Logos deals with several aspects, which are concerned with the content, structure, and argumentation of a speech. It conceives language mainly on the content level, diminishing style and expressive qualities. Most important is the relationship of facts presented in the speech with reality. Thus, the questions of truthfulness and correspondence of reality are a part of logos. Facts, reality, and truthfulness are indecisive and relative terms.
Logos is the appeal towards logical reason, thus the speaker wants to present an argument that appears to be sound to the audience. Aristotle stated that an argument should prove something or at least it should appear to prove something. The ability to achieve logos is to express arguments in the appropriate form for the given communication method and audience. Thus, there is a difference between logical reasoning and rhetorical reasoning.
Aristotle distinguished between scientific and rhetorical proof. The latter needs to build mainly upon the disposition of the audience, whereas in a scientific proof premises are stated explicitly. Thus, a speaker has to adapt his rhetoric proofs towards the knowledge of the audience. Therefore the main goal is not connecting facts given in the speech towards reality, but the relationship of facts given in the speech towards the reality of the audience.
The Goal – A Rhetorical Logical Appeal
The speaker wants to prove the correctness of his argument or at least to make it appear to be sound. A speech is bound to certain limits that inhibit the possibilities of the speaker in his expression, but also the audience in its perception. Thus, the speaker usually can not fully exhibit his expert knowledge, whereas the audience is limited in its perception capabilities and is not able to stop or pause in order to think about the information, thus limiting activities such as memorizing and critical thinking. Thus, to achieve a rhetorical logical appeal can be quite different than a logical appeal of a written argument.
The Ability – Verbal Reasoning
The main dimension of the information, argumentation, and structure is a verbal one, thus the speaker has to express these categories as simply, clearly, and explicitly as possible that the audience can follow his reasoning.
The possibilities of the audience to grasp the argument are limited, hence the speaker must communicate in an understandable way. Additionally, the possibilities of the audience to critically analyze the argument is also limited, thus the ability to create an argument that appears sound is sufficient because rhetoric deals foremost with functionality not with correctness.
Structure of the Speech
The structure of a speech supports the listener in understanding and enjoying the content of the speech. A clear and understandable structure allows the listener to better memorize and process the information given. The speaker needs to structure his speech in such a way that the focus of the speech is preserved.
An argumentation is a linguistic act that intends to create a deliberate change of opinion in the audience with the use of logical reasoning. Thus, an argumentation assumes that there is no consent or decision present in the audience.
While the study of logic is part of rhetorical practice, there is a difference between logic in its purest “written” form and logic in a rhetorical argument. Thus, argumentation in rhetoric is neither bound completely by logic nor is is completely free of logic. Joachim Knape noted in “Was ist Rhetorik?” that rhetoric argumentation has to take in account the process of verbal communication, which follows different rules than written texts.