Footer 1

Nav Bar

Become a subscriber today to get unlimited access

Member-exclusive 

You've run out of free articles. Read unlimited, ad-free stories (including this one) by becoming a Member. 

Join to continue reading

Unlock this story + our newsletter, for FREE! Already a newsletter subscriber? Just click the "Log in" link above. 

Register to continue reading.

Nautilus

<p>Brian Gallagher is an associate editor at <i>Nautilus</i>. Follow him on X (formerly known as Twitter) <a href="https://twitter.com/bsgallagher/" rel="noopener">@bsgallagher</a>.</p>


Brian Gallagher

Philosophy

The Logic Puzzle You Can Only Solve with Your Brightest Friend

common knowledge