The science of logic seeks ways to think correctly and consistently, and essentially covers the basic rules and conditions of reasoning. Since antiquity, when the formations of this purpose were clearly seen along with its various orientations, logic has deviated into two critical paths in the narrow sense of the word. From a general framework, one of these ways was the traditional logic that developed in accordance with the logic of Aristotle while the other one was the new logic (modern, symbolic, logistics logic) that was born as a result of the development of logic based on the symbols and signs of mathematics, such as in algebra and arithmetic. New logic used a formal calculus that was created using some of the symbols and signs of mathematics as opposed to strings of words involving concepts. This symbolic language has a formal form of expression that does not include any content. However, the language of traditional logic is contextual, that is, it depends on the meanings of terms and syntactic elements of the language. Therefore, the new logic expresses its propositions and inferences through a symbolic language in a way that eliminates all these.1 This development, indicating the change in the style of expression ranging from concepts to propositions and inferences, provides the opportunity to go beyond the relationship of traditional logic with concepts and its commitment to the grammatical fiction of language.

Logical positivist thinkers, who analyzed world, thought and language relationship in the context of a linguistic analysis, approached the issues and problems of various disciplines, especially philosophy, in different ways by taking advantage of the opportunities provided by the new logic. Although their ways of approaching the philosophical issues of the 20th century reached a different dimension, perhaps the common main point where they met was the effort to eliminate metaphysics from philosophy. This effort, which took form under the problem of the criterion of meaning, however, showed itself as a key issue simultaneously with the development of the new logic just before the official emergence of logical positivist thought.

In line with the information provided, this article seeks to answer the question of “how the rise of the new logic, which developed differently from traditional logic, affected the approaches of logical positivist thinkers within the framework of the subject of ‘meaning’?” The approaches of Frege, Russell, and Wittgenstein who can be considered as the prominent figures of logical positivist thought have a critical place to answer this question. In this regard, Frege paid attention to the issue of meaning in the distinction between declarative sentences and nouns, and drew a fundamental line between Sinn [sense] and Bedeutung [reference]. Accordingly, a noun can be meaningful even if it does not have a reference object that it can refer to just as in the word “Odysseus” in the following example: “Odysseus was disembarked while sleeping deeply.”2 On the other hand, attention should additionally be paid to the reference in the sentence in the case of declarative sentences since the truth value of the sentence depends on its reference.3 Thus, in order for the statement “Odysseus was disembarked while he was in deep sleep” to receive one of the truth values, the reference of the word “Odysseus” must be taken into account. In this context Frege claimed that there may be sentences that can be assumed to be meaningful even though they lack truth values.

On the other hand, Russell made an important objection to Frege regarding this point, as Russell considered the reference to be equal to the meaning. Therefore, he emphasized that every meaningful sentence must take the value of true or false. One can see Russell’s attitude on this issue especially in his theory of descriptions, where he discusses the possibility of sentences that are able to take truth values without any logical contradiction while at the same time being meaningful despite having no reference. According to Russell, the gains provided by the new logic have a very important role in revealing the essential character of philosophical problems. Just as Whitehead and Russell intended to demonstrate in Principia Mathematica, the symbolic calculus of the new logic offered a new way of approaching the subjects and problems of philosophy.

Wittgenstein tried to establish the foundations of “meaning” within the boundaries of language by taking Russell’s approach further. On one hand, Wittgenstein addressed the issue of “meaning” within the context of his picture theory of language at first; on the other hand, he also analyzed it in the context of truth-function. Since, for him, meaning in language is the expression of a state of affairs through pictures, sentences that belong to metaphysics are meaningless/non-meaningful because these sentences are neither pictures of a state of affairs nor can they be expressed in accordance with logical syntax. The “meaning” issue, which is grounded on the principles of the new logic, has gained a new dimension and a different perspective in the approaches of these thinkers. Under this perspective, the issue of “meaning” became a basic criterion in the attempt to eliminate metaphysical sentences from philosophy, as they are considered meaningless. Therefore, one can say that the approaches of Frege, Russell, and Wittgenstein provided both an origin and a basis for these attempts of the logical positivist thinkers.

Carnap is another logical positivist thinker that will be mentioned within the scope of this study. Similar to Wittgenstein, he approached the issue of the verification of sentences within the framework of the certain verification principles based on the logical syntax of language. Accordingly, Carnap can be said to have drawn a line between meaningful philosophical problems and meaningless pseudo-philosophical problems within the framework of the parallelism between meaning and verification. To Carnap, as a result of linguistic analysis, it can be seen that the pseudo-object-propositions of metaphysics do not refer to objects, but have a structure contrary to logical syntax. However, Ayer analyzed the issue of “meaning” within the context of “verification”, and emphasized that sentences must be verified by a fact (whether an actual one or a possible one) in order for them to be meaningful.4 As for the sentences of metaphysics, these were deemed meaningless because they could neither be verified nor had any possibility of being verified. Consequently, on the way to understanding the attempts to eliminate sentences of metaphysics from philosophy on the grounds that they are not meaningful, that is, they do not have informational value, the first point to consider is perhaps the way “criterion of meaning” is dealt in the new logic.