🔍 Key insights
One Philosopher’s Modus Ponens Is Another’s Modus Tollens – I discuss with Michael Huemer why obeying the rules of logic is not enough to be rational. If P entails Q, you can reason forward from P to Q or backward from not-Q to not-P. Which move is rational depends on which statement is more plausible to begin with. That is why Huemer says skeptics who follow an abstract premise wherever it leads aren’t really following reason: when a conclusion is absurd, giving up the premise is the rational move.
Everything Starts From How Things Seem – Unless there is a specific reason for doubt, it is rational to assume things are the way they appear, whether that is the table in front of you or the wrongness of punching babies for fun. He argues that science — and any other domain of knowledge — rests on the same move. Scientists trust what they see in the field, then trust each other’s reports. Science is not an impersonal force but people.
Formal Logic Rarely Wins an Argument – Disagreements are rarely about whether a conclusion follows from the premises. They are about whether a premise is true, which comes down to evidence and how far you trust your sources. The skill that matters is extracting the premises and conclusion from a wall of text. Huemer says it is learned by watching someone take objections seriously, not by memorizing rules.
📚 Go deeper
🎥 Related videos:
Does Free Will Exist, or Even Matter? Robert Sapolsky vs. Michael Huemer – The debate where Huemer presses the self-defeat argument against hard determinism that we discuss in this conversation.
Is Most Published Research Wrong? (Veritasium) – A 12-minute explainer on p-values, publication bias and failed replications, the problems behind our discussion of how far to trust science.
Do Souls Exist? Mike Huemer (Yes) vs. Graham Oppy (No) on Parker’s Pensées – Huemer defends the immaterial soul, which comes up in our ontology discussion, against one of the leading atheist philosophers.
📖 Further reading:
Knowledge, Reality, and Value: A Mostly Common Sense Guide to Philosophy – Michael Huemer (2021). His own accessible introduction, with chapters on logic, critical thinking, skepticism and knowledge. It is the best place to see his “common sense first” method at work. Free sample: https://owl232.net/sample8.pdf
What the Tortoise Said to Achilles – Lewis Carroll (1895). A three-page dialogue we discuss, showing why a rule of inference cannot simply be added as one more premise.
🎧 Podcast to listen to:
Phenomenal Conservatism & Epistemology with Michael Huemer (Walden Pod, ep. 41) – A longer dive into the idea that seemings give us justification for belief.
💡 Think for Yourself
Think of an argument that is valid, with premises that seem reasonable, but a conclusion you are sure is false. Do you accept the conclusion, or reject a premise? What actually decides it for you?
Which of your beliefs do you hold mainly because the people around you hold them? Would you still hold it if it cost you nothing socially to drop it?
☁️ Thought Experiment
A flawless-looking argument concludes that you cannot know you have hands. Its premises are abstract claims about knowledge that sound plausible. Meanwhile, you are looking at your hands. You can keep only one: the premises or the hands. Which are you more certain of, and what does your answer say about how you reason?
Cheers,
Kevin