7.3 Logical Reasoning and Argumentation
4 min read•july 31, 2024
Logical reasoning and argumentation are key skills for effective public speaking. They help you build strong, persuasive arguments that can sway your audience. By mastering these techniques, you'll be able to craft compelling speeches that stand up to scrutiny.
Understanding different types of reasoning, like deductive and inductive, is crucial. You'll also need to watch out for common logical fallacies that can weaken your arguments. By combining solid logic with rhetorical appeals, you'll create powerful, convincing presentations.
Principles of Logical Reasoning
Foundations of Logical Reasoning
Top images from around the web for Foundations of Logical Reasoning
.svg.png&w=640&q=75)
Logical reasoning - Wikipedia View original
Is this image relevant?
CRITICAL THINKING STRATEGIES-PPT | OER Commons View original
Is this image relevant?
Critical Thinking Skills | College Success View original
Is this image relevant?
Logical reasoning - Wikipedia View original
Is this image relevant?
CRITICAL THINKING STRATEGIES-PPT | OER Commons View original
Is this image relevant?
1 of 3
Top images from around the web for Foundations of Logical Reasoning
Logical reasoning - Wikipedia View original
Is this image relevant?
CRITICAL THINKING STRATEGIES-PPT | OER Commons View original
Is this image relevant?
Critical Thinking Skills | College Success View original
Is this image relevant?
Logical reasoning - Wikipedia View original
Is this image relevant?
CRITICAL THINKING STRATEGIES-PPT | OER Commons View original
Is this image relevant?
1 of 3
- Logical reasoning employs formal or informal logic to draw conclusions, make inferences, and evaluate arguments based on available and premises
- Structure of an argument consists of premises (supporting statements) and a
- Premises provide justification for the conclusion
- in argumentation refers to the logical connection between premises and conclusion
- requires both validity and true premises
- Critical thinking skills essential for effective logical reasoning
- Analysis
- Evaluation
- Inference
Evidence and Argumentation
- Argumentation constructs and presents arguments to support a or position
- Goals often include persuading others or reaching a conclusion
- Principle of charity interprets an opponent's arguments in their strongest possible form before attempting to refute them
- Various forms of evidence support claims and conclusions
- Empirical data (scientific studies)
- Expert testimony (field specialists)
- Logical proofs (mathematical theorems)
- Analogies (comparisons to similar situations)
Inductive vs Deductive Reasoning
Deductive Reasoning
- Moves from general premises to specific conclusions
- If premises are true, the conclusion must be true
- Syllogism common form of deductive argument
- Major
- Minor premise
- Conclusion
- Example:
- Major premise: All mammals are warm-blooded
- Minor premise: Dogs are mammals
- Conclusion: Therefore, dogs are warm-blooded
Inductive Reasoning
- Draws probable conclusions from specific observations or evidence
- Moves from particular instances to general principles
- Relies on strength of evidence and probability rather than absolute certainty
- Statistical reasoning uses data and probability to draw conclusions about populations or trends
- Example: Survey of 1000 voters shows 60% support for a policy, concluding majority of all voters likely support it
- Principle of sufficient reason states every fact or truth must have an adequate explanation
Constructing Sound Arguments
- Requires careful consideration of premise truth, relevance, and sufficiency in supporting the conclusion
- Balances deductive and inductive approaches based on available evidence and argument goals
- Evaluates strength of premises and logical connections to ensure valid conclusions
Logical Fallacies in Arguments
Personal Attack Fallacies
- attacks the person making an argument rather than addressing the argument itself
- Example: "You can't trust her environmental policy because she drives a gas-guzzling SUV"
- Genetic fallacy dismisses an argument based on its origin rather than its merits
- Example: "That economic theory can't be valid because it was developed by a capitalist"
Misrepresentation Fallacies
- Straw man misrepresents an opponent's argument to make it easier to attack
- Example: "Vegetarians think we should let animals rule the world" (oversimplification of animal rights arguments)
- False dichotomy presents only two options when other alternatives exist
- Example: "Either we cut all social programs or we'll go bankrupt" (ignores middle-ground solutions)
Causal Fallacies
- Post hoc ergo propter hoc assumes one event caused another because it occurred first
- Example: "I wore my lucky socks and we won the game, so my socks must be lucky"
- Hasty generalization draws broad conclusions from insufficient or unrepresentative samples
- Example: "My neighbor is rude, so all people from his country must be rude"
Authority and Popularity Fallacies
- Appeal to authority relies on opinion of an authority figure in an unrelated field
- Example: "This famous actor says climate change isn't real, so it must not be"
- Bandwagon fallacy assumes something is true or good because it's popular
- Example: "Everyone is buying this product, so it must be the best"
Persuasive Argumentation
Rhetorical Appeals
- Classical rhetorical triangle consists of , , and
- Ethos appeals to credibility (speaker's expertise or character)
- Pathos appeals to emotion (audience's feelings or values)
- Logos appeals to logic (facts, statistics, reasoning)
- Emotional appeals engage audience and create connection
- Balance with logical reasoning to maintain credibility
- Vivid language, storytelling, and concrete examples enhance both logical and emotional appeals
- Example: Using a personal anecdote about healthcare costs to support argument for policy change
Audience-Centered Approaches
- Adapt arguments to audience's values, beliefs, and experiences
- Increases relevance and relatability of message
- Anticipate and address potential counterarguments
- Demonstrates comprehensive understanding of issue
- Strengthens overall persuasive power
- Leverage principle of cognitive dissonance
- Highlight inconsistencies between audience's beliefs and actions
- Example: Pointing out disconnect between stated environmental concerns and wasteful habits
Combining Reasoning Strategies
- Employ combination of deductive and
- Tailor to specific context and audience expectations
- Use statistical data to support broader claims (inductive)
- Follow with logical implications of those claims (deductive)
- Structure arguments with clear progression
- Start with agreed-upon premises
- Build towards more contentious conclusions
- Provide multiple lines of evidence to support main points
- Strengthen overall argument resilience
Key Terms to Review (19)
Ad hominem: Ad hominem is a logical fallacy that occurs when an argument is rebutted by attacking the character or motive of the person making the argument, rather than addressing the substance of the argument itself. This tactic distracts from the actual issue at hand and can undermine rational debate, making it crucial to recognize in discussions involving logical reasoning, ethical persuasion, and the balance between persuasion and manipulation.
Analogy: An analogy is a comparison between two different things that highlights some form of similarity between them, often used to clarify or explain an idea. This technique helps audiences relate new information to familiar concepts, making complex ideas more accessible. By drawing parallels, analogies enhance understanding and retention of the message being conveyed.
Argument from authority: An argument from authority is a logical reasoning strategy where the credibility of a claim is supported by citing an authoritative figure or expert in the relevant field. This form of argumentation relies on the idea that if an expert endorses a claim, it is more likely to be true, although it does not guarantee its validity. It plays a significant role in logical reasoning and argumentation by providing a way to bolster arguments with external validation.
Causal argument: A causal argument is a type of reasoning that asserts a cause-and-effect relationship between two or more events or phenomena. This kind of argument often seeks to explain how one event (the cause) leads to another event (the effect), and it can be used to support claims or persuade an audience by establishing a logical connection between variables. Causal arguments rely heavily on evidence and reasoning to demonstrate that a specific cause will lead to a particular outcome.
Claim: A claim is a statement or assertion that something is true or that a particular viewpoint is valid. In logical reasoning and argumentation, claims serve as the foundation for building arguments, providing a basis for supporting evidence and reasoning. By establishing a claim, speakers set the stage for their arguments and engage their audience in critical thinking, often inviting discussion and debate.
Conclusion: The conclusion is the final part of a speech that summarizes the main points, reinforces the message, and leaves a lasting impression on the audience. It serves to tie together the entire speech and provide closure, emphasizing the key takeaways for listeners.
Deductive Reasoning: Deductive reasoning is a logical process where a conclusion is drawn from a set of premises or statements that are generally assumed to be true. It starts with a general statement or hypothesis and examines the possibilities to reach a specific, logical conclusion. This method is fundamental in constructing valid arguments and enhancing clarity when explaining concepts, ensuring that the reasoning flows logically from premises to conclusions.
Ethos: Ethos refers to the credibility or ethical appeal of a speaker, which is essential for convincing the audience of their arguments and message. This concept highlights the importance of a speaker's character, reputation, and authority in establishing trust with the audience, making it a crucial element in persuasive communication.
Evidence: Evidence refers to the information, data, or facts that support a claim or argument, helping to establish its validity and reliability. It is crucial in forming logical reasoning and strengthening arguments, allowing speakers to persuade their audience effectively. When addressing counterarguments, evidence becomes essential in rebutting opposing views and demonstrating the strength of one's position.
Inductive Reasoning: Inductive reasoning is a logical process where conclusions are drawn from specific observations or examples, leading to generalizations. This form of reasoning allows individuals to make predictions or infer broader principles based on observed patterns, making it essential for forming strong arguments and explanations.
Logos: Logos refers to the appeal to logic and reason in communication, particularly in persuasion. It involves the use of clear and rational arguments backed by evidence, statistics, and logical reasoning to influence an audience's thinking and decision-making. This method is essential for establishing credibility and convincing an audience through a structured presentation of facts and logical relationships.
Narrative: A narrative is a structured story or account that presents events, experiences, or ideas in a coherent and engaging manner. It often serves to illustrate a point, evoke emotion, or support an argument, making it a powerful tool in reasoning and persuasion. By weaving facts and personal experiences into a storyline, narratives can enhance the audience's understanding and connection to the speaker's message.
Pathos: Pathos is a rhetorical appeal that aims to evoke emotions in the audience to persuade or connect with them. By tapping into feelings such as fear, joy, sadness, or anger, speakers can create a strong emotional response that enhances their message and motivates the audience to take action or change their perspective.
Premise: A premise is a statement or proposition that serves as the foundation for an argument or conclusion. It is essential in logical reasoning, as it provides the support necessary to validate claims made within a discussion or debate. The strength and clarity of premises directly affect the overall effectiveness of an argument, making them crucial elements in persuasive communication.
Rebuttal: A rebuttal is a response that contradicts or refutes an opposing argument, presenting evidence or reasoning that challenges the validity of that argument. It plays a crucial role in logical reasoning and argumentation by helping to strengthen one's own position while addressing potential weaknesses. A well-crafted rebuttal not only counters opposition but also enhances the credibility of the speaker by demonstrating critical thinking and understanding of the topic.
Refutation: Refutation is the process of disproving or countering an argument, claim, or assertion by presenting evidence or reasoning that challenges its validity. It plays a crucial role in logical reasoning and argumentation by addressing opposing viewpoints and reinforcing the speaker's position. Effective refutation not only undermines the opposing argument but also enhances the credibility of the speaker's own claims.
Soundness: Soundness refers to the quality of an argument being both valid and having all true premises. A sound argument guarantees the truth of its conclusion based on its structure and the accuracy of its premises. In logical reasoning and argumentation, soundness is crucial as it ensures that the arguments we present are not only logically coherent but also factually accurate.
Straw man fallacy: A straw man fallacy occurs when someone misrepresents an argument to make it easier to attack or refute, rather than engaging with the actual argument being made. This tactic is often used in debates and discussions to create a false impression of an opponent's position, making it seem weaker or more absurd than it really is.
Validity: Validity refers to the extent to which an argument or statement accurately reflects the truth or correctness of the claims being made. It's crucial in logical reasoning and argumentation because it determines whether the evidence supports the conclusion, ensuring that the reasoning process is sound and reliable.