1. Education
Send to a Friend via Email

logical proof



An argument based on inductive or deductive reasoning. In classical rhetoric, logos.

See also:


From the Latin, "prove"


  • "Aristotle developed four logical methods to help people argue their way through complex issues: scientific demonstration, dialectic, rhetoric, and false or contentious reasoning. Aristotle taught that in each of these kinds of reasoning the arguer began with a statement called a premise. . . . Premises are then combined with other premises to reach conclusions."
    (S. Crowley, Ancient Rhetorics for Contemporary Students. Pearson, 2004)

  • "In a logical proof, the premises may or may not all be true, the conclusion is a consequence of the premise-set, and, therefore, the conclusion may or may not be true. What we can say in the case of a logical proof is that it is logically impossible for the conclusion to be false unless at least one of the premises is false."
    (M.R. Cohen, An Introduction to Logic. Hackett, 1993)

  • Logical proofs (SICDADS) are convincing because they are real and drawn from experience. Answer all of the proof questions that apply to your issue.
    • Signs: What signs show that this might be true?
    • Induction: What examples can I use? What conclusion can I draw from the examples? Can my readers make the "inductive leap" from the examples to an acceptance of the conclusion?
    • Cause: What is the main cause of the controversy? What are the effects?
    • Deduction: What conclusions will I draw? What general principles, warrants, and examples are they based on?
    • Analogies: What comparisons can I make? Can I show that what happened in the past might happen again or that what happened in one case might happen in another?
    • Definition: What do I need to define?
    • Statistics: What statistics can I use? How should I present them?
    (N. Wood, Perspectives on Argument. Pearson, 2004)
Also Known As: rational appeal, logos

©2014 About.com. All rights reserved.