midterm handout

midterm handout - Philosophy 3 Midterm Handout Validity and...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Philosophy 3 – Midterm Handout Validity and Invalidity An argument is valid if and only if it’s necessary that if the premises are true, then the conclusion is true. In other words, An argument is valid if and only if it’s impossible that the premises are true and the conclusion is false. Thus, An argument is invalid if and only if it’s possible that the premises are true and the conclusion is false. Soundness and Unsoundness An argument is sound if and only if: (i) it is valid, and (ii) all of its premises are true. Thus, An argument is unsound if and only if it is either invalid or has at least one false premise (or both). Strength and Weakness An argument is strong if and only if it’s probable (but not necessary) that its conclusion is true, if its premises are true. In other words, An argument is strong if and only if it’s unlikely (but not impossible) that it’s conclusion is false, given that its premises are true. Thus, An argument is weak if and only if it’s not probable that its conclusion is true, if its premises are true. Cogency and Uncogency
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/07/2009 for the course PHIL 3 taught by Professor Way during the Winter '08 term at UCSB.

Page1 / 2

midterm handout - Philosophy 3 Midterm Handout Validity and...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online