s epistemic and Tichý’s semantic approaches. The core of the proposed solution is the thesis that when expressing a true counterfactual, the speaker assumes a set of background indicative premises as an implicit parameter. When added tacitly to an unreal antecedent, these premises entail the consequent logically or analytically. We draw a distinction between a potentially unreal and an absolutely unreal condition expressed in the antecedent. We view (...) counterfactuals with a positive time vector and an absolute unreal condition as abbreviated deductive retrodictions. Similarly, we consider counterfactuals with a potentially unreal condition to be abbreviated deductive predictions. In a similar manner, we also explain the truth (falsity) of vacuously true counterpossibles or counterpossible conditionals. In the second part, we discuss the enigmatic backtracking counterfactuals. We propose that their negative time direction is due to their being abductive retrodictions, i.e., explanations of unreal effects based on possible causes in which the conditions remain tacit or unexpressed. The backtracking temporal direction of counterfactual abductive retrodictions is in accordance with the thesis on the positive temporal direction from cause to effect. Thus, we demonstrate that in order to explain backtracking counterfactuals, there is no need to assume violations of laws of nature or a special logic. What we need to do is to take into account the third parameter, i.e., a set of tacit or unexpressed additional propositions, as well as the principle of ceteris paribus as the background. (shrink)

The paper deals with some logical, semantic and methodological aspects of defining and definitions. First of all, basic features of the background semantic theory are specified. Next, three different kinds of definitions are distinguished: codifying definitions, objectual analytic definitions and meaning analytic definitions. It is shown that the relationships between the definiendum and the definiens in a given definition differ with respect to these different kinds of definition. Furthermore, it is argued that definitions and defining are intrinsically connected with so (...) called conceptual systems. Finally, definitions are distinguished from explications. (shrink)

Analyzing the process of keeping promise we identify its sequence structure and its phase sequences in time. This allows us to arrive at a time order principle forming according to which obligation performance cannot precede in time its sufficient or necessary conditions performance. We further observe that a given promise must always be taken as an element of a certain system of promises. As a result we review definitions of the terms sufficient condition and necessary condition as no more allowing (...) their mutual defining, or symmetry (conversion). We try to discover the compliance rules concerning the condition – the conditioned vector, the course of events vector and the time vector. We conclude that it indicates an incorrect use if, provided the condition – the conditioned vector complies with the course of events vector, the negative time difference in the descriptive use of sentences involving either the if-then connective or the only if connective is obtained. Only when using sentences for abductive explanation with a dominating epistemic vector the negative difference of time does not indicate erroneous use; however, this is possible only for the term of sufficient condition. We further suggest reviewed definition generalization involving the terms of sufficient condition and necessary condition containing always a parameter element denoting a given modality type, or a particular system of rules, laws, etc. Such definition satisfies Brennan’s requirement of a “general formal scheme” where the notion of sufficient condition and necessary condition symmetry (conversion) does not apply. (shrink)

The similarity between logic and semantics of the Stoics and Frege has long been known, and it can be explained in various ways. In 2021, Susane Bobzien published a work in which she explains this similarity rather surprisingly: she hypothesizes that Frege generously helped himself with the foundations of Stoic logic as it was published in the first volume of History of Logic in the West by Carl Prantl. However, this hypothesis encounters various problems. The key point of the whole (...) accusation is founded on the formulation of a general propo-sition in language using implication and anaphora, which Frege supposedly took from the Stoics, although in Prantl’s text there is only one example of a sentence with this structure. On the contrary, there are many examples of such sentences in contemporary professional (e.g. legal) texts. Many examples of semantic simi-larities that Bobzien presents are based only on the similarities between isolated concepts; however, that is regularly the case for such concepts with the same conceptual basis. Bobzien presents a significant number of matches only on the basis of results that could allegedly be inferred from the texts. However, this cannot be considered a proof of plagiarism. Bobzien does not consider many sources for the continuity of interpretation such as the so-called hypothetical syllogism found in available textbooks of logic. Last but not least, her claims do not consider many differences between Stoic and Frege’s logic. All this leads us to the conclusion that Bobzien does not present sufficient facts and connections between them that would confirm her hypothesis about Frege’s plagiarism of the Stoic logic: Frege simply was not a plagiarist. (shrink)

It is common opinion that relation between the Aristotelian logic and logic of the Stoic is either complemental or rival. In his analysis, the author criticize claim according to which the Stoic examples of conclusions do not contained universal statements. He is showing that they expressed universal statements standard across implication and by anaphoric connection of pronouns. For this reason it is necessary to revise interpretation of basic, so called unprovable inferring rules of the Stoic. These rules are for predicate (...) logic and their interpretation, as propositional rules, is just special case. On the base of revised rules the author proved through Stoic logical system all valid modes of the first syllogistic figure of Aristotelian categorical syllogism. He also concludes that Aristotelian logic was just fragment of evidently more strong Stoic logic. (shrink)

The expressions sufficient condition and necessary condition are frequently used in various areas in sciences as well as in everyday usage; therefore, they might be taken as expressing well defined notions which should not lead to any serious misunderstandings when used. According to the widely accepted definitions of both concepts, the concept of sufficient condition and that of necessary condition imply their symmetry : if one thing poses a sufficient condition to another thing, the latter is a necessary condition for (...) the former; however, this symmetry is hardly intuitive and it is refused by many scholars. Given the analyses of practical examples and a symmetry concept defence test, one may conclude that this view is unfounded. As a result, the definitions of the two notions are not determined enough and so is the question whether there is just a single pair of the notions or whether there are more of them. (shrink)