Wittgenstein and logical necessity

An attempt is made to show that Wittgenstein's later philosophy of logic is not the kind of conventionalism which is often ascribed to him. On the contrary, Wittgenstein gives expression to a “mixed” theory which is not only interesting but tends to resolve the perplexities usually associated with the question of the a priori character of logical truth. I try to show that Wittgenstein is better understood not as denying that there are such things as “logical rules” nor as denying that the results of applying such rules are “logically necessary,” but as trying to understand what it is to appeal to a logical rule and what it means to say that the results of applying such a rule are “necessary.” He is not so much overthrowing standard accounts of logical necessity as discovering the limits of the concept.     

Common sense and psychological theories: The historical nature of logical necessity

The importance of common sense for psychological theories is construed as a limiting condition that must be transcended if a particular psychological theory is expected to have generalizability across cultures and over history. Discussion on the pages of this journal, initiated by Jan Smedslund in 1978, has brought the common-sensical nature of the majority of psychological theories into psychologists' focus of attention. Smedslund has attempted to explicate 'theorems' of common sense that underlie thinking and activities of human beings in a culture—and that are shared by laypersons as well as by psychologists. This article approaches the issue of common sense in psychological theorizing from a developmental perspective. This perspective emphasizes the process of emergence of qualitatively new cognitive phenomena in the course of cultural history. It is argued that the 'logical necessity' based on the 'theorems' of common sense is itself 'historical necessity', as it results from the history of human cultures. Smedslund's 'theorems' of common sense can only be formal, but not substantive, analogues of theorems in geometry, since the latter are ahistorical, whereas the former constitute products of the history of cultures and individuals.     

On the essence of empty properties

This paper deals with generalisations of modally based criteria for determining whether a given property is essential to an individual to the case of generic essences. These criteria usually presuppose extensionally individuated properties. The limitations of their generalisations are demonstrated using the case of the necessarily empty individual property and the necessarily empty individual office. I do not present a novel stance on the discussion of individual essences. The novelty of this paper lies in its claim that none of these criteria can be generalised to generic essences.

     

Soames on the logical empiricists on truth,meaning, convention,and logical truth

Philosophical Studies -     

Essence,necessity, and definition

Philosophical Studies - What is it for something to be essential to an item? For some time, it was standard to think that the concept of necessity alone can provide an answer: for something to be...     

Information-seeking dialogues: Some of their logical properties

The dialogical games introduced in Jaakko Hintikka, Information-Seeking Dialogues: A Model, (Erkenntnis, vol. 14, 1979) are studied here to answer the question as to what the natural logic or the logic of natural language is. In a natural language certain epistemic elements are not explicitly indicated, but they determine which inference rules are valid. By means of dialogical games, the question is answered: all classical first-order rules have to be modified in the same way in which some of them are modified in the transition to intuitionistic logic. (Furthermore, in some cases quantificational rules have to be modified further.) The rules that are left unmodified by intuitionists are applicable only to the output of certain game rules, but not to others. In. this sense, neither classical nor yet intuitionistic logic is the logic of natural language. We need a new type of nonclassical logic, justified by our information-seeking dialogues.     

Modality,invariance, and logical truth

Conclusion Let us sum up. We began with the question, What is the interest of a model-theoretic definition of validity? Model theoretic validity consists in truth under all reinterpretations of non-logical constants. In this paper, we have described for each necessity concept a corresponding modal invariance property. Exemplification of that property by the logical constants of a language leads to an explanation of the necessity, in the corresponding sense, of its valid sentences. I have fixed upon the epistemic modalities in characterizing the logical constants: to be a logical constant in the language of a population is to be invariant over a modality describing complete possible epistemic states of that population (or an idealized analogue thereof). The grounds for this characterization are these: (1) It leads, I believe, to an extensionally reasonable demarcation of the logical constants, including clear cases and excluding clear non-cases. It gives a principled criterion for deciding unclear cases. (2) It provides an analysis of the topic-neutrality of logic. (3) It leads to an explanation of the epistemic necessity of the logical truths in terms of the topic-neutrality of the logical constants.All the same, it is reasonable to ask, even if the suggested demarcation of logic is extensionally correct, whether it can reasonably be expected to be fundamental. The epistemic invariance of an expression is a rather striking property, one which we should want to explain. What is missing, then, is an explanation of the distinguishing epistemic properties of the constants in terms of more fundamental properties involving their understanding and use. It would be these that properly define the nature, not just the extent, of logic.     

Possibility,chance and necessity

Those who deny the usefulness of the concept of “motive” for psychology commonly bring two arguments in support of theirview. The first is that the whole notion of “motive” is “animistic” and “folklorish”, since a motive cannot be directly observed. The second is that “motives” cannot be accurately observed, and therefore are beyond the scope of scientific study, because (a) they are “the secret of the agent”, and (b) the agenthimself has no indubitable knowledge of his “motives”.

In a recent article, Professor MacIver defends the view that the imputation of “motives” is necessary to a complete explanation of behaviour. To the first of the above criticisms, he replies that such a view neglects a part of reality and that since “motives” exist they should be studied by psychology. This reply does nothing to demonstrate the necessity of imputing motives in order to obtain a complete explanation of behaviour. To the second criticism he replies (a) “motives” are not the secret of the agent, and (b) we can only assert that the agent has mistaken his “motive” if we can gain indepen-dent knowledge of it. We can do this, Professor MacIver asserts, by observing typical behaviour in typical circum-stances, and making inferences from the coherence of total situations.

Professor MacIver's replies to the second of the above criticisms are valid only if “motive” is defined as equivalent to “need”, so that we can say “under such-and-such conditions, such-and-such behaviour occurs”. A statement of this type says nothing about the agent's awareness of his goal. When the term “consciousness” is carefully defined along the lines suggested by Boring, the methods of imputation described by Professor MacIver can be seen to lead us only to the agent's “drives”, or “needs”, defined without reference to the agent's awareness of his goal. Professor MacIver uses “motives” to mean “awareness of the goal”, but gives us no clue as to how they may be imputed, and adduces no proof that their imputation is necessary.

A possible criterion of the presence of a “motive” is the degree of direction observable in the organism's varied reac-tions in response to frustration, though the more precise definition of such a criterion must await further experiment.

In view of the ambiguity of the term “motive” and its penumbra of false suggestion, it is desirable that the term be dropped from psychology.