Informal Logic: A Rhetorical Device

Informal Logic: Etymology, Literal and Conceptual Meanings

Etymology of “Informal Logic”

The term “informal logic” has its roots in both Latin and Greek origins. The word “logic” itself is derived from the Greek word “logos,” meaning “reason” or “word.” The prefix “in-” comes from the Latin “in,” denoting negation or absence. Therefore, “informal logic” can be understood etymologically as the study of reasoning or discourse that is not strictly bound by formal rules. The fusion of these linguistic elements encapsulates the essence of a field that explores reasoning processes outside the rigid structures of formal deductive systems.

Literal and Conceptual Meanings:

• Literal Meaning:
  • Informal: Relating to a lack of strict structure or adherence to established rules.
  • Logic: The study of reasoning, arguments, and inferences.
• Conceptual Meaning:
  • Flexibility: The ability to adapt reasoning processes to various contexts without rigid formal constraints.
  • Everyday Reasoning: Emphasizing the application of logical principles to real-life situations, reflecting the dynamic nature of human thought.
  • Pragmatism: Focusing on effective and practical reasoning rather than strictly adhering to formal logical structures.
  • Informal Fallacies: Exploring common errors in reasoning that may not be apparent within formal logical frameworks.

The combination of these literal and conceptual meanings underscores the interdisciplinary and practical nature of informal logic, highlighting its significance in analyzing everyday reasoning and discourse.

Informal Logic: Definition as a Rhetorical Device

Informal logic, as a rhetorical device, involves the use of everyday reasoning, language, and common sense rather than strict formal structures. It seeks to capture the nuances of human thought and communication, acknowledging the inherent flexibility and context-dependent nature of reasoning in various discourses. Through an exploration of informal fallacies and practical applications, it enriches the understanding of argumentation beyond the confines of traditional deductive systems.

Informal Logic: Types and Examples

Type of Informal Logic	Description	Example
Ad Hominem	Attacks the person rather than the argument	“You can’t trust his opinion; he’s always late.”
Strawman	Misrepresents or distorts the opponent’s argument	“Opponent argues for stricter gun control, and you say they want to ban all guns.”
Circular Reasoning	Uses the conclusion to support the premise	“The Bible is true because it says God wrote it.”
Appeal to Authority	Relies on the opinion of an authority figure as evidence	“Dr. Smith says climate change is a hoax, so it must be.”
Hasty Generalization	Draws a conclusion from insufficient evidence	“I met two rude people from that city; everyone there must be rude.”
False Analogy	Assumes that because two things are alike in some ways, they are alike in other ways	“Choosing a president is like picking a flavor of ice cream.”
Appeal to Ignorance	Argues that a claim is true because it has not been proven false, or vice versa	“There’s no evidence that aliens don’t exist, so they must exist.”
Red Herring	Introduces irrelevant information to divert attention from the main topic	“Let’s not talk about my failed policies; look at my opponent’s personal life instead.”

This table provides a brief overview of some common types of informal logic along with concise descriptions and examples to illustrate each type.

Informal Logic: Examples in Everyday Life

1. Ad Hominem:
   • Example: Dismissing a political argument based on the appearance or personal behavior of the speaker rather than addressing the substance of their points.
2. Strawman:
   • Example: Misrepresenting a friend’s suggestion for a weekend plan, making it easier to reject by exaggerating or distorting its details.
3. Circular Reasoning:
   • Example: Asserting that you are a good leader because you have the qualities of effective leadership, without providing any external evidence or support.
4. Appeal to Authority:
   • Example: Accepting a health product as effective solely because a celebrity endorses it, without considering scientific evidence.
5. Hasty Generalization:
   • Example: Concluding that all students from a particular school are academically weak based on the performance of one or two individuals.
6. False Analogy:
   • Example: Comparing learning a new language to riding a bike, assuming the ease of one activity translates to the other.
7. Appeal to Ignorance:
   • Example: Believing in supernatural phenomena because there is no concrete evidence proving their non-existence.
8. Red Herring:
   • Example: Shifting a conversation about environmental conservation to a discussion on the economy to divert attention from the main topic.
9. Slippery Slope:
   • Example: Arguing against a small tax increase, claiming it will lead to a series of events resulting in economic collapse.
10. False Cause:
    • Example: Associating an increase in ice cream sales with a rise in drowning incidents, implying a causal link without proper evidence.

These examples illustrate how informal logic can manifest in various aspects of everyday life, from personal conversations to public discourse, influencing decision-making and argumentation.

Informal Logic in Literature: Suggested Readings

1. Aristotle. Prior Analytics. Translated by Hugh Tredennick, Harvard University Press, 1938.
2. Eco, Umberto. Semiotics and the Philosophy of Language. Indiana University Press, 1986.
3. Quine, W. V. O. Word and Object. MIT Press, 2013.
4. Searle, John R. Speech Acts: An Essay in the Philosophy of Language. Cambridge University Press, 1969.
5. Tarski, Alfred. Logic, Semantics, Metamathematics: Papers from 1923 to 1938. Translated by J. H. Woodger, Hackett Publishing Company, 1983.
6. van Benthem, Johan. A Manual of Intensional Logic. Center for the Study of Language and Information, 1988.
7. Walton, Douglas. Informal Logic: A Pragmatic Approach. Cambridge University Press, 2008.
8. Wittgenstein, Ludwig. Tractatus Logico-Philosophicus. Translated by C. K. Ogden, Routledge & Kegan Paul, 1922.
9. Woods, John. Paradox and Paraconsistency: Conflict Resolution in the Abstract Sciences. Cambridge University Press, 2003.
10. Zalta, Edward N. (Ed.). Stanford Encyclopedia of Philosophy. Stanford University, 2022, https://plato.stanford.edu/.