Geoff Pynn tells you what critical thinking is, what an argument is, and what the difference between a deductive and an ampliative argument is. [9:49]

Paul Henne discusses the philosophical concept of validity. After reviewing the structure of an argument, he defines validity: an argument is valid if and only if its premises guarantee the conclusion. He reviews a few examples of...

Aaron Ancell discusses the philosophical concept of soundness. After reviewing validity, he defines soundness: an argument is sound when it is valid and has all true premises. He reviews a few examples of sound and unsound arguments, and...