In this video, Molly Gardner (UNC) introduces the nonidentity problem. This problem arises in cases where an individual appears to be wronged by the very action upon which his or her own existence depends. We’ll see why this problem has implications for reproductive choices, genetic engineering, and whether we should take care of the environment for the sake of future generations.
In this video, Michael Campbell introduces the Sleeping Beauty problem. This is a problem in formal epistemology about how to correctly assign probabilities to an odd scenario in which we flip a coin and, depending on the outcome, wake Sleeping Beauty up according to two different patterns. We’ll discover some very strange consequences for our beliefs as a result.
In this video, Paul Henne (Duke University) explains the post-hoc-ergo-propter-hoc fallacy. This is an informal fallacy committed when a person reasons that because one event happened after another event, the first event caused the second. He also discusses why it is sometimes hasty to conclude that your cat scratch caused your fever.
Philosophy: Conditionals Pt. 4
February 13, 2015
In this video, Justin Khoo (MIT) picks up where part 3 ( left off. He introduces the Conditional Assertion Theory of conditionals, which aims to resolve the problems presented for the other theories of conditionals. In the end, Justin presents yet another problem for this radical new theory.
In this video, Jordan MacKenzie discusses a type of informal fallacy known as the argumentum ad populum fallacy, or the appeal to the people fallacy. This fallacy occurs when one attempts to establish the truth of a conclusion by appealing to the fact that the conclusion is widely believed to be true.
In this video, Kelley builds on the understanding of necessary and sufficient conditions laid out in her previous video on the topic ( In addition to providing further illustrative examples, Kelley addresses a new complexity: that our judgments of necessity and sufficiency very often rely on implicit background assumptions. Kelley also tackles the difficult question "What's so important about distinguishing necessary from sufficient conditions anyway?".
Julia Markovits (Cornell University) gives an introduction to the moral theory of utilitarianism. Utilitarianism is the view that the right moral action is the one that maximizes happiness for all.
Philosophy: Conditionals Pt. 3
January 16, 2015
In part 3 of the series on conditionals, Justin picks up where part 2 ( leaves off, introducing an alternative theory of conditionals: the strict conditional theory. According to the strict theory, conditionals express necessary connections between their antecedent and consequent. Justin shows how this theory avoids the problems facing the material conditional theory. However, the strict theory turns out to face a similar problem of its own!
Philosophy: Conditionals Pt. 2
January 10, 2015
Justin Khoo (M.I.T.) invites us to think about conditional sentences ("if P then Q"). Perhaps surprisingly, the question of what these sentences mean has vexed philosophers for thousands of years. In part 2 of the series on conditionals, Justin discusses some of the challenges facing the material conditional theory, picking up where part 1 ( left off.
In this video, Geoff Pynn (Northern Illinois University) follows up on his introduction to critical thinking by exploring how deductive arguments give us reason to believe their conclusions. Good deductive arguments guarantee their conclusions, and so must be valid (i.e., it must be impossible for the premises to be true while the conclusion is false) and have true premises. Philosophers call arguments like these "sound". You can see whether an argument is sound by trying to think of a counterexample to it, but to see whether its premises are true, you need to do some research.
What is human nature? Is human nature good or bad? Can human nature be good even if the world contains some notably bad people? Matthew Walker (Yale-NUS College) looks at the views of the early Confucian thinker Mengzi (Mencius).
In this video, Julianne Chung (Yale University) offers a brief introduction to ad hominem fallacies, or fallacies of personal attack. She surveys six different types (abusive ad hominem, circumstantial ad hominem, tu quoque, guilt by association, genetic fallacy, and ad feminam), offering examples of each along the way. For a more detailed discussion of ad hominem fallacies, please see the video on ad hominem fallacies by Paul Henne (Duke University).
"I think, therefore I am" - almost everyone has heard of René Descartes' famous cogito argument. But what is this argument about? What does it show, and why are so many philosophers excited about it - even today, more than 350 years after Descartes first presented this argument?
In this video, Julianne Chung (Yale University) explains the philosophical concepts of truth and validity before going on to illustrate how truth and falsity, as well as validity and invalidity, can appear in various combinations in an argument. She then introduces the concept of a sound argument (i.e., a valid argument whose premises are all true) and presents one reason to think that valid arguments with false premises are also of interest. For more detailed discussions of validity and soundness, please be sure to have a look at the videos on these topics by Paul Henne (Duke University) and Aaron Ancell (Duke University), respectively.
How do we know stuff about matters of fact that we have yet to observe? For example, how do I know that the sun will rise tomorrow? A natural answer is that we have this knowledge through induction: I know the sun will rise tomorrow, because it has risen every day in the past. Now, the philosopher David Hume recognized that this inductive reasoning assumes that the future will resemble the past. Why though think that this assumption is true? How do we know that the future will resemble the past? This question is the starting point for Hume's skeptical argument against induction (and his skeptical solution), which Daniel Greco lays out in detail in this video.
According to the philosopher David Hume (1711-1776), absolutely everything we know falls into one of two categories: either it is a relation of ideas (e.g., 2 + 2 =4) or it is a matter of fact (e.g., the sky is blue). Daniel Greco walks us through this famous Humean distinction in preparation for examining Hume's even more famous skeptical argument against induction.
Critical Thinking Fundamentals: Soundness
November 14, 2014
In this video, Aaron Ancell (Duke University) 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 he encourages you to develop sound arguments on your own.
Kate explores the connection between language and meaning. This video introduces two ways in which philosophers have answered the question 'what makes a sound or some marks meaningful?'.
Critical Thinking Fundamentals: Validity
October 30, 2014
In this video, Paul Henne (Duke University) 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 validity and invalidity, and he leaves you with one example to figure out on your own.
Scott Edgar returns to Kant's argument from Geometry, this time examining two famous objections to it: the famous "neglected alternative" objection and a powerful objection from 20th century physics. After considering possible responses on Kant's behalf, Scott ends with a bang, introducing Kant's famous claim that we know things only as they appear to us, not as they are in themselves.


A Toolkit for Building a Better Mind.