Modus Tollens in Symbolic Logic 101- Validity, Truth, Soundness, & Fallacy of Denying the Antecedent

Описание: This is an introduction to Modus Tollens; a valid, recognized, deductive form of reasoning. We will discuss validity, truth, soundness and the fallacy of denying the antecedent.

A 'Valid' argument simply fits a recognized form of reasoning (modus tollens, modus ponens, hypothetical syllogism, constructive dilemma, disjunctive syllogism, etc.). The truth of your statements doesn't affect the fact that it is valid. Valid forms refer to the structure and "bones" of your argument, not the truth or content of it. This means that valid arguments can be false, but still technically valid.

A "Sound Argument" is valid in it's form and ALL of the premises are true. There are no counter examples to your premises. Your argument reflects reality! If your argument is sound, then your conclusion is airtight. It is 100% true.

Keep in mind that 'Validity' does not equal 'Truth'. Your argument can be valid, but the conclusion could still be false! This is why we really want "sound arguments", not just valid ones.

In Modus Tollens we are Denying the Consequent (the proposition/variable after the arrow. If you try to Deny the Antecedent in your premise (the proposition/variable before the arrow), you will have an INVALID argument. Denying the Antecedent (rather than the consequent) results in the "Fallacy of Denying the Antecedent.) Don't do this because your argument will be fallacious! In other words, there is an error in your reasoning.

If you have a specific problem, question, or example you'd like to do, please leave a comment. Thank you!

#philosophy #logic #deductivereasoning